US Army Corps

of Engineers

Construction Engineering

Research Laboratories

Technical Report REMR-OM-19

June 1997

REMR Management Systems—Navigation and Flood

Control Structures, Condition Rating Procedures

for Lock and Dam Operating Equipment

by James H. Stecker, Lowell F. Greimann, Scott Mellema, and Kevin Rens

Department of Civil and Construction Engineering

Iowa State University

and

Stuart D. Foltz

U.S. Army Construction Engineering Research Laboratories

Approved For Public Release; Distribution Is Unlimited

Prepared for Headquarters, US Army Corps of Engineers
Repair, Evaluation, Maintenance, and Technical Report REMR-OM-19

Rehabilitation Research Program June 1997

REMR Management Systems—

Navigation and Flood Control Structures

Condition Rating Procedures

for Lock and Dam Operating Equipment

by James H. Stecker, Lowell F. Greimann, Scott Mellema, and Kevin Rens

Department of Civil and Construction Engineering

Iowa State University

Ames, IA 50011

and

Stuart D. Foltz

US Army Construction Engineering Research Laboratories

PO Box 9005

Champaign, IL 61826-9005

Approved for public release; distribution is unlimited

Prepared for US Army Corps of Engineers

Washington, DC 20314-1000

Under Civil Works Research Work Unit 32672

Monitored by Maintenance Management and Preservation Division

US Army Construction Engineering Research Laboratories

PO Box 9005, Champaign, IL 61826-9005
ii

Contents

Figures ........................................................... v

Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii

Preface .......................................................... viii

Conversion Factors, Non-SI to SI Units of Measurement . . . . . . . . . . . . . . . . . . . . ix

1 Introduction ................................................... 1

1.1 Background .............................................. 1

1.2 Objective ................................................ 1

1.3 Mode of Technology Transfer ............................... 1

2 Inspection and Rating Process .................................... 2

2.1 Overview ................................................ 2

2.2 Inspection and Rating Procedure ............................. 2

2.3 Field Testing ............................................. 9

2.4 Layout of the Following Chapters . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3 Inspection Form: Historical Information . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

3.1 Lock Gates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

3.2 Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

3.3 Dam Gates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

4 Exposed Gear Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

4.1 Component Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

4.2 Inspection Form With Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

4.3 Condition Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

4.4 Field Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

5 Enclosed Gear Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

5.1 Component Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

5.2 Inspection Form With Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

5.3 Condition Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

5.4 Field Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
iii

6 Gear Rack Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

6.1 Component Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

6.2 Inspection Form With Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

6.3 Condition Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

6.4 Field Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

7 Strut Arm Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

7.1 Component Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

7.2 Inspection Form With Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

7.3 Condition Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

7.4 Field Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

8 Rocker Arm Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

8.1 Component Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

8.2 Inspection Form With Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

8.3 Condition Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

8.4 Field Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

9 Cable Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

9.1 Component Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

9.2 Inspection Form With Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

9.3 Condition Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

9.4 Field Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132

10 Chain Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138

10.1 Component Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138

10.2 Inspection Form With Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . 140

10.3 Condition Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

10.4 Field Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148

11 Hydraulic Cylinder Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150

11.1 Component Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150

11.2 Inspection Form With Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . 151

11.3 Condition Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157

11.4 Field Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161

12 Coupling Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166

12.1 Component Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166

12.2 Inspection Form With Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . 166

12.3 Condition Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169

12.4 Field Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
iv

13 Summary and Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174

Appendix A Bushing Wear Jacking Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . 175

Appendix B Gear Tooth Wear Measuring Procedures . . . . . . . . . . . . . . . . . . . . 179
v

Figures

Figure 1. Inspection and rating procedure ................................ 3

Figure 2. Condition index related to X/XMAX .............................. 7

Figure 3. Weight adjustment factor for condition index ..................... 9

Figure 4. Lock and dam schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Figure 5. Plan view of miter lock gate operating equipment . . . . . . . . . . . . . . . . . 25

Figure 6. Side view of tainter valve operating equipment . . . . . . . . . . . . . . . . . . . 31

Figure 7. Plan view of dam gate operating equipment . . . . . . . . . . . . . . . . . . . . . . 41

Figure 8. Plan view of sector lock gate operating equipment (gear and rack) . . . . 41

Figure 9. Reduction gear schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Figure 10. Gear anchorage movement/deterioration measurement . . . . . . . . . . . . 50

Figure 11. Tooth contact location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Figure 12. Anchorage movement/deterioration:. exposed gear assembly . . . . . . . 58

Figure 13. Bearing/bushing wear: exposed gear assembly . . . . . . . . . . . . . . . . . . 58

Figure 14. Reduced tooth contact: exposed gear assembly . . . . . . . . . . . . . . . . . . 59

Figure 15. Exposed gear assembly CI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Figure 16. Noise, jumping, and vibration: enclosed gear assembly . . . . . . . . . . . 71

Figure 17. Anchorage movement/deterioration: enclosed gear assembly . . . . . . . 71

Figure 18. Damaged teeth: enclosed gear assembly . . . . . . . . . . . . . . . . . . . . . . . 72

Figure 19. Temperature rise of oil: enclosed gear assembly . . . . . . . . . . . . . . . . . 72

Figure 20. Oil leakage: enclosed gear assembly . . . . . . . . . . . . . . . . . . . . . . . . . . 73

Figure 21. Oil contamination: enclosed gear assembly . . . . . . . . . . . . . . . . . . . . . 73

Figure 22. Enclosed gear assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Figure 23. Gear/rack displacement measurement . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Figure 24. Reduced tooth contact: gear rack assembly . . . . . . . . . . . . . . . . . . . . . 89

Figure 25. Gear/rack displacement: gear rack assembly . . . . . . . . . . . . . . . . . . . . 89

Figure 26. Gear rack assembly CI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

Figure 27. End connection movement distress . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

Figure 28. End connection movement: strut arm assembly . . . . . . . . . . . . . . . . . 100

Figure 29. Corrosion: strut arm assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

Figure 30. Strut arm assembly CI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

Figure 31. Rocker arm distress measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

Figure 32. Pivot point anchorage movement/deterioration: 

rocker arm assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

Figure 33. Pivot point pin movement: rocker arm assembly . . . . . . . . . . . . . . . . 108

Figure 34. Rocker arm assembly CI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

Figure 35. Plan view of sector lock gate operating equipment . . . . . . . . . . . . . . 111

Figure 36. Side view of tainter dam gate operating equipment . . . . . . . . . . . . . . 112
vi

Figure 37. Vertical lift gate operating equipment . . . . . . . . . . . . . . . . . . . . . . . . 113

Figure 38. Cable schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

Figure 39. Plan view of tainter gate operating equipment . . . . . . . . . . . . . . . . . . 114

Figure 40. Location identification for cable and chain distresses . . . . . . . . . . . . 124

Figure 41. Cable bird cage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

Figure 42. Cable protruded core . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

Figure 43. Cable drum wear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

Figure 44. Outer wire wear: cable assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . 132

Figure 45. Wire breakage: cable assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

Figure 46. Cable assembly CI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

Figure 47. Side view of roller dam gate operating equipment . . . . . . . . . . . . . . 138

Figure 48. Chain link schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

Figure 49. Chain linkage wear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

Figure 50. Hydraulic cylinder assembly distress measurements . . . . . . . . . . . . . 156

Figure 51. Anchorage movement/deterioration: hydraulic cylinder assembly . 162

Figure 52. Corrosion/pitting of rod: hydraulic cylinder assembly . . . . . . . . . . . 162

Figure 53. Oil leakage: hydraulic cylinder assembly . . . . . . . . . . . . . . . . . . . . . 163

Figure 54. Drift: hydraulic cylinder assembly . . . . . . . . . . . . . . . . . . . . . . . . . . 163

Figure 55. Hydraulic cylinder assembly CI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

Figure 56. Coupling relative movement measurement . . . . . . . . . . . . . . . . . . . . 169

Figure 57. Input shaft and hub movement: coupling assembly . . . . . . . . . . . . . 171

Figure A1. Bushing wear measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176

Figure A2. Vertical displacements when jacked on Side 1 . . . . . . . . . . . . . . . . . 176

Figure A3. Vertical displacements when jacked on Side 2 . . . . . . . . . . . . . . . . . 177

Figure A4. Displaced shape of gear (bowed and unbowed) . . . . . . . . . . . . . . . . 178

Figure B1. Gear tooth dimensions and wear measurement . . . . . . . . . . . . . . . . . 179

Figure B2. Gear tooth wear measurement: Procedure 1 . . . . . . . . . . . . . . . . . . . 182
vii

Tables

Table 1. List of operating equipment assemblies. .......................... 5

Table 2. Condition index scales and zones. ............................... 6

Table 3. Exposed gear assembly distresses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Table 4. Enclosed gear assembly distresses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Table 5. Gear rack assembly distresses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Table 6. Strut arm assembly distresses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Table 7. Rocker arm assembly distresses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Table 8. Cable assembly distresses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Table 9. Chain assembly distresses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Table 10. Hydraulic cylinder assembly distresses. . . . . . . . . . . . . . . . . . . . . . . . . . 14

Table 11. Coupling assembly distresses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Table 12. Weighting factors for the exposed gear assembly. . . . . . . . . . . . . . . . . . 15

Table 13. Weighting factors for the enclosed gear assembly. . . . . . . . . . . . . . . . . 15

Table 14. Weighting factors for the gear rack assembly (sector gate racks). . . . . . 15

Table 15. Weighting factors for the gear rack Assembly (other applications). . . . 16

Table 16. Weighting factors for the strut arm assembly. . . . . . . . . . . . . . . . . . . . . 16

Table 17. Weighting factors for the rocker arm assembly. . . . . . . . . . . . . . . . . . . 16

Table 18. Weighting factors for the cable assembly. . . . . . . . . . . . . . . . . . . . . . . . 17

Table 19. Weighting factors for the chain assembly. . . . . . . . . . . . . . . . . . . . . . . . 17

Table 20. Weighting factors for the hydraulic cylinder assembly. . . . . . . . . . . . . . 18

Table 21. Weighting factors for the coupling assembly. . . . . . . . . . . . . . . . . . . . . 18

Table B1. Gear tooth relationships. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
viii

Preface

The study reported herein was authorized by Headquarters, U.S. Army Corps of

Engineers (HQUSACE), as part of the Operations Management problem area of the

Repair, Evaluation, Maintenance, and Rehabilitation (REMR) Research Program. 

The work was performed under Civil Works Research Work Unit 32672, “Development of Uniform Evaluation for Procedures/Condition Index for Deteriorated

Structures and Equipment,” for which Stuart Foltz is the Principal Investigator. Mr.

James E. Crews (CECW-O) is the REMR Technical Monitor for this work.

Mr. David B. Mathis (CERD-C) is the REMR Coordinator at the Directorate of

Research and Development, HQUSACE; Mr. James Crews and Dr. Tony C. Liu

(CEEC-ED) serve as the REMR Overview Committee; Mr. William F. McCleese,

U.S. Army Engineer Waterways Experiment Station, is the REMR Program Manager; Mr. David T. McKay is the Problem Area Leader for the Operations Management problem area.

This study was performed by the Department of Civil and Construction Engineering, Iowa State University, under contract to the U.S. Army Construction

Engineering Research Laboratories (USACERL). Principal Investigators for Iowa

State University were Lowell Greimann, James Stecker, and Timothy Kraal. The

study was conducted under the general supervision of Dr. Simon S. Kim, Chief of

the Maintenance Management and Preservation Division (FL-P), Infrastructure

Laboratory (FL), USACERL. The USACERL technical editor was Linda L.

Wheatley, Technical Resources Center.

Special thanks are extended to the following Corps experts who participated in

the development of this study: Mr. Fred Joers and Mr. Jim Bartek (Rock Island

District), Mr. Allen Matherne (New Orleans District), Mr. Ross Woodbury (Louisville District), and Mr. Joe Britton and Mr. Steven Schneider (Jacksonville District).

COL James T. Scott was Commander and Acting Director of USACERL, and

Dr. Michael J. O'Connor was Technical Director.
ix

Conversion Factors, Non-SI to

SI Units of Measurement

Non-SI units of measurement used in this report can be converted to SI (metric)

units as follows:

Multiply By To Obtain 

feet 0.3048 meters

inches 0.0254 meters

square ft 0.0929 square meters
1

1 Introduction

1.1 Background

Demand for new construction of civil works projects is frequently overridden

by the need to maintain existing projects. Many existing civil works structures are

nearing the end of their design life, yet service to the public must be maintained. 

The U.S. Army Corps of Engineers (USACE) Repair, Evaluation, Maintenance, and

Rehabilitation (REMR) program was designed to focus attention on maintenance

and to record and build baseline data to monitor deterioration rates of these structures.

This REMR project addressed equipment used to operate lock, valve, and dam

structures, which include assemblies such as: exposed gear assemblies, enclosed

gear assemblies, gear rack assemblies, strut arm assemblies, rocker arm assemblies,

cable assemblies, chain assemblies, hydraulic cylinder assemblies, and coupling

assemblies. Not included in this evaluation of operating equipment are hydraulic

motors, pumps, hoses, or valves, limit switches, brakes, electric wiring, and electric

motors.

1.2 Objective

A research team, applying the REMR project objectives to lock and dam

operating equipment, has developed an inspection program to detect problems in

operating equipment at an early stage. The objective of this project is to develop an

inspection and rating procedure to describe the overall condition of operating

equipment assemblies accurately. Such a rating will also flag a potential problem

for the engineer.

1.3 Mode of Technology Transfer

It is recommended that the inspection procedures developed in this study for

operating equipment be incorporated into Engineer Regulation (ER) 1110-2-100,

Periodic Inspection and Continuing Evaluation of Completed Civil Works Structures.
2

2 Inspection and Rating

Process

2.1 Overview

The concepts and ideas presented here for the maintenance management of

operating equipment rely heavily on work in similar projects for steel sheet pile

structures (Greimann and Stecker 1990), miter lock gate structures (Greimann,

Stecker, and Rens 1990), sector gate structures (Greimann, Stecker, and Rens 1993),

tainter and butterfly valves (Greimann, Stecker, and Veenstra 1994), and tainter dam

and lock gates (Greimann, Stecker, and Nop 1995). During that earlier work, basic

ideas such as structural considerations, condition indexes, safety and serviceability,

quantification of distresses by field measurements, and limiting values of distresses

began to evolve. As these concepts were applied to lock and dam operating

equipment, several enhancements and some new ideas became apparent.

During the course of this project, the research team has met with Corps

personnel and conducted site visits and field investigations at many lock and dam

facilities. These meetings led to the identification of several basic considerations for

operating equipment. Corps experts expressed their opinions as to the critical

components of lock and dam operating equipment, suggested means of quantifying

the condition of these components, and related them to the overall condition of the

operating equipment assemblies. The project team then formulated the experts'

comments into an inspection procedure and a tentative set of rating rules. Field tests

of the inspection form and rating rules were conducted at 16 lock and dam facilities. 

At each test site, experts suggested improvements to the rules and inspection

process. Insofar as possible, the suggestions have been incorporated into this work

except for cases of conflicting expert opinion. Software will be written to store the

inspection data and calculate the condition rating.

2.2 Inspection and Rating Procedure

The inspection and rating procedure is illustrated schematically in Figure 1. 

The entire process is based on a field inspection of the operating equipment.
3

F ie ld I n s p e c tio n

D a ta E n try

E x p e rt R u le s

C o n d itio n In d e x

R e p o rt G e n e ra tio n S tru c tu ra l N o te s

Figure 1. Inspection and rating procedure

Field Inspection Procedure

Simplicity and adaptability form the basis of the inspection procedure. 

Conforming to these guidelines, the inspection program had to be applicable to a

wide variety of operating equipment yet relatively straightforward for Corps

personnel to implement in the field.

For rating systems previously developed by the research team, the field

inspection was based on easily obtainable data. All data were measured with a tape

measure, a level, a ruler, dial gages, or by subjective observation (poor, average,

good, excellent). The procedure was kept as simple as possible, while still obtaining

quantitative and applicable information to assess the structure. The lock and dam

may remain in operation during the procedure. In general, the level of inspection for

operating equipment is at a somewhat lower level of inspection than for previously
4

inspected structures (e.g., dam gates). Hence, some rules involve more subjective

questions to quantify the condition.

In addition to simplicity, the other goal was to develop a general inspection

procedure that was adaptable to many types of operating equipment. The equipment

covered in this report include lock, valve, and dam operating equipment. Within

each of these structures are numerous designs and combinations of assemblies. For

example, dam gates can be operated by various combinations of exposed gears,

enclosed gears, gear racks, struts, cables, chains, hydraulic cylinders, and couplings. 

To accommodate these variations, separate inspection forms were developed for

each assembly comprised in the operating equipment.

Inspection Form

The inspection forms for lock gate, valve, and dam gate operating equipment

were designed to be flexible in documenting a variety of field conditions. The first

two pages of the form address location of the equipment, historical information,

inspection and maintenance history, and the current operating characteristics. These

pages should be completed before the field inspection. Pages beyond the first two

provide space for entering field measurements such as anchorage movements,

cracks, and corrosion and should be completed in the field. These measurements are

used directly to rate the condition of the operating equipment. The following

paragraphs briefly outline the inspection form.

General Information. General information related to the structure is recorded

on pages 1 and 2 of the inspection form, which are shown and described in detail in

Chapter 3. Separate page 1 and 2 sets were developed for the operating equipment

for: (1) lock structures, (2) valve structures, and (3) dam structures. Recorded

information includes project reference data to identify and locate the specific

structure. Further questions categorize the structure into a particular type and

function. In particular, the path of power transfer through the assemblies, from the

power source to the structure, is itemized on page 1. The assemblies identified on

page 1 constitute the basis for selecting the inspection forms that will be used to

inspect the condition of the operating equipment assemblies within the structure. 

Historical descriptions of maintenance, modifications, and inspections are recorded

on page 2 for reference only.

Field measurements. The remaining pages of the inspection form are used to

describe the condition of each assembly that makes up the operating equipment. The

inspection forms that describe the condition of each assembly consist of one to three

pages, which are identified as Parts 1, 2, and 3. The complete inspection form set
5

Assembly Inspection and Rating Procedure

Exposed Gear Chapter 4

Enclosed Gear Chapter 5

Gear Rack Chapter 6

Strut Arm Chapter 7

Rocker Arm Chapter 8

Cable Chapter 9

Chain Chapter 10

Hydraulic Cylinder Chapter 11

Coupling Chapter 12

Table 1. List of operating equipment assemblies.

for a structure will consist of one page 1, one page 2, and a number of pages to

describe the condition of the assemblies, depending on the type and number of 8

assemblies in the operating equipment. Separate sets of inspection forms exist for

each of the nine assemblies listed in Table 1. Several simple measurements and

observations concerning problems or distresses in each assembly are recorded. The

inspection forms corresponding to the separate assemblies are in Chapters 4 through

12.

Condition Index

The field observations are used in the expert rules to determine the condition

index (CI) for each operating equipment assembly. A condition index is the

numerical measure used to rate the current state of the operating equipment. The

purpose of the CI is twofold. First, the CI values serve as a planning tool meant to

focus management attention on operating equipment most likely to warrant immediate repair or further evaluation. Second, the CI values can be used to monitor

changes in the general condition over time and can serve as an approximate comparison of the condition of operating equipment at different locations.

A common definition of CI was developed during previous REMR work done

by the research team (Table 2). The REMR CI is a numerical scale, ranging from a

low of 0 to a high of 100. The numbers indicate the relative need to perform REMR

work because of deteriorating characteristics of the operating equipment. For

management purposes, the CI scale is also calibrated to group operating equipment

into three basic categories or zones, as listed in Table 2. If a structure is designed

and constructed properly, it has an initial CI of 100. As time passes and the

structure is exposed to varying environmental and operational situations, its

condition will deteriorate. The CI will degrade as various distresses are incurred.
6

Zone Condition

Index

Condition Description Recommended

Action

1

85 to 100 Excellent: No noticeable

defects. Some aging or wear

may be visible.

Immediate action is

not required.

70 to 84 Good: Only minor deterioration

or defects are evident.

2

55 to 69 Fair: Some deterioration or

defects are evident, but function

is not significantly affected.

Economic analysis of

repair alternatives is

recommended to

determine appropriate

action. 40 to 54 Marginal: Moderate

deterioration. Function is still

adequate.

3

25 to 39 Poor: Serious deterioration in at

least some portions of the

structure. Function is

inadequate.

Detailed evaluation is

required to determine

the need for repair,

rehabilitation, or

reconstruction.

Safety evaluation

recommended.

10 to 24 Very Poor: Extensive

deterioration. Barely functional.

0 to 9 Failed: No longer functions. 

General failure or complete

failure of a major structural

component.

Table 2. Condition index scales and zones.

Because the CI involves engineering judgment and depends on the experience

of the person making the evaluation, some aspects of the CI were difficult to

capture. Experts in the area of operating equipment were interviewed, and discussion continued until a consensus began to develop. A set of “expert opinion” rules

are embedded in the evaluation that constitutes the CI. The rules have been

designed to interpret straightforward, visual observation data in much the same

manner that a seasoned engineer would interpret field observations.

Two general structural criteria for evaluating the CI were considered: safety

and serviceability. Safety relates to the performance of a structure beyond normal

service conditions, for example, under excessive load. It relates to the probability of

failure. Serviceability relates to the performance of operating equipment under

normal service conditions (e.g., hydraulic cylinder drift). The CI for each distress

includes aspects of both safety and serviceability. Compared to other structural

components at a lock and dam facility, few safety aspects are associated with

operating equipment.

A series of critical measurements and observations are made on each operating

equipment assembly to quantify the CI. Experts were asked to interpret these

measurements in light of the serviceability and safety of the operating equipment

and to assign the limiting values to the measurements.
*

 Tables 3 through 21 are placed at the end of the chapter.

7

 (2.1)

Figure 2. Condition index related to X/XMAX.

Distress CI. Each assembly in this project has between five and fifteen distresses that affect the assembly CI. Each distress can detract from the safety and the

serviceability of that assembly. Tables 3 through 11*

 contain a brief description of

the distresses for each of the nine assemblies listed in Table 1. Many distresses are

quantified by a measurement X. For example, hydraulic cylinder drift is a distress

quantified by the motion of the cylinder rod when the oil valves are closed. In this

case, the CI is calculated by:

where XMAX is some limiting value of X. Figure 2 illustrates the equation and the

previously mentioned zones (Table 2). Experts selected XMAX to be the point at

which the operating equipment requires immediate repair or at least a more detailed

inspection and CI evaluation. In other words, it corresponds to a CI of 40 and is a

potentially hazardous situation.

In Chapters 4 through 12, the definition and measurement of X and XMAX

values are described for each assembly. Illustrated examples and potential causes of

each distress that must be addressed in the maintenance and repair of the operating

equipment are also included. Diagnosing causes for each distress is a complex issue. 

Many times a distress may have several possible causes, and a combination of

distresses often must be present before a certain cause can be identified.
8

 (2.2)

 b (2.3)

b  (2.4)

Assembly CI. The calculation of the assembly CI is also a complicated task. 

Although all of the individual CIi

s (where I refers to an individual distress) contribute to the assembly CI, some are more significant in evaluating the overall condition of the assembly. To account for this varying significance, weighting factors, wi

,

were obtained for each CIi

. Weighting factors were obtained by averaging the

subjective weighting factors given by five operating equipment experts from the

Army Corps of Engineers: Fred Joers (Rock Island District), Jim Bartek (Rock

Island District), Ross Woodbury (Louisville District), Allen Matherne (New Orleans

District), and Joe Britton (Jacksonville District).

Before the weighting factors were established by the experts, each expert was

sent a letter and rating form that asked the experts to identify the importance of each

distress and to determine whether it should be considered (1) critical to the structural

stability of the assembly or (2) noncritical. The CI of a critical distress can control

the assembly CI, which is the minimum of the CI for the critical distresses and

weighted average of all the noncritical distresses.

where CIj

s are the CIs of the critical distresses (j refers to critical distresses) and CI w

is the weighted average of the noncritical distresses (discussed in the following

paragraph). Eight of the nine assemblies have at least one distress that is considered

critical. None of the distresses are critical in the hydraulic cylinder assembly.

After analyzing the responses to the first letter, The experts were sent a second

letter and rating form— this time asking for the relative weights, wi

, of each distress

that they considered noncritical. The weighting factors were normalized with the

following equation:

such that

Tables 12 through 21 list the experts’ average weighting factors and the normalized

weighting factors for each of the nine assemblies with the exception of the gear rack
9

 (2.5)

    (2.6)

Figure 3. Weight adjustment factor for condition index.

assembly for which there are two tables (one for the sector gate application and one

for the other gear rack applications). The normalized weighting factors are used to

calculate the weighted average CIw for the noncritical distresses

where n is the number of noncritical distresses for that assembly. 

As the CIi

 of an individual distress approaches Zone 3, it becomes more

significant in the calculation of the weighted CIw. In previous work, an adjustment

factor (AF) was applied to the weighting factors of distresses for which the individual CIi

 was less than 70 (or in Zones 2 or 3). The AF has a maximum value of

eight when the individual CIi

 is in Zone 3 and is obtained by the following linear

equation when the individual CIi

 is in Zone 2:

Figure 3 shows the value of the adjustment factor versus the CIi

.

2.3 Field Testing

The performance of the rating rules was evaluated by comparing the calcu-
10

lated CI values based on the rules with the CI values subjectively determined by

Corps operating equipment experts. During several site visits, Corps experts were

interviewed to establish an initial set of CI rules. In January 1995, several field tests

of operating equipment were performed in the Jacksonville District. The lock and

dam sites for the tests were: (1) W.P. Franklin Lock and Dam, (2) Ortona Lock and

Dam, (3) Moore Haven Lock and Dam, and (4) St. Lucie Lock and Dam. The Corps

personnel who participated were: Fred Joers (Rock Island District), Jim Bartek

(Rock Island District), Ross Woodbury (Louisville District), Allen Matherne (New

Orleans District), Joe Britton (Jacksonville District), and Steve Schneider

(Jacksonville District). Each expert was asked to rate subjectively the individual

distresses for various operating equipment assemblies by assigning a CI to each

distress. The experts were also asked to assess a combined assembly CI. After the

field test, the inspection procedure and inspection forms were changed significantly

in response to recommendations by the experts.

Field tests were conducted in March 1995 in the Louisville District at: 

(1) Cannelton Lock and Dam, (2) Green River 1 Lock and Dam, (3) Green River 2

Lock and Dam, and (4) Newburgh Lock and Dam. The participating Corps

operating equipment experts were Joers, Bartek, Matherne, Woodbury, and Britton. 

The same calibration procedure was used to further refine and improve the

inspection process, form, and rules.

Bar charts in Chapters 4 through 12 compare the experts’ subjective CIs to the

calculated individual and assembly CIs. In each chart, the individual bars represent:

! the average expert CI

! the highest expert CI

! the lowest expert CI

! the CI calculated by rating rules.

Some distresses were not observed in the tested assemblies during field testing. In

these cases, the calculated CIi

s were 100 and the experts’ average CIis were at least

90. Therefore, these cases are not presented in the bar charts. An expert adjusted

average CI (the average of the experts’ CIs excluding the highest and the lowest)

was calculated and compared with the experts’ average CI. The two averaging

methods yielded approximately the same results; therefore, only the average of the

experts’ CI is shown.

Operating equipment was observed in June 1995 at the following Illinois lock

and dam sites: (1) T.J. O'Brien Lock and Dam, (2) Chicago Lock, (3) Lockport

Lock and Dam, (4) Brandon Road Lock and Dam, (5) Dresden Island Lock and

Dam, (6) Marseilles Lock and Dam, (7) Starved Rock Lock and Dam, and (8)
11

Mississippi River Lock and Dam #16. Joers and Bartek participated in these visits.

The inspection procedures for several of the assembly distresses were performed at

the above sites in an effort to (1) fine tune the procedures, (2) make format changes

to the inspection form, and (3) adjust the CI calculation rules. The visits were

beneficial in reformatting the inspection form and finalizing the inspection

procedure and rules for some of the distresses.

2.4 Layout of the Following Chapters

One of the nine operating equipment assemblies listed in Table 1 is described

in each of the Chapters 4 through 12. In addition to component identification, these

chapters include the inspection forms pertaining to the nine assemblies. The rules

for evaluating the individual CIi

s and combined assembly CIs with example

illustrations showing the calculations of these CIi

s are also included. The final

section of each chapter compares the CIs calculated from the rules assembled by the

research team with the subjective CIs given by the experts for assembly and

combined distresses.
12

Table 3. Exposed gear assembly distresses.

Distress Brief Description

Noise, jump, vibration Abnormal noise, jumping, or vibration during operation

Anchorage movement, deterioration Movement of embedded anchorage system and damaged components

Bearing/bushing wear Excessive play in the exposed reduction gear bearing or bushing

Roller support wear/damage Freezing or wear of the roller bearings or bushings

Cracks Breaks in the steel components

Tooth wear Wearing of the gear teeth

Reduced tooth contact Improper engagement of the teeth

Damaged teeth Chipped, deformed, pitted, gouged, or corroded teeth 

Table 4. Enclosed gear assembly distresses.

Distress Brief Description

Noise, jump, vibration Abnormal noise, jumping, or vibration during operation 

Anchorage movement, deterioration Movement of embedded anchorage system and damaged components

Cracks Breaks in the steel components

Damaged teeth Chipped, deformed, pitted, gouged, or corroded teeth 

Temperature rise of gear box Temperature change in the gear box oil 

Oil leakage Leakage of oil 

Oil contamination Contamination of oil 

Table 5. Gear rack assembly distresses.

Distress Brief Description

Noise, jump, vibration Abnormal noise, jumping, or vibration during operation

Cracks Breaks in the steel components

Rack attachment deterioration Deterioration of bolts which anchor the rack to the gate

Reaction roller wear/damage Wear and freezing of reaction roller bearings and bushings

Reaction roller anchorage 

movement /deterioration

Movement of embedded anchorage system and 

damaged components 

Gear/rack displacement Relative displacement between the gear and rack perpendicular to the

rack

Rack wear Edge and bottom wear of the rack

Tooth wear Wearing of the gear teeth

Reduced tooth contact Improper engagement of the teeth

Damaged teeth Chipped, deformed, pitted, gouged, or corroded teeth
13

Table 6. Strut arm assembly distresses.

Distresses Brief Description

Noise, jump, vibration Abnormal noise, jumping, or vibration during operation

Strut connection movement Displacement between pin and bushing

Compression spring movement Abnormal functioning of the compression spring

Corrosion Loss of steel due to interaction with the environment

Cracks Breaks in the steel components

Table 7. Rocker arm assembly distresses.

Distresses Brief Description

Noise, jump, vibration Abnormal noise, jumping, or vibration during operation

Rocker and connecting rod

connection movement

Movement between the rocker arm and the connecting rod

Pivot point anchorage 

movement/deterioration

Movement of embedded anchorage system and damaged

components

Pivot point pin movement Movement between the rocker arm the pivot point anchorage system

Corrosion Loss of steel due to interaction with the environment

Cracks Breaks in the steel components

Table 8. Cable assembly distresses.

Distresses Brief Description

Noise, jump, and vibration Abnormal noise, jumping, or vibration during operation

Outer wire wear Reduction in the diameter of the cable wires

Reduction in rope diameter A reduced rope diameter 

Corrosion Loss of steel due to interaction with the environment

Bird cages, kinks, and protruding

core

Deformation of the rope by either bird cages, kinks in the rope, or

a core which is protruding from the rope

Unlayed strands Cable strands which are unlayed

Wire breakage The number of broken wires in any one cable lay 

Unequal tension Improper cable tension

Drum wear Wear on cable guides and drum groove 

Drum anchorage

movement/deterioration

Movement of embedded anchorage system and damaged

components 

Sheave wear Wear on the sheave groove

Sheave bearing/bushing wear Excessive play in the sheave bearing or bushing

Sheave anchorage

movement/deterioration

Movement of embedded anchorage system and damaged

components 

Idler/roller wear Improper operation of idlers and rollers

Gate or valve connection movement Relative movement at the connection between the cable and the

lifting bracket 
14

Table 9. Chain assembly distresses.

Distresses Brief Description

Noise, jump, vibration Abnormal noise, jumping, or vibration during operation

Linkage wear/elongation Wear and elongation of the chain links, pins, and bearings

Cracks Breaks in the steel components

Frozen links Links will not rotate or displace relative to each other

Corrosion Loss of steel due to interaction with the environment

Sprocket anchorage

movement/deterioration

Movement of embedded anchorage system and damaged components

Sprocket wear Wear of the sprocket

Gate connection movement Relative movement between the chain and the lifting bracket 

Table 10. Hydraulic cylinder assembly distresses.

Distresses Brief Description

Noise, jump, vibration Abnormal noise, jumping, or vibration during operation

Anchorage movement, deterioration Movement of embedded anchorage system and damaged components

Rod end connection movement Relative movement between the hydraulic rod and the strut

Corrosion/pitting of rod Corrosion and possibly pitting of hydraulic rod due to interaction with the

environment

Damage of rod Scoring, nicking, or other damage on the rod

Oil leakage Leakage of oil from the rod end of the hydraulic cylinder

Drift Movement of hydraulic rod with respect to the cylinder with load 

Damaged guide Corrosion and/or attachment movement of the guides

Table 11. Coupling assembly distresses.

Distress Brief Description

Noise, jump, vibration Abnormal noise, jumping, or vibration during operation 

Cracks Breaks in the steel components

Corrosion Loss of steel due to interaction with the environment

Input shaft and hub movement Relative movement between the input shaft and the hub 

Output shaft and hub movement Relative movement between the output shaft and the hub 
15

Table 12. Weighting factors for the exposed gear assembly.

Distress Wi

Noise, jump, and vibration 27.5

Anchorage movement/deterioration 26.8

Bearing/bushing wear 12.3

Roller supports wear/damage* 7.0

Cracks critical

Tooth wear 2.6

Reduced tooth contact 9.0

Damaged teeth 14.8

* If not applicable, wi

 for this distress is zero.

Table 13. Weighting factors for the enclosed gear assembly.

Distress Wi

Noise, jump, and vibration 24.1

Anchorage movement/deterioration 21.5

Cracks* critical

Damaged teeth* 23.3

Temperature rise of gear box 17.2

Oil leakage 2.3

Oil contamination 11.6

* If not observable, wi

 for this distress is zero.

Table 14. Weighting factors for the gear rack assembly (sector gate racks).

Distress Wi

Noise, jump, and vibration 34.3

Cracks critical

Rack attachment deterioration 25.1

Tooth wear 6.4

Reduced tooth contact 14.3

Damaged teeth 19.9
16

Table 15. Weighting factors for the gear rack Assembly (other applications).

Distress Wi

Noise, jump, and vibration 29.0

Cracks critical

Reaction roller wear/damage 10.2

Reaction rollers anchorage movement/deterioration 15.4

Gear/rack displacement 9.0

Rack wear 3.2

Tooth wear 4.9

Reduced tooth contact 11.4

Damaged teeth 16.9

Table 16. Weighting factors for the strut arm assembly.

Distress Wi

Noise, jump, and vibration 44.5

Strut connection movement 20.6

Compression spring movement 27.7

Corrosion 7.2

Cracks critical

Table 17. Weighting factors for the rocker arm assembly.

Distress Wi

Noise, jump, and vibration 27.7

Rocker and connecting rod connection movement 19.3

Pivot point anchorage movement/deterioration 38.9

Pivot point pin movement 4.9

Corrosion 9.2

Cracks critical
17

Table 18. Weighting factors for the cable assembly.

Distress Wi

Noise, jump, and vibration 9.1

Outer wire wear 7.5

Reduction in rope diameter 14.1

Corrosion 8.8

Bird cages, kinks, and protruding core critical

Unlayed strands 10.5

Wire breakage critical

Unequal tension 7.0

Drum wear 1.3

Drum anchorage movement/deterioration 10.6

Sheave wear* 2.7

Sheave bearing/bushing wear* 4.1

Sheave anchorage movement/deterioration* 10.6

Idlers/rollers wear* 3.4

Gate or valve connection movement** 10.5

* If not applicable, wi

 for this distress is zero.

** If not observable, wi

 for this distress is zero.

Table 19. Weighting factors for the chain assembly.

Distress Wi

Noise, jump, and vibration 16.3

Linkage wear/elongation 12.3

Cracks critical

Frozen links 23.6

Corrosion/pitting 9.7

Sprocket anchorage movement/deterioration 21.8

Sprocket wear 2.9

Gate connection movement** 13.4

** If not observable, wi

 for this distress is zero.
18

Table 20. Weighting factors for the hydraulic cylinder assembly.

Distress Wi

Noise, jump, and vibration 18.1

Anchorage movement/deterioration 21.0

Rod end connection movement 13.1

Corrosion/pitting of rod 12.3

Damage of rod 14.8

Oil leakage 7.4

Drift 11.2

Damaged guide* 2.1

* If not applicable, wi

 for this distress is zero.

Table 21. Weighting factors for the coupling assembly.

Distress Wi

Noise, jump, and vibration 89.3

Cracks critical

Corrosion 10.7

Input shaft and hub movement critical

Output shaft and hub movement critical
19

LOCK GATE

VALVE OPERATING 

 EQUIPMENT

STILLING BASIN

 DAM 

OPERATING 

EQUIPMENT

DAM GATES

FLOW

GATE OPERATING

 EQUIPMENT

Figure 4. Lock and dam schematic.

3 Inspection Form: Historical

Information

This chapter contains pages 1 and 2 of the inspection forms for: (1) lock gate,

(2) valve, and (3) dam gate operating equipment. The side-by-side arrangement of

the opposing pages displays specific explanations (right side) adjacent to the entry

on the inspection form (left side). The chapter begins with a brief description of

lock gates, valves, and dam gates. An overall view of a lock and dam facility is

shown in Figure 4, in which various operating equipment areas are highlighted.
20

3.1 Lock Gates

Lock gates can be miter, sector, tainter, or vertical lift lock gates. Miter gates

rotate on hinges that are attached to the concrete monolith wall and resist forces

similar to a three-hinged arch. Sector gate structures have skin plates that are

sectors of a circle. Sector gates can resist water pressure on either side of the skin

plate; whereas miter gates can have net water pressure only on the upstream side. 

Tainter lock gates sometimes serve as upper gates in a lock chamber and are usually

submersible. Vertical lift gates are comprised of skin plates that are framed with

horizontal and vertical girders.

3.2 Valves

Valves are used inside the culverts of the filling and emptying systems of lock

structures. At least two valves are necessary in each longitudinal culvert. A filling

valve is located between the upper pool intake and the chamber intake ports. An

emptying valve is located between the chamber outlet ports and the lower pool

discharge. Some of the most common valve types are tainter, vertical lift, and

butterfly.

3.3 Dam Gates

Dam gates are used at the top of a dam spillway to control the upper pool

elevation by holding back or passing water. The types of dam gates currently used

are tainter, vertical lift, and roller.
21

Intentionally Blank
22

U. S. ARMY CORPS OF ENGINEERS PAGE 1

LOCK GATE LEAF OPERATING EQUIPMENT INSPECTION

NAME OF CIVIL WORKS PROJECT:

 

 

LOCATION OF CIVIL WORKS PROJECT: (1. Body of water, 2. Nearest town)

1. 

2. 

INSPECTION DATE: INSPECTED BY: 

GATE IDENTIFICATION: (circle the correct gate, leaf, and type of gate)

Upper Gate 1. Left Leaf 2. Right Leaf

Lower Gate 1. Left Leaf 2. Right Leaf

GATE TYPE

1. Miter

2. Sector

3. Tainter

4. Vertical Lift

ASSEMBLY LIST AND ORDER OF POWER TRANSFER

 COMMON LEFT RIGHT

Exposed gear 

Enclosed gear 

Gear rack 

Strut arm 

Rocker arm 

Cable 

Chain 

Hydraulic cylinder 

Coupling 
23

Page 1. Comments: Recordkeeping Data

Completed before the site inspection and verified or changed during the site inspection.

Enter the NAME of the Corps of Engineer Project Title.

Indicate the BODY OF WATER and NEAREST TOWN.

Indicate GATE IDENTIFICATION. Circle the gate that will be inspected and the TYPE

of gate. The orientation of the gate, left or right, is determined by looking downstream.

Select ASSEMBLIES that exist in the operating equipment and number them in order of

POWER TRANSFER from source of the power to the structure. If the equipment splits

into a LEFT and RIGHT set of equipment, place the power transfer number in the

columns labeled left and right, respectively. Place an L behind the number if it is on the

left side and an R behind the number if it is on the right side. If the assembly is common

to (shared by) both sides or if there is no power split, place the numbers in the

COMMON column. Left and right are determined when facing downstream.

Example: One Page 1 can be used for the inspection of any combination of assemblies in

a lock gate. If the upper right gate leaf is inspected, RIGHT LEAF should be circled in

the row labeled UPPER GATE. The gate type should also be indicated by circling the

appropriate type. The order of power transfer of the assemblies in the structure should be

numbered; for example, in Figure 5 the order is (1) Hydraulic Cylinder, (2) Rack, (3)

Exposed gear, and (4) Strut. The numbering for this example is shown below.

ASSEMBLY LIST AND ORDER OF POWER TRANSFER

COMMON LEFT RIGHT

Exposed gear 3 

Enclosed gear 

Gear rack 2 

Strut arm 4 

Rocker arm 

Cable 

Chain 

Hydraulic cylinder 1 

Coupling 
24

U. S. ARMY CORPS OF ENGINEERS PAGE 1

LOCK GATE LEAF OPERATING EQUIPMENT INSPECTION

NAME OF CIVIL WORKS PROJECT:

 

 

LOCATION OF CIVIL WORKS PROJECT: (1. Body of water, 2. Nearest town)

1. 

2. 

INSPECTION DATE: INSPECTED BY: 

GATE IDENTIFICATION: (circle the correct gate, leaf, and type of gate)

Upper Gate 1. Left Leaf 2. Right Leaf

Lower Gate 1. Left Leaf 2. Right Leaf

GATE TYPE

1. Miter

2. Sector

3. Tainter

4. Vertical Lift

ASSEMBLY LIST AND ORDER OF POWER TRANSFER

 COMMON LEFT RIGHT

Exposed gear 

Enclosed gear 

Gear rack 

Strut arm 

Rocker arm 

Cable 

Chain 

Hydraulic cylinder 

Coupling 
25

H Y D R A U L IC C Y L IN D E R 1

P IS T O N R O D

R E A C T IO N R O L L E R S

RO LLER S UPPO RT

G E AR R AC K 2

S EC TO R G EAR 3

M IT E R G AT E

C O M P R E S S IO N S P R IN G

S T R U T P IN AT S E C T O R A R M

S T RU T ARM 4

RO LLER S UPPO RT

S EC TO R ARM

S T R U T P IN AT G A T E

Figure 5. Plan view of miter lock gate operating equipment.

Page 1. Comments: Recordkeeping Data (continued)

The appropriate inspection Parts 1 and 2 for the selected assemblies will then be

completed and combined with pages 1 and 2 for a complete set of inspection forms. If

the gate shown in Figure 5 were inspected, one hydraulic cylinder Parts 1 and 2, one gear

rack Parts 1 and 2, one exposed gear Parts 1 and 2, and one strut page must be added to

the pages 1 and 2 for a complete set. 
26

U. S. ARMY CORPS OF ENGINEERS PAGE 2

LOCK GATE LEAF OPERATING EQUIPMENT INSPECTION

IS ORIGINAL OPERATION EQUIPMENT IN PLACE? (Y/N) 

IF NOT, IDENTIFY CURRENT OPERATION EQUIPMENT HISTORY: 

 

ARE DRAWINGS AVAILABLE FOR EQUIPMENT IN PLACE? (Y/N) 

ARE THE DRAWINGS INCLUDED WITH THIS FILE? (Y/N) 

PAST 10 YEAR HISTORY

MAJOR MAINTENANCE, REPAIRS, OR OTHER MODIFICATIONS

 DATE DESCRIPTION 

(1): 

(2): 

(3): 

(4): 

PREVIOUS INSPECTIONS OR STRUCTURAL REVIEWS (attach available copies)

 DATE DESCRIPTION 

(1): 

 

(2): 

(3): 

(4): 

OTHER COMMENTS:

 
27

Page 2 comments: Historical or General Data.

Completed before the site inspection and verified or changed during the site inspection.

Operating equipment components are sometimes replaced or removed during

rehabilitation. It is important for later reference to record the history of the in-place

structure.

Enter major MAINTENANCE, REPAIRS, OR OTHER MODIFICATIONS performed

on the operating equipment within the past 10 years.

Enter PREVIOUS INSPECTION information for reference purposes.
28

U. S. ARMY CORPS OF ENGINEERS PAGE 1

VALVE OPERATING EQUIPMENT INSPECTION

NAME OF CIVIL WORKS PROJECT:

 

 

LOCATION OF CIVIL WORKS PROJECT: (1. Body of water, 2. Nearest town)

1. 

2. 

INSPECTION DATE: INSPECTED BY: 

VALVE IDENTIFICATION: (circle the correct valve and type of valve)

Filling Valve 1. Left Valve 2. Right Valve

Emptying Valve 1. Left Valve 2. Right Valve

VALVE TYPE

1. Tainter 

2. Butterfly

3. Vertical lift

ASSEMBLY LIST AND ORDER OF POWER TRANSFER

 COMMON LEFT RIGHT

Exposed gear 

Enclosed gear 

Gear rack 

Strut arm 

Rocker arm 

Cable 

Chain 

Hydraulic cylinder 

Coupling 
29

Page 1. Comments: Recordkeeping Data

Completed before the site inspection and verified or changed during the site inspection.

Enter the NAME of the Corps of Engineer Project Title.

Indicate the BODY OF WATER and NEAREST TOWN.

Indicate VALVE IDENTIFICATION. Circle the valve that will be inspected and the

TYPE of VALVE. The orientation of the valve, left or right, is determined by looking

downstream.

Select ASSEMBLIES that exist in the operating equipment and number them in order of

POWER TRANSFER from source of the power to the structure. If the operating

equipment splits into a LEFT and RIGHT set of equipment, place the power transfer

number in the columns labeled left and right, respectively. Place an L behind the number

if it is on the left side and an R behind the number if it is on the right side. If the

assembly is common to (shared by) both sides or if there is no power split, place the

numbers in the COMMON column. Left and right are determined when facing

downstream.

Example: One Page 1 can be used for the inspection of any combination of assemblies in

a valve. If the right filling valve is inspected, the RIGHT VALVE of the FILLING

VALVE should be circled. The valve type should also be indicated by circling the

appropriate type. The order of power transfer of the assemblies in the structure should be

numbered; for example, the order in Figure 6 is (1) Hydraulic cylinder, (2) Rocker arm,

and (3) Strut. The numbering for this example is shown below.

ASSEMBLY LIST AND ORDER OF POWER TRANSFER

 COMMON LEFT RIGHT

Exposed gear 

Enclosed gear 

Gear rack 

Strut arm 3 

Rocker arm 2 

Cable 

Chain 

Hydraulic cylinder 1 

Coupling 
30

U. S. ARMY CORPS OF ENGINEERS PAGE 1

VALVE OPERATING EQUIPMENT INSPECTION

NAME OF CIVIL WORKS PROJECT:

 

 

LOCATION OF CIVIL WORKS PROJECT: (1. Body of water, 2. Nearest town)

1. 

2. 

INSPECTION DATE: INSPECTED BY: 

VALVE IDENTIFICATION: (circle the correct valve and type of valve)

Filling Valve 1. Left Valve 2. Right Valve

Emptying Valve 1. Left Valve 2. Right Valve

VALVE TYPE

1. Tainter 

2. Butterfly

3. Vertical lift

ASSEMBLY LIST AND ORDER OF POWER TRANSFER

 COMMON LEFT RIGHT

Exposed gear 

Enclosed gear 

Gear rack 

Strut arm 

Rocker arm 

Cable 

Chain 

Hydraulic cylinder 

Coupling 
31

P IS T O N R O D

H Y D R A U L IC

C Y L IN D E R 1

RO C KER ARM

AS S E M BLY 2

BAS E

UPPER 

G U ID E

L O W E R G U ID E

C O N N E C T IN G R O D 

T O P O F VALV E

L IF T IN G B R A C K E T

P IV O T P O IN T

AN C HO R AG E

E N D C O N N E C T IO N

C O M P R E S S IO N S P R IN G

P A C K IN G P L AT E

S TRU T ARM 3

Figure 6. Side view of tainter valve operating equipment.

Page 1. Comments: Recordkeeping Data (continued)

The appropriate inspection pages for the selected assemblies will then be completed and

combined with pages 1 and 2 for a complete set of inspection forms. If the valve shown

in Figure 6 were inspected, one hydraulic cylinder Parts 1 and 2, one rocker arm page,

and one strut arm page must be added to pages 1 and 2 for a complete set. 
32

U. S. ARMY CORPS OF ENGINEERS PAGE 2

VALVE OPERATING EQUIPMENT INSPECTION

IS ORIGINAL OPERATION EQUIPMENT IN PLACE? (Y/N) 

IF NOT, IDENTIFY CURRENT OPERATION EQUIPMENT HISTORY: 

 

ARE DRAWINGS AVAILABLE FOR EQUIPMENT IN PLACE? (Y/N) 

ARE THE DRAWINGS INCLUDED WITH THIS FILE? (Y/N) 

PAST 10 YEAR HISTORY

MAJOR MAINTENANCE, REPAIRS, OR OTHER MODIFICATIONS

 DATE DESCRIPTION 

(1): 

 

(2): 

(3): 

(4): 

PREVIOUS INSPECTIONS OR STRUCTURAL REVIEWS (attach available copies)

 DATE DESCRIPTION 

(1): 

 

(2): 

(3): 

(4): 

OTHER COMMENTS:

 

 
33

Page 2 comments: Historical or General Data.

Completed before the site inspection and verified or changed during the site inspection.

Operating equipment components are sometimes replaced or removed during

rehabilitation. It is important for later reference to record the history of the in-place

structure.

Enter major MAINTENANCE, REPAIRS, OR OTHER MODIFICATIONS performed

on the operating equipment within the past 10 years.

Enter PREVIOUS INSPECTION information for reference purposes.
34

U. S. ARMY CORPS OF ENGINEERS PAGE 1

DAM GATE OPERATING EQUIPMENT STRUCTURE INSPECTION

NAME OF CIVIL WORKS PROJECT:

 

 

LOCATION OF CIVIL WORKS PROJECT: (1. Body of water, 2. Nearest town)

1. 

2. 

INSPECTION DATE: INSPECTED BY: 

GATE IDENTIFICATION(circle the appropriate gate)

1. Tainter 

2. Vertical lift

3. Roller

ASSEMBLY LIST AND ORDER OF POWER TRANSFER

 COMMON LEFT RIGHT

Exposed gear 

Enclosed gear 

Gear rack 

Strut arm 

Rocker arm 

Cable 

Chain 

Hydraulic cylinder 

Coupling 
35

Page 1. Comments: Recordkeeping Data

Completed before the site inspection and verified or changed during the site inspection.

Enter the NAME of the Corps of Engineer Project Title.

Indicate the BODY OF WATER and NEAREST TOWN.

Indicate type of gate for the GATE IDENTIFICATION.

Select ASSEMBLIES that exist in the operating equipment and number them in order of

POWER TRANSFER from source of power to the structure. If the equipment splits into

a LEFT and RIGHT set of equipment, place the power transfer number in the columns

labeled left and right, respectively. Place an L behind the number if it is on the left side

and an R behind the number if it is on the right side. If the assembly is common to

(shared by) both sides or if there is no power split, place the numbers in the COMMON

column. Left and right are determined when facing downstream. 

Example: One Page 1 can be used for any combination of assemblies used to operate a

dam gate. The gate type should be indicated by circling the appropriate type. The order

of power transfer of the assemblies in the structure should be numbered; for example, the

order in Figure 7 is: (1) Coupling, (2) Enclosed gears, (3) Coupling, (4) Enclosed gears,

(5) Coupling, (6L) Exposed gears, (6R) Coupling, (7L) Cable, (7R) Coupling, (8R)

Exposed gears, and (9R) Cable. The numbering for this example is shown below.

ASSEMBLY LIST AND ORDER OF POWER TRANSFER

 COMMON LEFT RIGHT

Exposed gear 6L 8R 

Enclosed gear 2, 4 

Gear rack 

Strut arm 

Rocker arm 

Cable 7L 9R 

Chain 

Hydraulic cylinder 

Coupling 1, 3, 5 6R, 7R
36

U. S. ARMY CORPS OF ENGINEERS PAGE 1

DAM GATE OPERATING EQUIPMENT STRUCTURE INSPECTION

NAME OF CIVIL WORKS PROJECT:

 

 

LOCATION OF CIVIL WORKS PROJECT: (1. Body of water, 2. Nearest town)

1. 

2. 

INSPECTION DATE: INSPECTED BY: 

GATE IDENTIFICATION(circle the appropriate gate)

1. Tainter 

2. Vertical lift

3. Roller

ASSEMBLY LIST AND ORDER OF POWER TRANSFER

 COMMON LEFT RIGHT

Exposed gear 

Enclosed gear 

Gear rack 

Strut arm 

Rocker arm 

Cable 

Chain 

Hydraulic cylinder 

Coupling 
37

C o u p lin g 1

E n c lo s e d R e d u c tio n

G e a r 2 (T ra n s fe r B o x )

C o u p lin g 3

E n c lo s e d R e d u c tio n 

 G e a r 4

C o u p lin g 5 

C o u p lin g 6 R

C o u p lin g 7 R

E x p o s e d R e d u c tio n 

 G e a r 8 R 

C a b le 9 R

C a b le 7 L

E x p o s e d R e d u c tio n

 G e a r 6 L

D o w n s tre a m

O u tp u t S h a ft

I n p u t S h a ft

Figure 7. Plan view of dam gate operating equipment.

Page 1. Comments: Recordkeeping Data

The appropriate inspection Parts 1 and 2 for the selected assemblies will then be

completed and combined with pages 1 and 2 for a complete set of inspection forms. If

the dam gate operating equipment shown in Figure 7 were inspected, five coupling pages,

two enclosed gear Parts 1 and 2, two exposed gear Parts 1 and 2, and two cable Parts 1

and 2 must be added to pages 1 and 2 for a complete set.
38

U. S. ARMY CORPS OF ENGINEERS PAGE 2

DAM GATE OPERATING EQUIPMENT INSPECTION

IS ORIGINAL OPERATION EQUIPMENT IN PLACE? (Y/N) 

IF NOT, IDENTIFY CURRENT OPERATION EQUIPMENT HISTORY: 

 

 

ARE DRAWINGS AVAILABLE FOR EQUIPMENT IN PLACE? (Y/N) 

ARE THE DRAWINGS INCLUDED WITH THIS FILE? (Y/N) 

PAST 10 YEAR HISTORY

MAJOR MAINTENANCE, REPAIRS, OR OTHER MODIFICATIONS

 DATE DESCRIPTION 

(1): 

 

(2): 

(3): 

(4): 

 

PREVIOUS INSPECTIONS OR STRUCTURAL REVIEWS (attach available copies)

 DATE DESCRIPTION 

(1): 

 

(2): 

(3): 

 

(4): 

 

OTHER COMMENTS:

 
39

Page 2 comments: Historical or General Data.

Completed before the site inspection and verified or changed during the site inspection.

Operating equipment components are sometimes replaced or removed during

rehabilitation. It is important for later reference to record the history of the in-place

structure.

Enter major MAINTENANCE, REPAIRS, OR OTHER MODIFICATIONS performed

on the operating equipment within the past 10 years.

Enter PREVIOUS INSPECTION information for reference purposes.
40

4 Exposed Gear Assembly

4.1 Component Identification

Definitions and sketches for components of the exposed gear assembly are

presented in the following paragraphs. Sector gears and bull gears, which are

used with the rack assembly on lock and dam gates, are included in this

assembly. The inspection form and rules for racks are presented in Chapter 6.

Sector Gear

A sector gear is a large gear in the shape of a partial circle. The gear

transfers force from the roller rack to a linkage arm through rotation (Figure 5). 

The linkage arm is secured to and rotates with the sector gear, which rotates on

either a bushing or bearing system. Sector gears often have counter weights or

are supported by a roller system to account for eccentric loads on the bushings or

bearings.

Bull Gear

The bull gear consists of teeth arranged in a circular fashion and transfers

force from the reduction gear set to the rack on a sector gate (Figure 8). The

gear rotates on either a bushing or a bearing system.

Reduction Gears

Reduction gears are a series of gears used to lessen the torque required to

open and close or raise and lower gate or valve structures, respectively. As a

result, the structure moves at a slower rate of speed then the motor rotates

(Figures 7, 8, and 9).

Gear and Pinion

The gear and pinion are a set of reduction gears, with the pinion

substantially smaller than the gear.
41

E L E C T R IC M O T O R

W ORM

W ORM

G EAR

R E D U C T IO N G E A R S S E C T O R G AT E

LO C K C HAMBER

R O LLER R AC K

LO C K W ALL

Figure 8. Plan view of sector lock gate operating equipment (gear and rack).

Roller Support

Large horizontal gears are often supported with roller systems.

4.2 Inspection Form With Comments

The following pages present Parts 1 and 2 of the field inspection forms for

an exposed gear assembly. The side-by-side arrangement of the opposing pages

displays specific explanations (right side) adjacent to the entry on the inspection

form (left side).
42

S HAFT TO MO TO R

W ORM

W O RM G EAR

S HAFT 

T H IR D 

R E D U C T IO N

FO U RT H 

R E D U C T IO N

G EAR

S EC OND

R E D U C T IO N

F IR S T 

R E D U C T IO N

S E C T IO N V IE W

W ORM

W O RM G EAR

S HAFT

S EC OND

R E D U C T IO N

T H IR D

R E D U C T IO N G EAR

F IR S T 

FO U RT H R E D U C T IO N

R E D U C T IO N

Figure 9. Reduction gear schematic.
43

Intentionally Blank
44

U.S. ARMY CORPS OF ENGINEERS P.T.#: 

EXPOSED GEAR INSPECTION PART 1

PROJECT NAME: 

DATE: 

GATE IDENTIFICATION: (identify the appropriate lock gate, valve, or dam gate)

Lock Gate

Upper 1. Left Leaf 2. Right Leaf

Lower 1. Left Leaf 2. Right Leaf

Valve

Emptying 1. Left 2. Right

Filling 1. Left 2. Right

Dam Gate

Number 

NOISE, JUMPING, & VIBRATION 

 IS IT NORMAL

NOISE: (Y/N) (Y/N) 

JUMPING: (Y/N) (Y/N) 

VIBRATION: (Y/N) (Y/N) 

 GEAR SET NUMBER

 1 2 3 4

ANCHORAGE MOVEMENT/DET.

MOVEMENT (Y/N): 

CORROSION (Y/N): 

CRACKED CONCR. (Y/N): 

EXPOSED BOLTS (Y/N): 

IF YES (Y), THEN IS THERE

 CORROSION (Y/N): 

 MISSING OR

 BROKEN NUTS (Y/N): 

 LOOSE NUTS (Y/N): 

 

 GEAR SET NUMBER

 1 2 3 4

 SMALL/LARGE GEAR: S L S L S L S L 

BEARING/BUSHING WEAR

 WOBBLE OR TIPPING 

IN THE GEAR (Y/N): 

IF YES, AND THE GEAR

IS BUSHING TYPE,

MEASURED LATERAL

DISPLACEMENT (JACKED): 

GEAR RADIUS(ft): 

COMMENTS: 

 
* This figure is on p 50.

45

PART 1 Comments: Field data

Enter the PROJECT NAME for this inspection, the DATE of the inspection, and, for the 

GATE IDENTIFICATION, identify which gate leaf or valve is being inspected. Also

enter the power transfer number (P.T.#), which can be found on Page 1 of the inspection

form.

Observation of the exposed gear during gate movement is a good indicator of problems. 

Record any indication of NOISE, JUMPING, and/or VIBRATION during operation and

then indicate whether this noise, jumping, and/or vibration is NORMAL.

Record the evidence of MOVEMENT of the gear ANCHORAGE system base as the gate

is opened and closed. Evidence of movement can be observed visually or enhanced by

placing a dial gage to monitor any movement (Figure 10).* A dial gage change greater

than 0.002 in. is considered movement. Excessive concrete spalling may indicate a

displacement occurred at this location at some time. Also, record the presence of any

CORROSION (10% volume loss) of the steel portion or any CRACKED CONCRETE at

the interface of the embedment (Figure 10). Small hairline cracks, probably caused by

thermal expansion or contraction of the concrete, should be ignored. Indicate if there are

any CORRODED (10% volume loss), MISSING OR BROKEN, or LOOSE NUTS at the

gear anchorage if the BOLTS are EXPOSED (Figure 10).

The presence of BEARING/BUSHING WEAR for the gear is determined by observing

whether there is WOBBLE or TIPPING of the gear. Record whether there is wobbling or

tipping of the gear. To check for wobble, watch the gear as it is operated. If the gear is

not too large, bearing/bushing wear can also be checked by prying the gear while it is not

being operated. Tipping of large horizontal gears can be observed by measuring the

vertical distance from a gear tooth to a reference point on the concrete floor, rotating the

gear to a closed position if it was open (or to an open position if it was closed) and

measuring from the reference point on the concrete floor to the corresponding tooth

directly above the reference point. For vertical gears, a horizontal reference point should

be established to determine if wobbling occurs. When using this method to determine

whether tipping occurs, the maximum lateral displacement in a bushing type gear is 1/16

in. per foot of radius and 1/16 in. per 3 ft of radius in a bearing type system. If the

measured vertical displacement is greater than these maximums, record a yes (Y) for

bearing/bushing wear. If the gear rotates on a BUSHING TYPE system and tipping is

evident, record the MEASURED LATERAL DISPLACEMENT found by JACKING the

gear. A detailed procedure for jacking the gear can be found in Appendix A. Also record

the GEAR RADIUS in feet.
46

ARMY CORPS OF ENGINEERS P.T.#: 

 

EXPOSED GEAR INSPECTION PART 2

 GEAR SET NUMBER: 

 1 2 3 4

SMALL/LARGE GEAR: S L S L S L S L 

ROLLER SUPPORT WEAR/DAMAGE

IS GEAR ROLLER

SUPPORTED(Y/N)? 

IF YES, DO ROLLERS 

TURN FREELY(Y/N)? 

IF THEY DO NOT TURN 

FREELY, IS THE GEAR

OPERATION LIMITED(Y/N)? 

CRACKS

 NUMBER OF CRACKS: 

 

REDUCED TOOTH CONTACT

 % CONTACT: 

CONTACT LOCATION 

 RADIAL DIRECTION

 (tip(T), middle(M), root(R)): 

 AXIAL DIRECTION

 (top(P), center(C), bottom(B)): 

TOOTH WEAR

WORN TEETH(Y/N): 

IF YES, ESTIMATE %

THICKNESS REDUCTION: 

IF GREATER THAN 10%,

MEASURED %: 

DAMAGED TEETH

 % OF DAMAGED 

SURFACE AREA: 

CHIPPED(H), DEFORMED(D),

CORRODED(C), PITTED(P),

OR GOUGED(G): 

LOCATION(tooth number): 

# OF DAMAGED TEETH: 

 

COMMENTS: 

 
* This figure is on p 50.

47

PART 2 Comments: Field data

Record a yes (Y) if the gear is ROLLER SUPPORTED. If the gear is roller supported,

record if the ROLLERS TURN FREELY. If the rollers do not turn freely, record if the

GEAR OPERATION IS LIMITED.

The presence of CRACKS on the gear is usually not tolerated. Record the NUMBER OF

CRACKS found on the gear by visual observation. Many times a crack will show up as

corrosion underneath the painted surface. Also record the location of the cracks in the

COMMENT section.

Record the average percentage of TOOTH CONTACT in the five teeth with the least

contact area. The contact area is usually associated with an area where the grease film is

noticeably thinner. Wear patterns may also help to identify the contact area. Once the

contact area has been identified, the % CONTACT is recorded as the percentage of the

total tooth area which is contacted area. Also, record where the CONTACT area

LOCATION is, relative to the total tooth area. In the RADIAL DIRECTION, the

location is recorded as occurring primarily at the tip (T), middle (M), root (R), or any

combination of the three (Figure 11).*

 In the AXIAL DIRECTION, the location is

recorded as occurring primarily on the top (P), center (C), bottom (B) or any combination

of the three (Figure 11). On horizontal gears, the top of the tooth is on the top side of the

gear. To determine the side of the tooth designated as the top on vertical gears, observe

the gear from both sides as the gate or valve is being closed. The side from which the

gear is turning counter-clockwise is the top side of the gear.

Pick the TOOTH with the worst WEAR and look at the wear at the pitch line. Record if

there is TOOTH WEAR. If the pitch line is not scribed on the teeth, a good estimate of

the pitch line location is slightly towards the tip from the mid-depth of the tooth. If tooth

wear is visible, estimate the PERCENTAGE of TOOTH THICKNESS REDUCTION. 

The percentage of thickness reduction can be estimated a number of ways. One technique

is to measure both a worn tooth and a tooth that has infrequent contact with a ruler or tape

measure and compare the tooth thicknesses. A second technique to estimate the

thickness reduction of tooth thickness on meshing gears with different widths is to check

for a worn ledge on the wider tooth, with the depth of the ledge being the estimate of

reduction in thickness. A third technique is to observe the curvature of a worn tooth and

a tooth that has infrequent contact. As the tooth wears, the tooth edge may become flat. 

If the estimated percentage is greater than 10%, record the MEASURED percentage using

wear measurement techniques in Appendix B. 

Pick the worst DAMAGED TOOTH for each type of damage on each gear and record the

percentage of SURFACE AREA that is missing due to CHIPPING, DEFORMATION,

PITTING, CORROSION, or GOUGING. If damage has occurred indicate the TYPE of

DAMAGE. Chipping of the tooth is the breaking off of steel pieces, which usually results in jagged edges and high stress concentrations in the tooth. Deformation of the tooth

is the changing of the shape of the tooth, usually the result of excessive forces or something becoming lodged between teeth during operation. Pitting of the tooth is the severe 
48

ARMY CORPS OF ENGINEERS P.T.#: 

 

EXPOSED GEAR INSPECTION PART 2

 GEAR SET NUMBER: 

 1 2 3 4

SMALL/LARGE GEAR: S L S L S L S L 

ROLLER SUPPORT WEAR/DAMAGE

IS GEAR ROLLER

SUPPORTED(Y/N)? 

IF YES, DO ROLLERS 

TURN FREELY(Y/N)? 

IF THEY DO NOT TURN 

FREELY, IS THE GEAR

OPERATION LIMITED(Y/N)? 

CRACKS

 NUMBER OF CRACKS: 

 

REDUCED TOOTH CONTACT

 % CONTACT: 

CONTACT LOCATION 

 RADIAL DIRECTION

 (tip(T), middle(M), root(R)): 

 AXIAL DIRECTION

 (top(P), center(C), bottom(B)): 

TOOTH WEAR

WORN TEETH(Y/N): 

IF YES, ESTIMATE %

THICKNESS REDUCTION: 

IF GREATER THAN 10%,

MEASURED %: 

DAMAGED TEETH

 % OF DAMAGED 

SURFACE AREA: 

CHIPPED(H), DEFORMED(D),

CORRODED(C), PITTED(P),

OR GOUGED(G): 

LOCATION(tooth number): 

# OF DAMAGED TEETH: 

 

COMMENTS: 

 

 
49

PART 2 Comments: Field data (continued)

localized corrosion of the tooth that results in small cavities in the tooth surface. 

Corrosion is the loss of steel in the tooth due to interaction with the environment. 

Gouging of the tooth is the occurrence of smooth grooves or holes in the tooth surface. 

Record the LOCATION of the damaged teeth. The location of the tooth is described by a

number. On a sector gear, the first tooth on the side where the sector arm is connected is

tooth number one and will be numbered from there. For bull gears that engage the sector

gate rack, the gear tooth that is fully in contact with the rack when the gate is in the open

position is numbered one and the remaining teeth will be numbered in counter-clockwise

direction from tooth one. For exposed reduction gears, the meshing tooth between the

gears that are fully in contact when the gate or valve is in the open position is numbered

one. The remaining teeth are numbered in order starting at tooth one and going in the

direction the gear turns as the gate or valve is being closed.
50

S EC TO R BAS E

(A N C H O R A G E )

RO LLER R AC K

S EC TO R G EAR AN C H O R AG E B O LT

D IA L G A G E

 C O R R O S IO N 

IN S P E C T IO N A R E A

C O N C R E T E S P A L L IN G 

 IN S P E C T IO N A R E A

Figure 10. Gear anchorage movement/deterioration measurement.

R oot

M id d le

T ip

T op

B o tto m

C e n te r

P itc h L in e

G e a r R o ta tio n D u rin g 

G a te O r V a lv e C lo s in g

Figure 11. Tooth contact location.
51



4.3 Condition Index

The following section contains the rules for calculating the individual CIis and

the assembly CIs for the exposed gear assembly. Distress descriptions and example

illustrations are also provided.

Noise, Jumping, and Vibration

Definition and causes. This distress represents abnormal sounds and motions

of the exposed gear assembly during operation. Although a noise is often difficult to

isolate and diagnose, abnormal noises should not be ignored because they commonly

indicate a problem. Abnormal noises, jumping, and vibrations are caused by several

factors including improper lubrication and misalignment of the exposed gear

assembly. Obviously, this distress is more subjective and less quantifiable than many

distresses; however, its importance should not be minimized. Jumping, for example,

can indicate the presence of an assembly problem. Abnormal noises almost always

indicate behavior that should be investigated.

Measurement and Limits. The noise, jumping, and vibration distress is

recorded when it occurs at any point in the operation sequence. The CI for the

possible combinations is:

Noise, Jumping, or Vibration CI

None 100

Yes for any one of the three 70

Yes for any two of the three 40

Yes for all three 30

Example: During the operation of an exposed gear assembly, a grinding sound

could be heard. The CI for the noise, jumping, and vibration distress is: 

because the grinding sound is abnormal for an exposed gear assembly. Table 2

shows this CI to be Good.

Anchorage Movement/Deterioration

Definition and causes. Anchorage movement and deterioration represents the

displacement of the embedded anchorage system and the current condition of the

assembly components, especially the gear casting and anchorage bolts. Movement
52

 

can occur during opening and closing of the gate or valve structure. The anchorage

system is the only mechanism that connects the gear to the concrete. Hence,

anchorage movement may indicate a significant structural problem, or it could

eventually introduce structural problems into other parts of the operating equipment

power transfer setup. In addition, corroded, loose, or missing casting and anchorage

bolts can cause irregular movement of the equipment introducing functional and

structural problems into various components.

Measurement and limits. If anchorage movement is detected visually or if a

movement of 0.002 in. or greater is registered on the dial gage, the movement is

considered significant. Any movement reduces the CI to 40. Any structural cracking or spalling of the concrete in this area will reduce the CI by a factor of 0.85

(Figure 10). This is also the case for a corroded embedment at this location (e.g., an

additional 0.85 reduction). In addition, if any of the exposed bolts or nuts are

significantly corroded, the CI is decreased by a factor of 0.70. If any of the anchor

or casting nuts are loose, the CI is decreased by a factor of 0.55. If any bolts or nuts

are broken or missing, the CI is decreased by a factor of 0.40. If an assembly has

multiple gear sets, the anchorage movement/deterioration CI for the assembly is the

minimum of the anchorage movement/deterioration CIs of the gear sets making up

that assembly.

Example: The anchorage for an exposed gear assembly had cracked concrete around

the anchorage base. In addition, some of the exposed bolts were significantly

corroded. No movement was detectable; therefore, the 

Table 2 describes this CI as Fair.

Bearing/Bushing Wear

Definition and causes. A bearing or bushing separates the axle and the gear.

The axle casting is rigidly attached to the anchorage system, while the bearing or

bushing is free to rotate. Bearing/bushing wear refers to the total relative movement

of the gear with respect to the axle. This wear can be caused by normal use, excessive forces, improperly aligned gears, or inadequate lubrication.

Measurement and limits. Wear in the bearing or bushing is determined by

observing the wobbling or tipping in the gear. If significant wobbling or tipping in a

gear is recorded (1/16 in. per foot of gear radius in a bushing system and 1/16 in. per

3 ft in a bearing system), the CI can be no higher than 70. If a “yes” is recorded for

wobbling or tipping and the gear rotates on a bushing type system, a vertical
53

 (4.1)





 

displacement, X, is recorded by a jacking procedure, as described in Appendix A. 

The limiting value for this vertical displacement is:

If an assembly has multiple gears, the bearing/bushing wear CI for the assembly is

the minimum of the CIs for bearing/bushing wear of the gears making up that

assembly.

Example: Tipping of a bushing type gear was detected. A vertical displacement of

was measured. The gear has a radius of 3 ft. The limiting value of the vertical

displacement for this gear is

The CI for bushing wear is

The CI is Marginal.

Roller Support Wear/Damage

Definition and causes. The roller support distress refers to the wear or

corrosion of the bearing or bushing system for the gear roller supports, if they exist. 

Wear or corrosion of the roller bearing or bushing can cause the roller to freeze and

become incapable of rolling. This distress can be caused by normal use, improper

alignment, or interaction with the environment.

Measurement and limits. Wear or corrosion in the rollers is determined by

observing whether the rollers turn freely during the operation of the equipment. If

the rollers do not turn freely, the CI is 70. If the roller damage affects the operation

of the gear, the CI is 40. If the exposed gear is not roller supported, no CI will be

calculated, and the CI for the exposed gear assembly will not be affected by the

roller support distress. If an assembly has multiple gears, the roller support wear/
54



 (4.2)

 

damage CI for the assembly is the minimum of the roller support wear/damage CIs

of the gears making up that assembly.

Example: During the operation of a roller supported exposed gear, the rollers did

not turn freely. The CI for the roller support distress is

The CI is rated Marginal.

Cracks

Definition and causes. Cracks usually represent a narrow opening, break, or

discontinuity in the steel members. Cracks are caused by fatigue, brittle fracture, or

overstressed steel components. Obviously, cracks have significant structural

implications because they can continue to grow if the cause of the overstress still

exists or if the remaining steel cross section cannot carry the normal loads.

Measurement and limits. The number of cracks on the teeth and frame of the 

gear are recorded on the inspection form. The limiting value for a exposed gear is

one crack:

which is considered critical. A crack on the gear reduces the CI to 40. If an

assembly has multiple gears, the cracks CI for the assembly is the minimum of the

cracks CIs of the gears making up that assembly.

Example: One crack was found on an exposed gear during an inspection. The CI

for this distress is:

The CI is rated Marginal.
55

 





  

 

Reduced Tooth Contact

Definitions and causes. The tooth contact distress is the reduction in contact

area or engagement surface between meshing teeth. This distress can be caused by

normal wear, uneven wear, or misalignment of gears.

Measurements and limits. The percent of contact, X1 , is found by observing

the grease on the face of the gear teeth. The percent of tooth not in contact is:

The limiting value for the percentage of noncontact on gear teeth is:

If an assembly has multiple gears, the reduced tooth contact CI for the assembly is

the minimum of the reduced tooth contact CIs of the gears making up that assembly.

Example: The percentage of contact on a gear tooth was:

The percentage of the tooth not in contact was:

The CI for tooth contact is:

The CI is rated Fair.

Tooth Wear

Definition and causes. Tooth wear is the deterioration of gear teeth as

corresponding teeth engage. The causes of this distress can be attributed to normal

wear, inadequate lubrication, excessive loads, and improper gear alignment. 

Appendix B describes gear tooth wear measuring procedures.
56

 (4.5)



 





Measurement and limits. Gear tooth wear will be measured by recording the

estimated or measured percentage of tooth thickness loss at the pitch line, X . The

limiting value is:

If an assembly has multiple gears, the tooth wear CI for the assembly is the minimum of the tooth wear CIs of the gears making up that assembly.

Example: The percentage of lost thickness of a gear tooth at the pitch line measured

during an inspection was:

The CI (from Equation 2.1) is:

The CI is rated Fair.

Damaged Teeth

Definitions and causes. Stress in gear teeth increases as the surface area is

decreased or stress concentrations are introduced. Damage to teeth may lead to

failure because of the reduction in surface area and the introduction of stress

concentrations. This distress could be caused by factors including improper

lubrication, excessive force on teeth, or misalignment of teeth.

Measurements and limits. The percentage of lost surface area on gear teeth,

X, is recorded in the inspection process. The limiting value for damaged teeth

depends on the type of damage. In cases where the tooth has been chipped or

deformed, the limiting value is:

If the tooth is corroded, pitted, or gouged, the stress concentrations will be lower and

the limiting value is:
57



 

If an assembly has multiple gears, the damaged teeth CI for the assembly is the

minimum of the damaged teeth CIs of the gears making up that assembly.

Example: The percent of contact area that was chipped on a gear tooth was:

The CI for damaged gear teeth is:

The CI is rated Marginal.

Assembly CI

The assembly CI will be calculated with Equations 2.2, 2.5, and 2.6 (see

Chapter 2, Assembly Distress). The lone critical distress in the exposed gear

assembly is the cracks distress. The CIi

s from the remaining seven distresses will be

used to calculate the weighting factor assembly CIw (Equation 2.5). The weighting

factors for those seven distresses are in Table 12.

4.4 Field Test

Twenty exposed gear assemblies were observed during the field tests. The bar

charts in Figures 12, 13, and 14 compare the experts' subjective CI during the

various field tests with the CI calculated from the rules in Section 4.3 for three

exposed gear distresses. Assemblies with no distresses are not plotted. Comparisons between the calculated and experts’ CIs are summarized in the remainder of

this chapter.
58

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

100

S.L. DT 1 S.L. LS UR

CONDITION INDEX

Model Exp. Avg. Exp. Max. Exp. Min.

Figure 12. Anchorage movement/deterioration: exposed gear assembly.

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

100

O LS UL N LM UR C LM UR

CONDITION INDEX

Model Exp. Avg. Exp. Max. Exp. Min.

Figure 13. Bearing/bushing wear: exposed gear assembly.
59

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

100

S.L. LS UR S.L. DT1 S.L. DT4 S.L. DT7 C LS UR G.2 LM UR G.2 LM LR

CONDITION INDEX

Model Exp. Avg. Exp. Max. Exp. Min.

Figure 14. Reduced tooth contact: exposed gear assembly.

Noise, Jumping, and Vibration

Because no abnormal noise, jumping, or vibration was recorded, the calculated

CI values were 100. Although this distress was not recorded, the experts’ average

was below 90 on three of sixteen assemblies that were rated. However, in each of

these three cases the experts’ average was 85 or greater. The noise, jumping, and

vibration distress was calibrated in the enclosed gear assembly and the calculated

CIs closely approximated the experts’ average CIs.

Anchorage Movement/Deterioration: Figure 12

The anchorage movement/deterioration distress was observed only twice on

the operating equipment field tests in exposed gear assemblies. Corroded nuts were

observed on an exposed reduction gear set (Tainter Dam Gate St. Lucie #1), and

anchorage movement was observed on a bull gear (Upper Right Sector Lock Gate

St. Lucie). The calculated CI for a corroded nut (85) closely approximates the

experts’ average CI (86). The calculated CI for anchorage movement (40) is significantly lower than the experts’ average (75) for the one observed case. In later

conversation with the experts, some said they had not rated the distress lower

because they felt it could be fixed by merely tightening the bolts. They did agree,

however, that the CI should have been lower than 75 if the problem was not fixed. 

For the remainder of the exposed reduction gear assemblies that were observed, the

calculated CIs were 100 and the experts’ average CIs were above 90.
60

Bearing/Bushing Wear: Figure 13

The bearing/bushing distress was observed once (Ortona Upper Left Lock

Gate) during the field tests using the current rules. In this case, the calculated CI

was 70 and the experts’ average CI was 89. In two other cases bushing wear was

observed using the jacking technique described in Appendix A (Newburgh Upper

Right Miter Lock Gate and Cannelton Miter Lock Gate Main Chamber). For these

cases, the calculated CIs (70 and 70), respectively, and the experts’ average CIs (68

and 80), respectively, are in better agreement.

Roller Support Wear/Damage

The roller support wear/damage distress was not calibrated because no damage

to any roller supports was observed in the exposed gears. Hence, the calculated CIs

were all 100 and the experts’ average CIs were 90 or above.

Cracks

The cracks distress was not calibrated because no cracks were observed in the

exposed gears. Hence, the calculated CIs were all 100 and the experts’ average CIs

were 90 or above. Although this distress was not calibrated, the experts feel that

cracks in the gear are critical and should be repaired, which corresponds well to

Section 4.3.

Reduced Tooth Contact: Figure 14

The reduced tooth contact and tooth wear distresses were initially combined as

one distress. Discussion with the experts near the end of the Louisville District field

test resulted in separating the initial distress into two distinct distresses —tooth

contact and tooth wear. Although no data was collected after the separation of the

distresses, the data collected for the original combined distress was used to calibrate

the tooth contact distress. This is appropriate for two reasons: (1) the observed

wear of the gear teeth was relatively low, and (2) the weighting factor given by the

experts for tooth contact was significantly higher than the weighting factor for tooth

wear (Table 12). In three cases (Tainter Dam Gate #4 St. Lucie, Miter Lock Gate

Upper Right Cannelton, and Miter Gate Upper Right Green River #2) where the

tooth contact distress was observed, the calculated CIs were lower than the experts’

average CIs. However, in all three cases the calculated CIs were in Zone 2. In the

other four cases, the calculated CIs corresponded well with the expert averaged CIs.
61

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

100

O DV 4

CONDITION INDEX

Model Exp. Avg. Exp. Max. Exp. Min.

Figure 15. Exposed gear assembly CI.

Tooth Wear

Discussion with the experts near the end of the Louisville District field test

resulted in a separation of the tooth wear and tooth contact distresses (see previous

paragraph). Therefore, while the tooth wear distress was observed, calibration of the

new rules is not possible with the current data. The new rules for tooth wear have,

however, been constructed using the experts' judgement and advice.

Damaged Teeth

The inspection form questions and rules for the damaged teeth distress have

changed significantly since the first field test. The current questions and rules were

formulated during discussion with experts following the second field test. 

Therefore, while damaged teeth were observed, calibration of the new rules is not

possible with the current data. The new rules for damaged teeth have, however,

been constructed using the experts' judgement and advice.

Assembly CI: Figure 15

The assembly CI for exposed gear assembly was calibrated for three

assemblies. In each case, the model CI was somewhat higher than the experts’

average CI. Although the model CIs were higher, the experts’ average CIs and the

model CIs were all in Zone 1.
62

5 Enclosed Gear Assembly

5.1 Component Identification

Definitions and sketches for components of enclosed gear are presented in the

following paragraphs.

Reduction Gears

Reduction gears are a series of gears used to lessen the torque required to open

and close or raise and lower gate or valve structures, respectively. As a result, the

structure moves at a slower rate of speed than the motor rotates (Figures 7 and 8). 

Enclosed reduction gears are in a gear box and can sometimes be seen by removing

the cover plate. The gears in the gear box are lubricated with an oil or grease bath.

Gear and Pinion

The gear and pinion are a set of reduction gears, with the pinion substantially

smaller than the gear.

Transfer Box

The transfer box is a set of reduction gears that redirects the rotating shaft by

90 degrees (Figure 7). This is accomplished with the use of a worm and a worm

gear (Figure 9) or with bevel gears.

5.2 Inspection Form With Comments

The following pages are Parts 1 and 2 of the field inspection forms for an

enclosed gear assembly. The side-by-side arrangement of the opposing pages

displays specific explanations (right side) adjacent to the entry on the inspection

form (left side).
63

Intentionally blank
64

U.S. ARMY CORPS OF ENGINEERS P.T.#: 

ENCLOSED GEAR INSPECTION PART 1

PROJECT NAME: 

DATE: 

GATE IDENTIFICATION: (identify the appropriate lock gate, valve, or dam gate)

Lock Gate 

Upper 1. Left Leaf 2. Right Leaf

Lower 1. Left Leaf 2. Right Leaf

Valve

Emptying 1. Left 2. Right

Filling 1. Left 2. Right

Dam Gate

Number 

NOISE, JUMPING, & VIBRATION IS IT NORMAL

NOISE (Y/N) (Y/N) 

JUMPING (Y/N) (Y/N) 

VIBRATION (Y/N) (Y/N) 

ANCHORAGE MOVEMENT/DETERIORATION

MOVEMENT: (Y/N) 

CORROSION: (Y/N) 

CRACKED CONCR.: (Y/N) 

EXPOSED BOLTS: (Y/N) -----> IF YES (Y), THEN IS THERE

CORROSION: (Y/N) 

MISSING OR

BROKEN NUTS: (Y/N) 

LOOSE NUTS: (Y/N) 

REDUCTION SET NUMBER

 1 2 3 4

SMALL/LARGE GEAR: S L S L S L S L 

CRACKS

CAN THE GEAR BE 

 OBSERVED (Y/N)? 

 IF YES, NUMBER OF CRACKS: 

DAMAGED TEETH

 CAN THE GEAR TEETH

 BE OBSERVED (Y/N)? 

 IF YES,

 % OF DAMAGED 

 SURFACE AREA: 

 CHIPPED(H), DEFORMED(D),

 CORRODED(C), PITTED(P),

 OR GOUGED(G): 

 LOCATION(tooth number): 

 # OF DAMAGED TEETH: 

COMMENTS: 

 
65

PART 1 Comments: Field data

Enter the PROJECT NAME for this inspection, the DATE of the inspection, and, for the

GATE IDENTIFICATION, identify which gate leaf or valve is being inspected. Also

enter the power transfer number (P.T.#), which can be found on Page 1 of the inspection

form. 

Observation of the enclosed gear during gate or valve movement is a good indicator of

problems. Record any indication of NOISE, JUMPING, and/or VIBRATION during

operation and then indicate whether this noise, jumping, and/or vibration is NORMAL.

Record the evidence of MOVEMENT of the gear ANCHORAGE system base of the gear

as the gate is opened and closed. Evidence of movement can be observed visually or

enhanced by placing a dial gage to monitor any movement (Figure 10). A dial gage

change greater than 0.002 in. is considered movement. Excessive concrete spalling may

indicate a displacement occurred at this location at some time. Also, record the presence

of any CORROSION (10% volume loss) of the steel portion or any CRACKED

CONCRETE at the interface of the embedment (Figure 10). Small hairline cracks,

probably caused by thermal expansion or contraction of the concrete, should be ignored. 

Indicate if there are any CORRODED (10% volume loss), MISSING OR BROKEN, or

LOOSE NUTS at the gear anchorage if the BOLTS are EXPOSED (Figure 10).

The presence of CRACKS on the gear is usually not tolerated. Sometimes a cover plate

can be removed and the gears can be observed. If the GEARS CAN BE OBSERVED,

record the NUMBER OF CRACKS found on the gear by visual observation. Many times

a crack will show up as corrosion underneath the painted surface. Also record the

location of the cracks in the COMMENT section. 

Sometimes a cover plate on the gear box can be removed and the gear teeth can be

observed. If the GEAR TEETH CAN BE OBSERVED, pick the worst DAMAGED

TOOTH for each type of damage on each gear and record the percentage of SURFACE

AREA, which is missing due to CHIPPING, DEFORMATION, PITTING,

CORROSION, or GOUGING. If damage has occurred indicate the TYPE of DAMAGE. 

Chipping of the tooth is the breaking off of steel pieces, which usually results in jagged

edges and high stress concentrations in the tooth. Deformation of the tooth is the

changing of the shape of the tooth, usually the result of excessive forces or something

becoming lodged in between teeth during operation. Pitting of the tooth is the severe

localized corrosion of the tooth that results in small cavities in the tooth surface. 

Corrosion is the loss of steel in the tooth due to interaction with the environment. 

Gouging of the tooth is the making of smooth grooves or holes in the tooth surface. 

Record the LOCATION of the damaged teeth. The location of the tooth is described by a

number. The meshing tooth between the gears that are fully in contact when the gate or

valve is in the open position is numbered one. The remaining teeth are numbered in order

starting at tooth one and going in the counter-clockwise direction. The counter-clockwise

direction is determined as the gate or valve is being closed. 
66

U.S. ARMY CORPS OF ENGINEERS P.T.#: 

ENCLOSED GEAR INSPECTION PART 2

OIL CONDITION

SLIGHT TEMPERATURE RISE OF GEAR BOX: (Y/N) 

SIGNIFICANT TEMPERATURE RISE OF GEAR BOX: (Y/N) 

EVIDENCE OF RECENT OIL LEAKAGE: (Y/N) 

NUMBER OF OIL DROPS PER CYCLE: 

WATER PRESENT IN OIL: (Y/N) 

RUST/DIRT PRESENT IN OIL: (Y/N) 

METAL PRESENT IN OIL: (Y/N) 

HAS OIL SAMPLE BEEN TAKEN? (Y/N) 

IF YES, DATE IT WAS TAKEN: 

DOES THE OIL MEET SPECIFICATIONS: (Y/N) 

COMMENTS: 

 
67

PART 2 Comments: Field data

Excessive TEMPERATURE RISE of THE GEAR BOX is often an indication that

something is not operating properly. A temperature rise can be observed by placing a

hand on the gear box during operation. Record if there is a SLIGHT or SIGNIFICANT

TEMPERATURE RISE of THE GEAR BOX. Record if there is EVIDENCE OF

RECENT LEAKAGE. Record the NUMBER of OIL DROPS that leak from the gear box

during one operating CYCLE. One cycle for a lock gate or a valve is by opening and then

closing the structure or vice-versa. For a dam gate, one cycle is completed by opening

the gate 2 ft and then closing it. Record if any WATER is PRESENT in the OIL. Many

times water will appear as a milky ribbon throughout the oil. Record if any DIRT or

RUST is PRESENT in the OIL. Also record if any METAL is PRESENT IN the OIL. 

This can be accomplished by taking a small sample of oil and subjectively observing its

quality. Record if an OIL SAMPLE WAS TAKEN. If YES, record the DATE WHEN it

was last tested and if the OIL MEETS manufacturer SPECIFICATIONS.
68



5.3 Condition Index

The following section contains the rules for calculating the individual CIs

for the enclosed gear assembly distresses and the assembly CI. Distress

descriptions and example illustrations are also provided.

Noise, Jumping, and Vibration

See noise, jumping, and vibration for the exposed gear assembly (Chapter

4, p 51).

Anchorage Movement/Deterioration

See anchorage movement/deterioration for the exposed gear assembly

(Chapter 4, p 51).

Cracks

See cracks for the exposed gear assembly (Chapter 4, p 54).

Damaged Teeth

See damaged teeth for the exposed gear assembly (Chapter 4, 56).

Temperature Rise of Gear Box

Definition and causes. Excessive temperature change often indicates that

the enclosed gears are not operating properly. Excessive temperature change can

be caused by inadequate lubrication, misaligned gear teeth, or excessive loads on

the enclosed gear assembly.

Measurement and limits. The temperature change of the oil in the gear

box that can be felt with the hand is recorded. If a slight temperature rise is

observed, the CI is 70. If a significant temperature rise is observed, the CI is 40.

Example: During the operation of an enclosed gear, a slight temperature rise was

observed. The CI for the temperature rise of the gear box distress is:

The CI is rated Good.
69

 (5.1)

 

Oil Leakage

Definition and causes. Fresh oil stains, dripping oil, or standing oil are

signs of oil leakage. Oil leakage can indicate other problems in the operating

equipment or can be caused by worn seals or gaskets on the gear box.

Measurement and limits. The number of oil drips per operation cycle are

recorded in the inspection form. One cycle of a lock gate or a valve is

completed by opening and then closing the structure or vice-versa. For a dam

gate, one cycle is completed by opening the gate 2 ft and then closing it. If

drops of oil are observed leaking during the operation of the enclosed gear, the

limiting value of oil leakage per cycle is:

The presence of any puddled oil or oil stains is also recorded. If there is

evidence of recent oil leakage, the CI can be no higher than 85.

Example: A sheet of paper was placed below an enclosed gear box during its

operation. During one cycle, three drips of oil dropped to the paper. The CI for

the oil leakage distress is:

The CI is rated Marginal.

Oil Contamination

Definition and causes. All rotating equipment parts and machinery

require lubrication to function properly. Over time the oil becomes

contaminated and breaks down. The oil contamination distress is the reduction

of the useful life of the lubrication oil. The contamination of the oil is caused by

the collection of dirt, rust, water, and metal particles in the oil.

Measurement and limits. Oil distress is measured at two different levels. 

The first level involves visually checking the oil consistency for: (1) water, (2)

dirt or rust, and (3) metal. If water is present, the CI is reduced by a factor of

0.85. Likewise, if dirt or rust are present, a reduction factor of 0.85 is applied to

the CI. If metal is in the oil, the CI is 40. In the second level of inspection, a

representative sample is examined in the laboratory for extended chemical

analysis to check for particulates such as dirt, water, and rust on a more precise

scale. The results of this test should be included in any inspection report that is
70

 

generated. If the oil does not meet the specifications set by the manufacturer or

laboratory, the CI is 40.

Example: Upon inspection of a gear box, rust and water were found to be

present in

the oil. The CI for oil contamination is:

Table 2 describes the CI as Good.

Assembly CI

The assembly CI will be calculated with Equations 2.2, 2.5, and 2.6 (See

Chapter 2, Assembly Distress). The lone critical distress in the enclosed gear

assembly is the cracks distress. The CIs from the remaining six distresses will

be used to calculate the weighted CIw (Equation 2.5). The weighting factors for

those six distresses are in Table 13.

5.4 Field Test

Fifteen enclosed gear assemblies were observed during the field tests. The

bar charts in Figures 16 to 21 compare the experts' subjective CI to the CI

calculated from the rules in Section 5.3 for six enclosed gear distresses that were

observed during field tests. Comparisons between the calculated and experts’

CIs are summarized below.

Noise, Jumping, and Vibration: Figure 16

The calculated noise, jumping, and vibration CIs closely approximated the

experts’ averages. In 12 of the 15 observed exposed gear assemblies, this

distress was not observed; therefore, the calculated CIs were 100 and the

experts’ average CIs were above 90. In one case (Upper Right Lock Gate Moore

Haven), a thumping noise was heard in the gear box. The calculated CI was 70,

while the experts’ average CI was 80. In another case, jumping was observed

(Upper Right Lock Gate St. Lucie); therefore, the calculated CI was 70. The

experts’ average CI was 74. The enclosed gear used to operate Dam Gate #1 on

the St. Lucie Dam was observed to make a noise and vibrate. The calculated CI

for noise and vibration is 40. The experts’ average CI dropped to 51.
71

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

100

O LS UL N LM UR C LM UR

CONDITION INDEX

Model Exp. Avg. Exp. Max. Exp. Min.

Figure 16. Noise, jumping, and vibration: enclosed gear assembly.

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

100

G1 VT UR G2 VT LR

CONDITION INDEX

Model Exp. Avg. Exp. Max. Exp. Min.

Figure 17. Anchorage movement/deterioration: enclosed gear assembly.
72

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

100

N DT 1

CONDITION INDEX

Model Exp. Avg. Exp. Max. Exp. Min.

Figure 18. Damaged teeth: enclosed gear assembly.

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

100

SL LS LR SL DT 1

CONDITION INDEX

Model Exp. Avg. Exp. Max. Exp. Min.

Figure 19. Temperature rise of oil: enclosed gear assembly.
73

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

100

 WP LS UR WP LS LR O LS UL O LS LL M LS LR SL LS UR SL LS LR C EB R 

CONDITION INDEX

Model Exp. Avg. Exp. Max. Exp. Min.

Figure 20. Oil leakage: enclosed gear assembly.

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

100

 WP LS UR WP LS LR M LS UR M LS LR SL LS LR SL DT1 SL DT 7 N DT 1 

CONDITION INDEX

Model Exp. Avg. Exp. Max. Exp. Min.

Figure 21. Oil contamination: enclosed gear assembly.
74

Anchorage Movement/Deterioration: Figure 17

The anchorage movement/deterioration distress could be calibrated for only

two enclosed gear assemblies during the field tests as the distress was not observed

in the other assemblies during the field tests. Corroded anchorage nuts were

observed at one location (Upper Right Lock Gate Moore Haven), where a CI of 85

was calculated. The experts did not seem to consider the corrosion significant, as

their average CI was 94. Anchorage movement of a different anchorage system

(Lower Right Lock Gate St. Lucie) was detected, and a CI of 40 was calculated. The

experts’ average CI of 57 was significantly lower than 100; however, it was still 17

points higher than the calculated CI.

Cracks

The cracks distress was not calibrated because no cracks were observed in the

enclosed gears. Hence, the calculated CIs were all 100 and the experts’ average CIs

were 90 or above. Although this distress was not calibrated, the experts felt that

cracks in an enclosed gear were critical and should be repaired, which corresponds

well to Section 4.3.

Damaged Teeth: Figure 18

Only one case of damaged teeth in enclosed gears was observed (Dam Gate #1

Newburgh). In this case, the calculated CI of 80 closely approximated the experts’

average of 76.

Temperature Rise Of Oil: Figure 19

The temperature rise of oil was observed twice in the field testing of enclosed

gear assemblies (Lower Right Lock Gate St. Lucie and Tainter Dam Gate #1 St.

Lucie). In both cases, the calculated CI is 70. The experts’ average CI varied

greatly in the two cases. With a slight temperature rise of the reduction gear box on

the Lower Right Lock Gate, the experts’ average was 85, while the experts’ average

was 58 when a temperature rise occurred in the gear box on Tainter Dam Gate #1. 

The difference in the experts' CIs could be based on the difference in temperature

change in the two cases; that is, the temperature change in the second case was

greater.

Oil Leakage: Figure 20

The oil leakage distress was observed in eight of the 15 enclosed gear

assemblies. The calculated CIs approximations to the experts’ average CIs for this
75

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

100

O LS LL M LS UR M LS LR S.L. LS UR S.L. LS LR N DT 1

CONDITION INDEX

Model Exp. Avg. Exp. Max. Exp. Min.

Figure 22. Enclosed gear assembly.

distress were fairly close. The experts’ average CIs varied from 9 points below to 15

points above the calculated CIs.

Oil Contamination: Figure 21

The calculated CIs for the oil contamination distress closely approximated the

experts’ average CIs. Dirt or water was observed in eight of the 15 enclosed gear

assemblies. The experts’ average CIs varied from 10 points below to 6 points above

the calculated CIs of 85. Metal filings were observed in one of the gear boxes

(Tainter Dam Gate #1 St. Lucie). In this case, the calculated CI was 40 and, the

experts’ average CI was 53. In the remaining seven cases, the distress was not

observed, and the experts’ average CIs were all 90 or higher.

Assembly CI: Figure 22

The assembly CI for the enclosed gear assembly was calibrated for six

assemblies. For four of the assemblies, the model CIs were above the experts’

average CIs, and for the remaining two assemblies the model CIs were slightly

lower. In only one case (Tainter Dam Gate #1 Newburgh) was the model CI

significantly different from the experts’ average CI. The corresponding model CIs

and experts’ average CIs were in the same zone for each of the six calibrated

assemblies.
76

6 Gear Rack Assembly

6.1 Component Identification

Definitions and sketches for components of the gear rack assembly are

presented in the following paragraphs.

Rack

The rack consists of a set of teeth arranged in a linear or slightly curved

fashion. Teeth on the rack mesh with matching teeth on the corresponding gear. 

The rack transfers force from the hydraulic cylinder to the sector gear when used to

operate a miter gate (Figure 5). When used to operate a sector gate, the rack is

attached rigidly to the top of the gate and transfers force from a gear to the gate

(Figure 8). Racks are sometimes designed to perform as strut and rack assemblies

simultaneously. These rack/strut members are used to operate sector lock gates and

tainter dam gates.

Reaction Rollers

Reaction rollers resist the lateral load on the rack by the gear as the equipment

is operated (Figure 5). This lateral force is caused by the transfer of force from the

gear to the rack.

Roller Supports

Roller supports act as vertical and horizontal guides for the rack as it is

operated (Figure 5). Roller supports, unlike reaction rollers, do not resist large

forces. They are simply guides that ensure that the rack moves smoothly through the

operation cycle.

6.2 Inspection Form With Comments

The following pages are Parts 1 and 2 of the field inspection forms for the rack 

assembly. The side-by-side arrangement of the opposing pages displays specific

explanations (right side) adjacent to the entry on the inspection form (left side).
77

Intentionally Blank
78

U.S. ARMY CORPS OF ENGINEERS P.T.#: 

GEAR RACK INSPECTION PART 1

PROJECT NAME: 

DATE: 

GATE IDENTIFICATION: (circle the appropriate gate)

Lock Gate

Upper 1. Left Leaf 2. Right Leaf

Lower 1. Left Leaf 2. Right Leaf

Valve

Emptying 1. Left 2. Right

Filling 1. Left 2. Right

Dam Gate

Number 

NOISE, JUMPING, & VIBRATION IS IT NORMAL

NOISE (Y/N) (Y/N) 

JUMPING (Y/N) (Y/N) 

VIBRATION (Y/N) (Y/N) 

CRACKS LOCATION

NUMBER OF CRACKS: 

REDUCED TOOTH CONTACT

 % CONTACT: 

 CONTACT LOCATION

TOOTH DIRECTION(tip(T), middle(M), root(R)): 

LATERAL DIRECTION(top(P), center(C), bottom(B)): 

TOOTH WEAR

WORN TEETH(Y/N):_____ 

IF YES, ESTIMATE % OF WORN THICKNESS:_____ 

IF GREATER THAN 10%, MEASURED %:_____

DAMAGED TEETH

% OF DAMAGED SURFACE AREA: 

CHIPPED(H), DEFORMED(D), CORRODED(C), PITTED(P), OR GOUGED(G): 

LOCATION(tooth number): 

NUMBER OF DAMAGED TEETH: 

RACK ATTACHMENT DETERIORATION

CORROSION: (Y/N) 

MISSING OR BROKEN NUTS: (Y/N) 

LOOSE NUTS: (Y/N) 

COMMENTS: 

 
79

Part 1 Comments: Field data

Enter the PROJECT NAME for this inspection, the DATE of the inspection, and, for the

GATE IDENTIFICATION, identify which gate leaf or valve is being inspected. Also

enter the power transfer number (P.T.#), which can be found on Page 1 of the inspection

form.

Observation of the rack during gate movement is a good indicator of problems. Record

any indication of NOISE, JUMPING, and/or VIBRATION during operation and then

indicate whether this noise, jumping, and/or vibration is NORMAL.

The presence of CRACKS on the RACK is usually not tolerated. Record the NUMBER

OF CRACKS found by visual observation. Many times a crack will show up as

corrosion underneath the painted surface. Also record the LOCATION of the cracks.

Record the average percentage of TOOTH CONTACT in the five teeth with the least

contact area. The contact area is usually associated with an area where the grease film is

noticeably thinner. Wear patterns may also help to identify the contact area. Once the

contact area has been identified, the % CONTACT is recorded as the percentage of the

total tooth area that is contact area. Also, record where the CONTACT area LOCATION

is relative to the total tooth area. In the TOOTH DIRECTION, the location is recorded as

occurring primarily at the tip (T), middle (M), root (R), or any combination of the three

(Figure 11). In the LATERAL DIRECTION, the location is recorded as occurring

primarily on the top (P), center (C), bottom (B) or any combination of the three (Figure

11). On a horizontal rack, the top of the tooth is on the top side of the rack. On a

vertical rack, the side of the tooth defined as the top is identified by the gear with which it

meshes. As described in Chapter 4, the top side of the vertical gear is the side that is

turning counter-clockwise as the gate or valve is being closed. The top side of the rack

tooth is the side that meshes with the top side of the meshing gear tooth. 

Pick the TOOTH with the worst WEAR and look at the wear at the pitch line. Record if

there is TOOTH WEAR. If the pitch line is not scribed on the teeth, a good estimate of

the pitch line location is slightly towards the tip from the mid-depth of the tooth. If tooth

wear is visible, estimate the PERCENTAGE of TOOTH THICKNESS REDUCTION. 

The percentage of thickness reduction can be estimated a number of ways. One technique

is to measure both a worn tooth and a tooth that has infrequent contact at the pitch line

with a ruler or tape measure and compare the tooth thicknesses. A second technique to

estimate the thickness reduction of tooth thickness on meshing gear and rack with

different widths is to check for a worn ledge on the wider tooth, with the depth of the

ledge being the estimate of reduction in thickness. If the estimated percentage is greater

than 10%, record the MEASURED percentage using wear measurement techniques in

Appendix B. 

Pick the worst DAMAGED TOOTH for each type of damage on the rack and record the

percentage of SURFACE AREA that is missing due to CHIPPING, DEFORMATION,

PITTING, CORROSION, or GOUGING. If damage has occurred indicate the TYPE of

DAMAGE. Chipping of the tooth is the breaking off of steel pieces, which usually

results in 
80

U.S. ARMY CORPS OF ENGINEERS P.T.#: 

GEAR RACK INSPECTION PART 1

PROJECT NAME: 

DATE: 

GATE IDENTIFICATION: (circle the appropriate gate)

Lock Gate

Upper 1. Left Leaf 2. Right Leaf

Lower 1. Left Leaf 2. Right Leaf

Valve

Emptying 1. Left 2. Right

Filling 1. Left 2. Right

Dam Gate

Number 

NOISE, JUMPING, & VIBRATION IS IT NORMAL

NOISE (Y/N) (Y/N) 

JUMPING (Y/N) (Y/N) 

VIBRATION (Y/N) (Y/N) 

CRACKS LOCATION

NUMBER OF CRACKS: 

REDUCED TOOTH CONTACT

 % CONTACT: 

 CONTACT LOCATION

TOOTH DIRECTION(tip(T), middle(M), root(R)): 

LATERAL DIRECTION(top(P), center(C), bottom(B)): 

TOOTH WEAR

WORN TEETH(Y/N):_____ 

IF YES, ESTIMATE % OF WORN THICKNESS:_____ 

IF GREATER THAN 10%, MEASURED %:_____

DAMAGED TEETH

% OF DAMAGED SURFACE AREA: 

CHIPPED(H), DEFORMED(D), CORRODED(C), PITTED(P), OR GOUGED(G): 

LOCATION(tooth number): 

NUMBER OF DAMAGED TEETH: 

RACK ATTACHMENT DETERIORATION

CORROSION: (Y/N) 

MISSING OR BROKEN NUTS: (Y/N) 

LOOSE NUTS: (Y/N) 

COMMENTS: 

 
81

Part 1 Comments: Field data (continued)

jagged edges and high stress concentrations in the tooth. Deformation of the tooth is the

changing of the shape of the tooth, usually the result of excessive forces or something

becoming lodged in between teeth during operation. Pitting of the tooth is the severe

localized corrosion of the tooth that results in small cavities in the tooth surface. 

Corrosion is the loss of steel in the tooth surface due to interaction with the environment.

Record the evidence of RACK ATTACHMENT DETERIORATION. Record whether

there are any CORRODED (10% volume loss), MISSING OR BROKEN, or LOOSE

NUTS. If a sector gate is being inspected, the bolts attach the rack to the gate. If a miter

lock gate or dam gate is being inspected, the bolts connect the rack to the I-beam.
82

U.S. ARMY CORPS OF ENGINEERS P.T.#: 

GEAR RACK INSPECTION PART 2

IS THE RACK BEING INSPECTED BEING USED TO 

OPERATE A MITER LOCK GATE OR DAM GATE(Y/N)? 

IF YES, COMPLETE THE REMAINING QUESTIONS

*************************************************************************************

*****

GEAR/RACK DISPLACEMENT

OPEN CLOSED

JACKED APART(in.): 

JACKED TOGETHER(in.): 

RACK WEAR

WEAR ON THE REACTION ROLLER EDGE? (Y/N) 

IF YES, ESTIMATE THE WEAR(1/16, 1/8, 3/16, 1/4 in.): 

WEAR ON THE BOTTOM FLANGE? (Y/N) 

IF YES, ESTIMATE THE WEAR(1/16, 1/8, 3/16, 1/4 in.): 

EXCESSIVE BOW IN THE RACK? (Y/N) 

REACTION ROLLERS WEAR/DAMAGE

DO THE ROLLERS TURN FREELY WHEN NOT IN CONTACT WITH THE RACK? (Y/N)

DO ROLLERS WOBBLE? (Y/N) 

ARE ROLLERS CAUSING DAMAGE TO RACK? (Y/N) 

REACTION ROLLERS ANCHORAGE MOVEMENT/DETERIORATION

MOVEMENT: (Y/N) 

CORROSION: (Y/N) 

CRACKED CONCR.: (Y/N) 

EXPOSED BOLTS: (Y/N) -----> IF YES (Y), THEN IS THERE

CORROSION: (Y/N) 

MISSING OR 

BROKEN NUTS: (Y/N) 

LOOSE NUTS: (Y/N) 

*************************************************************************************

*****

COMMENTS 

 
83

PART 2 Comments: Field data

Record whether the RACK BEING INSPECTED IS USED TO OPERATE A MITER

LOCK GATE OR DAM GATE. If yes, the following questions should be answered.

Excessive lateral DISPLACEMENT of the ROLLER RACK is an indication that a

problem is developing in the equipment. The movement can be quantified by placing

permanent marks on the gear and rack (Figure 23). The distance between these two

points is recorded when the gear and rack are JACKED or pried APART and when

JACKED or pried TOGETHER. The pry bar is placed between the gear and the rack to

force the roller rack and gear apart and the first measurement is taken (Figure 23). A jack

can also be placed in a position to force the gear and roller rack apart. The second

measurement is taken after the pry bar or jack are placed on the opposite side and used to

force the gear and roller rack together. These measurements should be taken when the

gate is OPEN and CLOSED. The difference between these two measurements indicates

the “play” in the system. This measurement is not applicable to racks attached to sector

gates.

Record the evidence of WEAR ON THE REACTION ROLLER EDGE of the rack. If

there is wear, estimate the amount of wear to the nearest 1/16 in. Record the evidence of

WEAR ON THE BOTTOM FLANGE of the rack. If there is wear, estimate the amount

of wear to the nearest 1/16 in. Also record any evidence of BOW IN THE RACK. 

Record whether the REACTION ROLLERS TURN FREELY by hand WHEN NOT IN

CONTACT WITH the RACK. Indicate whether the reaction rollers WOBBLE. Also

record if the reaction ROLLERS ARE CAUSING DAMAGE TO the RACK.

Record the evidence of MOVEMENT of the REACTION ROLLERS ANCHORAGE 

base as the gate is opened and closed. Evidence of movement can be observed visually or

enhanced by placing a dial gage to monitor any movement. A dial gage change greater

than 0.002 in. is considered movement. Excessive concrete spalling may indicate a

displacement occurred at this location at some time. Also, record the presence of any

CORROSION (10% volume loss) of the steel portion or any CRACKED CONCRETE at

the interface of the embedment. Small hairline cracks, probably caused by thermal

expansion or contraction of the concrete, should be ignored. Indicate if there are any

CORRODED (10% volume loss), MISSING OR BROKEN, or LOOSE NUTS at the

reaction rollers anchorage if the BOLTS are EXPOSED.
84

S E C T IO N V IE W

RO LLER 

R AC K

S EC TOR 

G EAR

P RY BAR

AN C H O R AG E

S EC TOR 

G EAR

R O LLE R R AC K

R E A C T IO N R O L L E R S

P RY BAR

P ERMANENT MARKS

MEAS U RED

D IS T A N C E

FO RC E 

APART

P RY BAR

FO RC E TO G ET HER

JAC K O R P RY BAR 

M AY B E U S E D

F IR S T F O R C E A P A R T P L A N V IE W T HEN FO RC E TO G ET HER

R E F E R E N C E L IN E

Figure 23. Gear/rack displacement measurement.
85

6.3 Condition Index

The following section contains the rules for calculating the individual CIs

for the rack assembly distresses. Distress descriptions and example illustrations

are also provided.

Noise, Jumping, and Vibration

See noise, jumping, and vibration for the exposed gear assembly (Chapter

4, p 51).

Cracks

See cracks for the exposed gear assembly (Chapter 4, p 54).

Reduced Tooth Contact

See reduced tooth contact for the exposed gear assembly (Chapter 4, p 55).

Tooth Wear

See tooth wear for the exposed gear assembly (Chapter 4, p 55).

Damaged Teeth

See damaged teeth for the exposed gear assembly (Chapter 4, p 56).

Rack Attachment Deterioration

See anchorage movement/deterioration for the exposed gear assembly

(Chapter 4, p 51).

Gear/Rack Displacement

Definition and causes. Excessive lateral movement between the gear and

the rack may cause the contact between gear teeth and rack teeth to decrease. 

With decreased contact, the stress on the teeth may increase significantly. The

wear that causes this problem can be due to improper lubrication and jumping

and vibration during operation of the assembly.

Measurement and limits. Measurements are recorded when the rack is

moved to the right and left with a crow bar (pry bar) or a jack (Figure 23).
86

  (6.1)

 (6.2)





  

 

X1 = Measurement when jacked or pried apart

X2 = Measurement when jacked or pried together

The X movement is taken as the difference between these two measurements.

These measurements are taken twice, once with the gate opened and once with

the gate closed, and the largest X is used. The limiting value for this movement

is taken as:

Example: A gear and rack were pried apart. The measurement was:

The assembly was then pried together. This measurement was:

The displacement X is found by Equation 6.1.

The CI for gear and rack

displacement is:

The CI is rated Poor.

Rack Wear

Definitions and causes. Rack damage can be in the form of loss of steel

section or bowing of the rack. The loss of section can occur both on the reaction

roller edge and on the bottom flange of the rack. This wear is caused by

interaction with the rollers. Bowing of the rack can occur from excessive force

being applied to the rack.
87

 (6.3)



 

Measurements and limits. The amount of wear, X, on either the roller

edge or bottom flange of the roller rack is recorded in the inspection form. The

maximum of the two X values is used to calculate the CI. The limiting value for

rack wear is:

If bowing in the rack is evident, the CI shall be 70.

The CI for rack wear is the minimum of the CIs for wear and for bowing of the

rack.

Example: Wear on the bottom flange of a rack was

There was no noticeable wear on the reaction roller edge nor was there any

bowing of the rack. The CI for rack wear is

The CI is rated Fair.

Reaction Roller Wear/Damage

Definitions and causes. The bushings or bearings in reaction rollers can

freeze and stop rotating or in some cases wear and cause the rollers to wobble. 

Inadequate lubrication and interaction with the environment can cause seizing of

the bushings or bearings. Wobble in the reaction rollers can be caused by

regular use or inadequate lubrication.

Measurements and limits. The reaction rollers are checked to see if they

rotate freely when they are not in contact with the rack. If they do not rotate

freely, the CI for reaction rollers is 70. The rollers are also observed to see if

they wobble. If they wobble, the CI is 70. If the rollers are causing damage to

the rack the CI is 40.
88



Example: Wobble was observed in a reaction roller; therefore:

The CI is rated Good.

Reaction Roller Anchorage Movement/Deterioration

See anchorage movement/deterioration for the exposed gear assembly

(Chapter 4, p 51).

Assembly CI

The assembly CI will be calculated with Equations 2.2, 2.5, and 2.6 (See

Chapter 2, Assembly Distress). The lone critical distress in the gear rack

assembly is the crack distress. The CIs from the remaining distresses will be

used to calculate the weighted assembly CIw (Equation 2.5). For a rack used to

operate a sector lock gate, five distresses will be used to calculate the weighted

assembly CIw. The weighting factors for those distresses are in Table 14. For a

rack used to operate a miter lock gate or a dam gate, eight distresses will be used

to calculate the weighted assembly CIw. The weighting factors for those

distresses are in Table 15.

6.4 Field Test

The bar charts in Figures 24 and 25 compare the experts' subjective

condition index during the field tests to the condition index calculated from the

rules in Section 6.3 for two rack distresses. Only data from assemblies with

observed distresses are plotted. Comparisons between the calculated and experts'

CIs are summarized below.

Noise, Jumping, and Vibration

Because no abnormal noise, jumping, or vibration was recorded, the

calculated CI values were 100. Although this distress was not recorded, the

experts’ average was below 90 on three of seven assemblies that were rated. 

However, in each of these cases, the experts’ average CI was 85 or greater. The

noise, jumping, and vibration distress was calibrated in Chapter 5 for the

enclosed gear assembly and the calculated CIs closely approximated the experts’

averages.
89

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

100

 G1 LM UR G2 LM UR G2 LM LR C LM URM C LM URA

CONDITION INDEX

Model Exp. Avg. Exp. Max. Exp. Min.

Figure 24. Reduced tooth contact: gear rack assembly.

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

100

SL LS UR C ML URM G2 LM UR G2 LM LR

CONDITION INDEX

Model Exp. Avg. Exp. Max. Exp. Min.

Figure 25. Gear/rack displacement: gear rack assembly.
90

Cracks

The cracks distress was not calibrated because no cracks were observed in

sector gears or racks. Hence, the calculated CIs were all 100 and the experts’

average CIs were 90 or above. Although this distress was not calibrated, the

experts felt that cracks in the gear or rack were critical and should be repaired,

which corresponds well to Section 4.3.

Reduced Tooth Contact: Figure 24

The tooth contact and tooth wear distresses were initially combined as one

distress. Discussion with the experts near the end of the Louisville District field

test resulted in separating the original distress into two distinct distresses—tooth

contact and tooth wear. Although no data were collected after the separation of

the distresses, the data collected for the original combined distress was used to

calibrate the tooth contact distress. This is appropriate for two reasons: (1) the

observed wear of the rack teeth was relatively low on the observed gears, and (2)

the weighting factor for tooth contact was significantly higher than the weighting

factor for tooth wear (Tables 14 and 15). In two cases where the tooth

contact/wear distress was observed (Miter Lock Gate Upper Right Cannelton

and Miter Gate Upper Right Green River #2), the calculated CIs were lower than

the experts’ average CIs. In these cases, the calculated CIs were in Zone 2. In

two other cases, the calculated CIs corresponded well with the experts’ average

CIs.

Tooth Wear

During development, discussion with the experts resulted in a separation

of the tooth wear and tooth contact distresses. Therefore, while the tooth wear

distress was observed, calibration of the new rules was not possible with the

current data used in the calibration of the tooth contact distress. The new rules

for tooth wear were, however, constructed using the experts' judgement and

advice.

Damaged Teeth

The damaged teeth distress was not calibrated because no damaged teeth

were observed in the racks. Hence, the calculated CIs were all 100 and the

experts’ average CIs were 90 or above. The damaged teeth distress was

calibrated for the enclosed gear assembly (Section 5.4) and the calculated CIs

closely approximated the experts’ average CIs.
91

Rack Attachment Deterioration

The rack attachment deterioration distress was not calibrated because no

deterioration was observed in the rack attachment for sector gates. Hence, the

calculated CIs were all 100 and the experts’ average CIs were 90 or above. The

anchorage movement/deterioration distress was calibrated for the exposed gear

assembly (Section 4.4) and the enclosed gear assembly (Section 5.4). In each

case the calculated CIs closely approximated the experts’ average CIs.

Gear/Rack Displacement: Figure 25

The calculated CIs closely approximated the experts’ average on all but

two (Upper Right Lock Gate Green River 1 and Upper Right Lock Gate Main

Chamber Cannelton) of the sector gear and rack assemblies that were rated. In

both of these cases, the measured displacements were 3/16 in., which were the

largest displacements observed during the field tests. In both cases, the

calculated CI was well below the experts’ average CI. In each of the other sector

gear and rack assemblies where the displacements were smaller, the calculated

CIs matched well with the experts’ averages.

Rack Wear

The rack wear distress was not calibrated because rack wear was not

observed during the field tests. Hence, the calculated CIs were all 100 and the

experts’ average CIs were 90 or above.

Reaction Roller Wear/Damage

The reaction roller wear/damage distress was not calibrated because the

distress was not observed during the field tests. Hence, the calculated CIs were

all 100. The experts’ average CIs ranged between 83 and 92. The experts were

reluctant to rate the reaction rollers higher because they were not in perfect

working condition. Although the reaction rollers did turn freely when not

loaded, they were no longer in the condition they had been in when installed.

Reaction Roller Anchorage Movement/Deterioration

The reaction roller anchorage movement/deterioration distress was not

calibrated because no movement or deterioration of the anchorage was observed. 

Hence, the calculated CIs were all 100 and the experts’ average CIs were 90 or

above. The anchorage movement/deterioration distress was calibrated for the

exposed gear assembly (Section 4.4) and the enclosed gear assembly (Section
92

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

100

G1 LS UR G2 LS UR C LM UR

CONDITION INDEX

Model Exp. Avg. Exp. Max. Exp. Min.

Figure 26. Gear rack assembly CI.

5.4). In each case, the calculated CIs closely approximated the experts’ average

CIs.

Assembly CI: Figure 26

The assembly CI for the rack assembly was calibrated for three

assemblies. In each case the model CI was slightly higher than the experts’

average CI. Although the model CIs were higher, the experts’ average CIs and

the model CIs were all in the upper part of Zone 1.
93

7 Strut Arm Assembly

7.1 Component Identification

Definitions and sketches for components of the strut arm assembly are

presented in the following paragraphs.

Strut

The strut transfers force from one component to another. Its function when

used with a lock gate is to transfer force from the sector arm to the gate (Figure 5). 

The strut transfers force from the rocker arm assembly to the valve when used with a

valve structure (Figure 6).

Linkage Pin

The linkage pin serves as a pivot point for the strut (Figure 5). For lock gates,

one linkage pin serves as a pivot between the sector arm and the strut, and a second

pin serves as a pivot between the strut and the gate. Valve struts also have pins on

both ends.

Compression Spring

The compression spring is in the strut (Figures 5 and 6). Its function is to allow

the strut to shorten or lengthen slightly when the gates or valves are closed or lowered,

which provides a tight fit without damaging the structure. The compression spring

also acts as a shock absorber between the gate and the operating equipment.

End Connection

The end connection is fixed to the gate, sector arm, or valve and transfers

force from the strut to these structures or components (Figure 6).

7.2 Inspection Form With Comments

The following page is the field inspection form for the strut arm assembly.

The side-by-side arrangement of the opposing pages displays specific explanations

(right side) adjacent to the entry on the inspection form (left side).
94

U.S. ARMY CORPS OF ENGINEERS P.T.#: 

STRUT ARM INSPECTION

PROJECT NAME: 

DATE: 

GATE IDENTIFICATION: (indicate the appropriate gate)

Lock Gate

Upper 1. Left Leaf 2. Right Leaf

Lower 1. Left Leaf 2. Right Leaf

Valve

Emptying 1. Left 2. Right

Filling 1. Left 2. Right

Dam Gate

Number 

NOISE, JUMPING, & VIBRATION IS IT NORMAL

NOISE (Y/N) (Y/N) 

JUMPING (Y/N) (Y/N) 

VIBRATION (Y/N) (Y/N) 

END CONNECTION MOVEMENT

(estimate movement (in.): 0, 1/8, 1/4, 3/8, 1⁄2): OPEN CLOSED

POWER END: 

OTHER END: 

COMPRESSION SPRING MOVEMENT

DOES IT MOVE FREELY? (Y/N) 

IF NO, COULD LACK OF MOVEMENT DAMAGE EQUIPMENT? (Y/N) 

CORROSION

ORIGINAL SECTION THICKNESS(in.): 

SIGNIFICANT CORROSION: (Y/N)

SEVERE PITTING OR GENERAL THICKNESS REDUCTION: (Y/N) 

CRACKS

NUMBER OF CRACKS: 

LOCATION FROM POWER END (ft): 

COMMENTS: 

 
95

Comments: Field data

Enter the PROJECT NAME for this inspection, the DATE of the inspection, and, for the

GATE IDENTIFICATION, identify whether a lock gate, valve, or dam gate is being

inspected. Also enter the power transfer number(P.T.#), which can be found on Page 1 of

the inspection form.

Observation of the strut arm assembly during gate and valve movement is a good

indicator of problems. Record any indication of NOISE, JUMPING, and/or

VIBRATION during operation, and then indicate whether this noise, jumping, and/or

vibration is NORMAL.

Record the relative MOVEMENT in the END CONNECTION between the strut arm and

the attached component or structure. Estimate the movement to the nearest 1/8 in. To

further enhance the visual observation, place a dial gage at this location. Record the

readings while the operating equipment is in the OPEN and CLOSED positions. 

Movement should be recorded for both the POWER END and the OTHER END of the

strut arm (Figure 27). The END CONNECTION MOVEMENT at the bottom of the

valve strut is inspected during the valve inspection (leave OTHER END blank).

Record if the COMPRESSION SPRING is operating normally. Watch the structure as it

is opened and closed. The spring should MOVE FREELY at the beginning and end of

the stroke. During the closing of the structure, the compression spring should compress

at least 1⁄2 to 1 in. and should release when the force in the strut changes from

compression to tension. The compression spring should act as a shock absorber to soften

the loads transmitted to the operating machinery. If the compression spring does not

move freely, record whether LACK OF MOVEMENT COULD DAMAGE

EQUIPMENT or the structure. 

The presence of excessive CORROSION on the strut arm is a potential problem. Record

the WALL THICKNESS of the STRUT in order to better judge the corrosion. Obtain the

wall thickness from construction drawings. Record YES if there is SIGNIFICANT

CORROSION (more than general scaling). If yes, indicate if there is SEVERE PITTING

(1/8 in. pits or greater) in a dense pattern or GENERAL THICKNESS REDUCTION of

10% or greater in local areas.

The presence of CRACKS on the strut arm is usually not tolerated. Record the

NUMBER OF CRACKS found on these components by visual observation as well as the

LOCATION of the cracks with respect to the POWER END.
96

C ABLE

G AT E 

FRAME

L IF T IN G

BRAC KET

MEAS URE T HE 

R E L AT IV E 

MOVEMENT

G AT E 

FRAME

L IF T IN G

BRAC KET

C H A IN

MEAS URE T HE 

R E L AT IV E 

MOVEMENT

L IF T IN G 

BRAC KET

MEAS URE T HE 

R E L AT IV E

MOVEMENT

S TRUT

G AT E

C O N N E C T IN G P IN

S EC TO R ARM

S T RUT ARM

MEAS URE T HE 

R E L AT IV E 

MOVEMENT

Figure 27. End connection movement distress.
97

 (7.1)

 (7.2)





7.3 Condition Index

The following section contains the rules for calculating the individual CIs for

the strut arm assembly distresses. Distress descriptions and example illustrations are

also provided.

Noise, Jumping, Vibration

See noise, jumping, vibration for the exposed gear assembly (Chapter 4, p 51).

End Connection Movement

Definition and causes. The strut arms are connected to the sector gear or

valve with linkage pins. Over time, the pins and bushings wear due to normal

operation or improper lubrication. Relative movement is experienced due to the

wear in the linkage pins and the bushings. In some cases, the connection is designed

without a bushing. In this case, the wear occurs directly between the pin and the

strut arm.

Measurement and limits. End connection movement at the opened and closed

positions is visually observed and recorded to the nearest 1/8 in. The X value for

end connection movement is the relative movement between the end of the strut and

the structure to which it is attached. The greater of X1 and X2 at the two ends of the

strut arm is used to calculate the CI.

For valves, the end of the strut arm connected to the valve is inspected during the

valve inspection, in which case X is equal to the measurement at the power end. 

The limiting value for end connection movement is:

Example: The relative movement of the strut arm end connection at End 1 was:

and at End 2 was:
98

 

 



The value of X (by Equation 7.1) is:

The CI for the strut arm end connection movement is:

The CI is rated Marginal.

Compression Spring Movement

Definition and causes. The compression spring acts like a shock absorber as

the gate opens into the recess or closes for emptying or filling of the chamber. 

Normal compression spring movement occurs near the end of the opening and

closing cycles. Corrosion or other damage can cause the compression spring to lose

flexibility.

Measurement and limits. If the compression spring is not working properly,

but will not likely damage the other operating equipment, the CI is 70. If, however,

the compression spring is not working properly and could cause damage to the

structure and other operating equipment, the CI is 40.

Example: A compression spring did not move during the opening and closing of a

lock gate. The lack of movement created the potential for damage to occur to other

operating equipment. The CI for the compression spring is:

The CI is rated Marginal.

Corrosion

Definitions and causes. Corrosion involves the loss of steel material on the

strut arm assembly due to interaction with the environment. If this interaction

continues, pitting occurs. Pitting is the minor loss of steel in localized areas. While

light deterioration causes little structural problems, extensive corrosion can reduce

the cross-sectional area of the assembly, thereby increasing the stresses.

Measurements and limits. Corrosion that is more intensive than general

scaling is recorded. If corrosion is greater than scaling but pitting is less than 1/8 in.

and general thickness reductions are less than 10 percent, the CI is 70. If pitting is
99



1/8 in. or greater or a general thickness reduction of 10 percent or greater , the CI

should be reduced to 40.

Example: Corrosion of a strut arm was detected during an inspection. In several

local areas the general thickness reduction of the arm was 15 percent of its original

thickness.

The CI for corrosion is:

The CI is considered Marginal.

Cracks

See cracks for the exposed gear assembly (Chapter 4, p 54).

Assembly CI

The assembly CI will be calculated with Equations 2.2, 2.5, and 2.6 (See

Chapter 2, Assembly Distress). The lone critical distress in the strut assembly is the

crack distress. The CIs from the remaining four distresses will be used to calculate

the weighted CIw (Equation 2.5). The weighting factors for those four distresses are

in Table 16.

7.4 Field Test

The bar charts in Figures 28 and 29 compare the experts' subjective condition

index from the field tests to the condition index calculated from the rules in Section

7.3 for two strut arm distresses. Only data from assemblies with observed distresses

are plotted. Comparisons between the calculated and experts' condition indexes are

summarized below.

Noise, Jumping, Vibration

The noise, jumping, and vibration distress was not calibrated because the

distress was not observed in strut arms. Hence, the calculated CIs were all 100, and

the experts’ average condition indexes were 90 or above. The noise, jumping, and

vibration distress was calibrated for the enclosed gear assembly, and the calculated

CIs closely approximated the experts’ averages.
100

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

100

N LM UR G2 LM LR C LM URM C LM URA

CONDITION INDEX

Model Exp. Avg. Exp. Max. Exp. Min.

Figure 28. End connection movement: strut arm assembly.

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

100

G1 VT UR G2 VT LR

CONDITION INDEX

Model Exp. Avg. Exp. Max. Exp. Min.

Figure 29. Corrosion: strut arm assembly.
101

End Connection Movement: Figure 28

For the four strut arms for which movement was observed (Newburgh Upper

Right Miter Lock Gate, Green River #2 Lower Right Miter Lock Gate, Cannelton

Upper Right Miter Lock Gate, and Cannelton Upper Left Miter Lock Gate) the

calculated CIs closely approximated the experts’ average, with the greatest

difference being 9 points.

Compression Spring Movement

The compression spring movement distress was not calibrated because no strut

arm compression spring movement problems were observed. Hence, the calculated

CIs were all 100, and the experts’ average condition indexes were 90 or above.

Corrosion: Figure 29

The calculated CIs closely approximated the experts’ average CIs (within 5

points) for corrosion of the strut arms at the two locations (Green River #1 Right

Filling Valve and Green River #2 Right Emptying Valve) where the corrosion

distress was observed. Both of these struts were valve operating equipment. The

corrosion distress for struts was not observed on any struts used to operate miter

lock gates.

Cracks

The cracks distress was not calibrated because no cracks in strut arms were

observed. Hence, the calculated CIs were all 100 and the experts’ average CIs were

90 or above. Although this distress was not calibrated, the experts felt that cracks in

the strut were critical and should be repaired, which corresponds well to Section 4.3.

Assembly CI: Figure 30

The assembly CI for strut arms was calibrated for six assemblies. In each

case, the model CI was higher than the experts’ average CI. Although the model CIs

were higher, the experts’ average CIs and the model CIs were all in Zone 1.
102

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

100

O LS LL M LS UR M LS LR S.L. LS UR S.L. LS LR N DT 1

CONDITION INDEX

Model Exp. Avg. Exp. Max. Exp. Min.

Figure 30. Strut arm assembly CI.
103

8 Rocker Arm Assembly

8.1 Component Identification

Definitions and sketches for components of the rocker arm assembly are

presented in the following paragraphs.

Rocker

The rocker consists of steel arms that are joined with connecting pins (Figure

6). It transfers and redirects the horizontal load produced by a hydraulic cylinder to

a vertical strut arm assembly.

Pivot Point

The pivot point is the connecting pin on which the rocker rotates (Figure 6).

Connecting Rod

The connecting rod transfers force from the piston rod to the rocker (Figure 6). 

Not all rocker assemblies have connecting rods.

8.2 Inspection Form With Comments

The following page is the field inspection form for the rocker arm assembly.

The side-by-side arrangement of the opposing pages displays specific explanations

(right side) adjacent to the entry on the inspection form (left side).
104

U.S. ARMY CORPS OF ENGINEERS P.T.#: 

ROCKER ARM INSPECTION 

PROJECT NAME: 

DATE: 

VALVE IDENTIFICATION: (circle the appropriate valve)

Valve

Emptying 1. Left 2. Right

Filling 1. Left 2. Right

NOISE, JUMPING, & VIBRATION IS IT NORMAL

NOISE (Y/N) (Y/N) 

JUMPING (Y/N) (Y/N) 

VIBRATION (Y/N) (Y/N) 

PIVOT POINT ANCHORAGE MOVEMENT/DETERIORATION

MOVEMENT: (Y/N) 

CORROSION: (Y/N) 

CRACKED CONCR.: (Y/N) 

EXPOSED BOLTS: (Y/N) --------> IF YES(Y), THEN IS THERE 

CORROSION: 

MISSING OR

BROKEN NUTS: 

LOOSE NUTS: 

PIVOT POINT PIN MOVEMENT OPEN

CLOSED

(estimate movement (in.): 0, 1/8, 1/4, 3/8, 1⁄2): 

ROCKER AND CONNECTING ROD CONNECTION MOVEMENT OPEN 

CLOSED

(estimate movement(in.): 0, 1/8, 1/4, 3/8, 1⁄2): 

CORROSION

NEW SECTION THICKNESS (in.): 

SIGNIFICANT CORROSION: (Y/N)

SEVERE PITTING OR GENERAL THICKNESS REDUCTION: (Y/N) 

CRACKS

NUMBER OF CRACKS: 

LOCATION FROM POWER END(ft): 

 

COMMENTS: 

 
105

Comments: Field data

Enter the PROJECT NAME for this inspection, the DATE of the inspection, and, for the

GATE IDENTIFICATION, identify which valve is being inspected. Also enter the

power transfer number (P.T.#), which can be found on Page 1 of the inspection form.

Observation of the rocker arm during gate movement is a good indicator of problems. 

Record any indication NOISE, JUMPING, and/or VIBRATION during operation. Also

indicate whether this noise, jumping, and/or vibration is NORMAL.

Record any evidence of MOVEMENT at the ANCHORAGE of the PIVOT POINT as the

valve is opened and closed. Evidence of movement can be observed visually or enhanced

by placing a dial gage to monitor any movement (Figure 31). A dial gage change greater

than 0.002 in. is considered movement. Excessive concrete spalling may indicate a

displacement occurred at this location at some time. Also, record the presence of any

CORROSION (10% volume loss) of the steel portion or any CRACKED CONCRETE at

the interface of the embedment. Small hairline cracks, probably caused by thermal

expansion or contraction of the concrete, should be ignored. Indicate if there are any

CORRODED (10% volume loss), MISSING OR BROKEN, or LOOSE nuts at this

connection if the BOLTS are EXPOSED.

Record the relative MOVEMENT at the PIVOT POINT PIN (Figure 31) between the

rocker and the anchorage bracket by visual observation to the nearest 1/8 in. To further

enhance the visual observation, place a dial gage at this location.

Record the relative CONNECTION MOVEMENT between the ROCKER AND

CONNECTING ROD (Figure 31) by visual observation to the nearest 1/8 in. To further

enhance the visual observation, place a dial gage at this location.

The presence of excessive CORROSION on the rocker arm or connecting rod is a

potential problem. Select the section of the rocker arm or connecting arm with the most

corrosion. From construction drawings, record the NEW SECTION THICKNESS at this

location. Record YES if there is SIGNIFICANT CORROSION (more than general

scaling). If yes, indicate if there is SEVERE PITTING (1/8 in. pits or greater) in a dense

pattern or GENERAL THICKNESS REDUCTION of 10% or greater in local areas.

The presence of CRACKS on the rocker arm assembly is usually not tolerated. Record

the NUMBER OF CRACKS found by visual observation of the rocker and connecting

rod. Many times a crack will show up as corrosion under the painted surface. Also

record the LOCATION of any cracks.

Note: Wear at the connection of the rocker to the strut is recorded in the STRUT

inspection, and wear at the connection of the rocker to the piston rod is recorded in the

HYDRAULIC CYLINDER inspection.
106

P IS T O N R O D C O N N E C T IN G R O D 

 

P IV O T P O IN T P IN

C O N N E C T IN G P IN B E T W E E N 

C O N N E C T IN G R O D 

AN D RO C KER AR M

D IA L G A G E

T O VALV E

C Y L IN D E R E N D C O N N E C T IO N P IN

C O N N E C T IO N P IN T O S T R U T

S TRUT

P IV O T P O IN T 

AN C H O R AG E

Figure 31. Rocker arm distress measurements.

8.3 Condition Index

The following section contains the rules for calculating the individual CIs for

the rocker arm assembly distresses. Distress descriptions and example illustrations

are also provided.

Noise, Jumping, Vibration

See noise, jumping, vibration for the exposed gear assembly (Chapter 4, p 51).

Pivot Point Anchorage Movement/Deterioration

See anchorage movement/deterioration for the exposed gear assembly

(Chapter 4, p 51).

Pivot Point Pin Movement

See end connection movement for the strut arm assembly (Chapter 7, p 101).
107

Rocker and Connecting Rod Connection Movement

See end connection movement for the strut arm assembly (Chapter 7, p 101).

Corrosion

See corrosion for the strut arm assembly (Chapter 7, p 101).

Cracks

See cracks for the exposed gear assembly (Chapter 4, p 54).

Assembly CI

The assembly CI will be calculated with Equations 2.2, 2.5, and 2.6 (See

Chapter 2, Assembly Distress). The lone critical distress in the rocker arm

assembly is the crack distress. The CIs from the remaining five distresses will be

used to calculate the weighted CIw (Equation 2.5). The weighting factors for those

five distresses are in Table 17.

8.4 Field Tests

The bar charts in Figures 32 and 33 compare the experts' subjective condition

index from the field tests with the CI calculated from the rules in Section 8.3 for two

rocker arm distresses. Only data from assemblies with observed distresses are plotted. Comparisons between the calculated and experts' CIs are summarized below.

Noise, Jumping, Vibration

The noise, jumping, and vibration distress was not calibrated because no noise,

jumping, or vibration in rocker arms was observed. Hence, the calculated CIs were

all 100 and the experts’ average CIs were 90 or above. The noise, jumping, and

vibration distress was calibrated in the enclosed gear assembly, and the calculated

CIs closely approximated the experts’ averages.

Pivot Point Anchorage Movement/Deterioration: Figure 32

The pivot point anchorage movement/deterioration distress was observed on a

filling valve at Green River #1 Lock. The experts’ average was 15 points higher

than the calculated CI of 40.
108

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

100

G1 VT UR

CONDITION INDEX

Model Exp. Avg. Exp. Max. Exp. Min.

Figure 32. Pivot point anchorage movement/deterioration: rocker arm assembly.

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

100

G1 VT UR G2 VT UR

CONDITION INDEX

Model Exp. Avg. Exp. Max. Exp. Min.

Figure 33. Pivot point pin movement: rocker arm assembly.
109

Pivot Point Pin Movement: Figure 33

The pivot point pin movement distress was observed at two locations. At

Green River #1, the movement was 1/16 in. and the calculated CI was very close to

the experts’ average. Although the movement was four times larger at the second

location (1/4 inch at Green River #2), the experts lowered their average by only 12

points, from 72 to 60. The calculated CI at the second location decreased by 39

points and was equal to the expert low (40).

Movement Between Rocker and Connecting Rod

The movement between rocker and connecting rod distress was not calibrated

because no relative movement was observed between the rocker and the connecting

rod in rocker arms. Hence, the calculated CIs were all 100, and the experts’ average

CIs were 90 or above.

Corrosion

The corrosion distress was not calibrated because no significant corrosion was

observed in rocker arms. Hence, the calculated CIs were all 100, and the experts’

average CIs were 90 or above. The rule for the corrosion distress was, however,

calibrated for strut arms, and the calculated CIs closely approximated the experts’

averages.

Cracks

The cracks distress was not calibrated because no rocker arms cracks were

observed. Hence, the calculated CIs were all 100, and the experts’ average CIs were

90 or above. Although this distress was not calibrated, the experts felt that cracks in

the rocker arm were critical and should be repaired, which corresponds well to

Section 4.3.

Assembly CI: Figure 34

The assembly CI for rocker arms was calibrated for two assemblies. The

model CI was slightly lower than the experts’ average CI for the case in Zone 2

(Upper Right Valve Green River #1), and was higher than the experts’ average CI

for the case in Zone 1 (Lower Right Valve Green River #2).
110

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

100

G1 VT UR G2 VT LR

CONDITION INDEX

Model Exp. Avg. Exp. Max. Exp. Min.

Figure 34. Rocker arm assembly CI.
111

E L E C T R IC M O T O R

S E C T O R G AT E

LO C K C HAMBER

LO C K W ALL

C ABLE

R E D U C T IO N

G EARS

C ABLE D RU M

S H E AV E S

Figure 35. Plan view of sector lock gate operating equipment.

9 Cable Assembly

9.1 Component Identification

Definitions and sketches for components of the cable assembly are presented

in the following paragraphs. Cable lifting systems are sometimes used to raise and

lower or open and close the structures (Figures 35, 36, and 37).

Cable (wire rope)

The cable is made up of several strands (Figure 38) usually wound in one of

two ways: regular or lang lay. The wires of a regular lay are twisted to make the

strands, and the strands are then twisted in the opposite direction to make the rope. 

The wires in the regular lay end up running in the longitudinal direction. Figure 38

shows a lang lay, where the wires and strands are twisted in the same direction.
112

C A B L E D R U M , G E A R

S Y S T E M , A N D M O T O R 

C ABLE 

 

L IF T IN G 

BR AC KET

T A IN T E R G AT E

Figure 36. Side view of tainter dam gate operating equipment.

Cable Strand

The cable strand is composed of several wires wrapped together in various

arrangements (Figure 38).

Cable Wire

The smallest component of the cable is the single steel wire (Figure 38).

Cable Lay

The cable lay is the length of cable in which a strand makes one complete

revolution of the cable (Figure 38).

Cable Drum

The cable drum is the component around which the cable is wound as the

valve structure is raised and lowered or the gate is moved (Figures 35 and 39).
113

V e rtic a l L ift G a te

P is to n H y d ra u lic C y lin d e r S heaves

C a b le

E le v a tio n V ie w

S heaves

P is to n

H y d ra u lic C y lin d e r

C a b le

P la n V ie w

Figure 37. Vertical lift gate operating equipment.

R O P E L AY

C ABLE S T RAN D 3

 (s h a d e d ) C A B L E W IR E

C ABLE S T RAND 1

C ABLE S T RAN D 2

Figure 38. Cable schematic.
114

MOTO R

S H A F T M O U N T IN G B R A C K E T

P IN IO N

G EAR

C ABLE D RUM

G EAR BO X

S HAFT

C OVER 

P L AT E

AN C HO R AG E

C O U P L IN G

Figure 39. Plan view of tainter gate operating equipment.

Sheave

The sheave is a wheel with a grooved rim. It is used to redirect the cable

(Figures 35 and 37).

Idler/Roller

The idler, or roller, is a pulley used to guide and take up slack in the cable.

9.2 Inspection Form With Comments

The following pages are Parts 1, 2, and 3 of the field inspection forms for a

cable assembly. The side-by-side arrangement of the opposing pages displays

specific explanations (right side) adjacent to the entry on the inspection form (left

side).
115

Intentionally Blank
116

U.S. ARMY CORPS OF ENGINEERS P.T.#: 

CABLE INSPECTION PART 1

PROJECT NAME: 

DATE: 

GATE IDENTIFICATION: (identify the appropriate structure)

Lock Gate

Upper 1. Left Leaf 2. Right Leaf

Lower 1. Left Leaf 2. Right Leaf

Valve

Emptying 1. Left 2. Right

Filling 1. Left 2. Right

Dam Gate

Number CABLE #

 FROM

LEFT

NUMBER OF CABLES IN THE CABLE SET: ______ FACING 

 

DOWNSTREAM 

NOISE, JUMPING, AND VIBRATION IS IT 

NORMAL 

 NOISE (Y/N) (Y/N) 

JUMPING (Y/N) (Y/N) 

VIBRATION (Y/N) (Y/N) 

OUTER WIRE WEAR 

WORN PORTION? (Y/N) 

PERCENTAGE OF WEAR: 

LOCATION (from power end (ft)): 

REDUCTION IN ROPE DIAMETER 

DIAMETER REDUCTION? (Y/N) 

NEW DIAMETER (in.): 

REDUCED DIAMETER (in.): 

LOCATION (from power end (ft)): 

CORROSION 

CORROSION? (Y/N) 

 IF YES, (1) SLIGHT(colored) OR (2) SEVERE (pitted): 

 LOCATION (from power end (ft)): 

IS THE CABLE LUBRICATED PROPERLY: 

IS THE CABLE CARBON STEEL(C),

GALVANIZED(G), OR STAINLESS(S): 

YEARS SINCE LAST REPLACED: 

COMMENTS: 

 

 
* Figures 40 through 43 are placed at the end of this section (beginning on p 124).

117

Part 1 Comments: Field data

Enter the PROJECT NAME for this inspection, the DATE of the inspection, and, for the

GATE IDENTIFICATION, identify which gate or valve is being inspected. Also enter

the power transfer number (P.T.#), which can be found on Page 1 of the inspection form.

Indicate the NUMBER OF CABLES IN THE CABLE SET.

Observation of the cable assembly during gate and valve movement is a good indicator of

problems. Record any indication of NOISE, JUMPING, and/or VIBRATION during the

operation of the structure. Also indicate whether this noise, jumping, and/or vibration is

NORMAL. 

Record if a WORN PORTION of the outer cable WIRES is evident. If wear is evident,

record the average PERCENTAGE of WEAR of the wire diameter on the outer wires. 

The wear would most likely occur near the drum when the gate is in the opened or closed

position. Also indicate the LOCATION of the worn section from the power end (Figure

40*

). 

Record if a REDUCTION IN ROPE DIAMETER of the cable is evident. If there is

evidence of a reduced diameter, record the NEW DIAMETER and the smallest

REDUCED DIAMETER. Look closely at the cable that is near the drum when the gate is

in the opened or closed position. The reduction in area of the cable would most likely

occur at the point of smallest radius of cable bend. The reduced diameter of the cable can

often be checked with cable templates or with the use of calipers. Indicate the

LOCATION of the reduced area from the power end (Figure 40).

In steel cables, CORROSION of interior wires in the cable regularly occurs but is

difficult to identify. Record any evidence of corrosion such as local discoloring or pitting

of the wires. The splash zone is often a problem spot. Indicate whether the corrosion is

SLIGHT (slight discoloration) or SEVERE (pitting and/or severe rusting). Indicate the

LOCATION from the power end where the corrosion occurs (Figure 40). Record

whether the CABLE is LUBRICATED PROPERLY. Indicate the type of cable

(CARBON STEEL, GALVANIZED, or STAINLESS). Also record the number of

YEARS SINCE the cable has LAST been REPLACED.
118

U.S. ARMY CORPS OF ENGINEERS P.T.#: 

CABLE INSPECTION PART 2

BIRD CAGES, KINKS, AND PROTRUDING CORE 

BIRD CAGES(B), KINKS(K), OR 

PROTRUDING CORE(P): (Y/N) 

IF YES WHICH ONE(S)? 

LOCATION (from power end (ft)): 

UNLAYED STRANDS 

UNLAYED STRANDS: (Y/N) 

LOCATION (from power end (ft)): 

WIRE BREAKAGE 

NUMBER OF BROKEN WIRES IN ONE ROPE LAY: 

LOCATION (from power end (ft)): 

UNEQUAL TENSION 

UNEQUAL CABLE TENSION: (Y/N) 

NUMBER OF UNTENSIONED CABLES: 

DRUM WEAR

VISIBLE GROOVE WEAR: (Y/N) 

 IF YES, ESTIMATE DEPTH OF WORN GROOVE IN % OF CABLE DIAMETER? 

IF GREATER THAN 10%, MEASURED DEPTH OF WORN GROOVE (%): 

SIDE WEAR: (Y/N) 

DRUM ANCHORAGE MOVEMENT/DETERIORATION

MOVEMENT: (Y/N) 

CORROSION: (Y/N) 

CRACKED CONCR.: (Y/N) 

EXPOSED BOLTS: (Y/N) 

IF YES (Y), THEN IS THERE --------> CORROSION: (Y/N) 

 MISSING OR 

BROKEN NUTS: (Y/N) 

LOOSE NUTS: (Y/N) 

 

ARE THERE ANY SHEAVES IN THE CABLE ASSEMBLY(Y/N)? 

IF YES, COMPLETE THE FOLLOWING QUESTIONS ON SHEAVES

SHEAVE NUMBER: 1 2 3 4

SHEAVE WEAR

VISIBLE GROOVE WEAR(Y/N): 

IF YES, ESTIMATE DEPTH OF WORN 

GROOVE IN % OF CABLE DIAMETER? 

IF GREATER THAN 10%, 

MEASURED DEPTH OF WORN GROOVE (%): 

SIDE WEAR (Y/N): 

SHEAVE BEARING/BUSHING WEAR

DOES THE SHEAVE WOBBLE (Y/N): 

LATERAL DISPLACEMENT OF SHEAVE 

WHEN PRYING: 

RADIUS OF SHEAVE(ft): 
119

Part 2 Comments: Field data

A BIRD CAGE is a local area of unraveled portion of the cable (Figure 41). Record the

existence of BIRD CAGES, KINKS, OR PROTRUDING CORES (Figure 42) on the

inspection form. Indicate the type of distress (a bird cage, a kink, or a protruding core) if

one of the three exists. Also record the LOCATION from the power end that this

distress occurs (Figure 40).

Record any existence of UNLAYED cable STRANDS. Unlayed strands occur when the

cable rubs against an object. Unlayed strands are the strands displaced from the

uniformly distributed manufactured position. Also indicate the LOCATION of the

unlayed strands from the power end (Figure 40).

Record the maximum number of BROKEN WIRES in all strands of any ONE ROPE

LAY (Figure 38). Also indicate the LOCATION of the broken wires from the power end

of the cable (Figure 40).

For cable sets with more than one cable, observe the cable and indicate if UNEQUAL

TENSION occurs in each CABLE. Cable tension can be tested by applying equal force

perpendicular to the length of each cable and observing the displacement of the cable in

the direction of the force. The displacements should be equal if the cable tension is equal. 

Cable tension can also be tested by observing the vibration in each cable as wind or other

disturbance vibrates the cable. If the cable tension for a cable is unequal, the vibrations in

the cables could occur at different frequencies. The tension can also be tested by striking

each cable separately and listening to the frequency of each cable. Cables with equal

tension will have the same frequency. Also record the NUMBER of CABLES that have

no or little tension.

For DRUMS, record if there is VISIBLE GROOVE WEAR. Groove wear is the wearing

of the bottom of the grooves. If there is groove wear, estimate the DEPTH OF the

GROOVE WEAR in percentage of the CABLE DIAMETER. If the estimate of groove

wear is GREATER THAN 10% of the cable diameter, use an appropriate method to

MEASURE the groove wear. Groove wear can be measured by placing a cable groove

template into the groove and observing the gap between the bottom of the groove and the

template. A similar procedure that can be used is to place a piece of new cable into the

groove and to measure the gap. Indicate whether there is SIDE WEAR on the drum. If

the cable is misaligned, the guide plates will show the imprint of the cable (Figure 43). 

Record any evidence of MOVEMENT at the DRUM ANCHORAGE as the gate or valve

is opened and closed. Evidence of movement can be observed visually or enhanced by

placing a dial gage to monitor any movement. A dial gage change greater than 0.002 in.

is considered movement. Excessive concrete spalling may indicate a displacement

occurred at this location at some time. Also, record the presence of any CORROSION

(10% volume loss) of the steel portion or any CRACKED CONCRETE at the interface of

the embedment. Small hairline cracks, probably caused by thermal expansion or

contraction of the concrete, should be ignored. Indicate if there are any CORRODED

(10% volume loss), MISSING OR BROKEN, or LOOSE nuts at this connection if the

BOLTS are EXPOSED.
120

U.S. ARMY CORPS OF ENGINEERS P.T.#: 

CABLE INSPECTION PART 2

BIRD CAGES, KINKS, AND PROTRUDING CORE 

BIRD CAGES(B), KINKS(K), OR 

PROTRUDING CORE(P): (Y/N) 

IF YES WHICH ONE(S)? 

LOCATION (from power end (ft)): 

UNLAYED STRANDS 

UNLAYED STRANDS: (Y/N) 

LOCATION (from power end (ft)): 

WIRE BREAKAGE 

NUMBER OF BROKEN WIRES IN ONE ROPE LAY: 

LOCATION (from power end (ft)): 

UNEQUAL TENSION 

UNEQUAL CABLE TENSION: (Y/N) 

NUMBER OF UNTENSIONED CABLES: 

DRUM WEAR

VISIBLE GROOVE WEAR: (Y/N) 

 IF YES, ESTIMATE DEPTH OF WORN GROOVE IN % OF CABLE DIAMETER? 

IF GREATER THAN 10%, MEASURED DEPTH OF WORN GROOVE (%): 

SIDE WEAR: (Y/N) 

DRUM ANCHORAGE MOVEMENT/DETERIORATION

MOVEMENT: (Y/N) 

CORROSION: (Y/N) 

CRACKED CONCR.: (Y/N) 

EXPOSED BOLTS: (Y/N) 

IF YES (Y), THEN IS THERE --------> CORROSION: (Y/N) 

 MISSING OR 

BROKEN NUTS: (Y/N) 

LOOSE NUTS: (Y/N) 

 

ARE THERE ANY SHEAVES IN THE CABLE ASSEMBLY(Y/N)? 

IF YES, COMPLETE THE FOLLOWING QUESTIONS ON SHEAVES

SHEAVE NUMBER: 1 2 3 4

SHEAVE WEAR

VISIBLE GROOVE WEAR(Y/N): 

IF YES, ESTIMATE DEPTH OF WORN 

GROOVE IN % OF CABLE DIAMETER? 

IF GREATER THAN 10%, 

MEASURED DEPTH OF WORN GROOVE (%): 

SIDE WEAR (Y/N): 

SHEAVE BEARING/BUSHING WEAR

DOES THE SHEAVE WOBBLE (Y/N): 

LATERAL DISPLACEMENT OF SHEAVE 

WHEN PRYING: 

SHEAVE RADIUS(ft): 

Part 2 Comments: Field data (continued)
121

The FOLLOWING QUESTIONS ON SHEAVES should be answered only if there ARE

SHEAVES IN THE CABLE ASSEMBLY.

Record if there is VISIBLE GROOVE WEAR. Groove wear is the wearing of the bottom

of the grooves. If there is groove wear, estimate the DEPTH OF the WORN GROOVE in

percentage of the CABLE DIAMETER. If the estimate of groove wear is GREATER

THAN 10% of the cable diameter, use an appropriate method to MEASURE the groove

wear. Groove wear can be measured by placing a cable groove template into the groove

and observing the gap between the bottom of the groove and the template. A similar

procedure that can be used is to place a new cable into the groove and to measure the gap. 

Also indicate whether there is SIDE WEAR on the sheave. 

Record if there is SHEAVE BEARING/BUSHING WEAR. Bearing and bushing wear

can be observed by placing a pry bar between the sheave and a solid surface or watching

the sheave during operation and checking for WOBBLE. Also record the LATERAL

DISPLACEMENT observed when PRYING the SHEAVE. 
122

U.S. ARMY CORPS OF ENGINEERS P.T.#: 

CABLE INSPECTION PART 3

SHEAVE ANCHORAGE MOVEMENT/DETERIORATION

SHEAVE NUMBER: 1 2 3 4

MOVEMENT(Y/N): 

CORROSION(Y/N): 

CRACKED CONCR.(Y/N): 

EXPOSED BOLTS(Y/N): 

IF YES(Y), THEN IS THERE

CORROSION(Y/N): 

MISSING OR

BROKEN NUTS(Y/N): 

LOOSE NUTS(Y/N): 

IDLERS/ROLLERS WEAR

ARE THERE ANY IDLERS OR ROLLERS IN THE CABLE ASSEMBLY(Y/N)? 

IF YES, THEN ANSWER THE FOLLOWING QUESTIONS FOR IDLERS AND ROLLERS

IDLER/ROLLER NUMBER: 1 2 3 4

ARE IDLERS/ROLLERS

WORKING PROPERLY(Y/N): 

IF NO, IS THE CABLE 

BEING DAMAGED(Y/N): 

GATE OR VALVE CONNECTION MOVEMENT 

IS THE GATE OR VALVE CONNECTION OBSERVABLE(Y/N)? 

IF YES, ESTIMATE THE MOVEMENT(in.):(0, 1/8, 1/4, 3/8, 1⁄2): 

COMMENTS: 

 
123

Part 3 Comments: Field data

Record any evidence of MOVEMENT greater than 0.002 in. at the SHEAVE

ANCHORAGE as the gate is opened and closed. Evidence of movement can be observed

visually or enhanced by placing a dial gage to monitor any movement. Excessive

concrete spalling may indicate a displacement occurred at this location at some time. 

Also, record the presence of any CORROSION (10% volume loss) of the steel portion or

any CRACKED CONCRETE at the interface of the embedment. Small hairline cracks,

probably caused by thermal expansion or contraction of the concrete, should be ignored.

Indicate if there are any CORRODED (10% volume loss), MISSING OR BROKEN, or

LOOSE nuts at this connection if the BOLTS are EXPOSED. 

Record whether there ARE ANY IDLERS OR ROLLERS IN THE CABLE ASSEMBLY

being inspected. IF YES, record whether the IDLERS and/or ROLLERS are WORKING

PROPERLY. Idlers and rollers should rotate freely and should not wobble as the cable

passes through them. If the idlers or rollers are not functioning properly, record if the

CABLE is being DAMAGED by the malfunction of the idlers or rollers.

Record whether the GATE OR VALVE CONNECTION IS OBSERVABLE. IF YES,

record the evidence of GATE OR VALVE CONNECTION MOVEMENT by estimating

the relative movement to the nearest 1/8 in. between the gate or valve and the end of the

cable (Figure 27).
124

C H A IN O R C A B L E 

L O C A T I O N (ft. ) T O T H E

C H A IN O R C A B L E D IS T R E S S

FRO M T HE PO W ER END

I f th e w o rs t s e c tio n o f

c a b le o r c h a in is lo c a te d

c o u n te r-c lo c k w is e fro m 

p o in t A , th e v a lu e w ill

b e n e g a tiv e .

T h e g a te o r v a lv e 

s h o u ld b e in th e c lo s e d 

p o s itio n to ta ke th e 

m e a s u re m e n t.

A

Figure 40. Location identification for cable and chain distresses.

Figure 41. Cable bird cage.
125

Figure 42. Cable protruded core.

C ABLE

T O G AT E

AX LE

S ID E W E A R A R E A

A BLE D RUM

T O G AT E

AX LE

S ID E W E A R A R E A

C ABLE S P O O L

C ABLE

Figure 43. Cable drum wear.

9.3 Condition Index

The following section contains the rules for calculating the individual CIs for

the cable assembly distresses. Distress descriptions and example illustrations are

also provided.

Noise, Jumping, and Vibration

See noise, jumping, and vibration for the exposed gear assembly (Chapter 4, p

51).

Outer Wire Wear

Definitions and causes. Wire wear is the reduction in diameter of the cable

wires. Wear occurs when the cable moves over drums or through abrasive mediums.
126

 (9.1)

 

  (9.2)



Measurements and limits. The percentage of wear on the outer wires, X, is

recorded. The limiting value for this distress is:

(U.S. Army Corps of Engineers, 1987).

Example: The outer wires of a cable were worn an average of 20%. The CI for the

cable wear distress is:

The CI is rated Marginal.

Reduction in Rope Diameter

Definition and causes. A reduction in the cable diameter may be attributed to

excessive external abrasion, internal or external corrosion, loosening or tightening of

rope lay, inner wire breakage, and/or rope stretch.

Measurement and limits. The new diameter of the cable, XNEW , and the

diameter at the minimum cross section, XWORN , are recorded on the inspection form. 

The difference between these diameters is:

The values for XMAX are:

Original Diameter of Cable XMAX

up to 3/4 in. 3/64 in.

7/8 in. to 1-1/8 in. 1/16 in.

1-1/4 in. and up 3/32 in.

(U.S. Army Corps of Engineers, 1987).

Example: The inspection of a cable assembly revealed significant reduction in

diameter of the cable. The new and current diameters were:
127



  

 



Equation 9.2 gives the difference between these diameters:

With the original diameter between 7/8 in. and 1-1/8 in., XMAX is 1/16 in. The CI is

calculated with Equation 2.1:

This CI is rated Fair.

Corrosion

Definition and causes. Corrosion of cables can cause sudden failure with

little warning, and as cables often corrode from the inside out, it is important to

determine if any internal corrosion is occurring. Corrosion of cables is caused by

interaction with the environment and a lack of lubrication.

Measurement and limits. If slight corrosion is evident (e.g., slight

discoloring), the CI will be 70. However, if the cable has pitting or severe rusting,

the CI will be 40 (Committee of Wire Rope Producers, 1979).

Example: While inspecting the cable near the splash zone in a cable assembly,

severe rusting was detected. The CI for corrosion is:

The CI is rated Marginal.

Bird Cages, Kinks, and Protruding Core

Definition and causes. A bird cage is a local area of severely unraveled cable

(Figure 41). Bird cages form when slack develops in the cable and that slack is

suddenly removed. Bird cages can also be formed when the cable is wrapped too

tightly around drums. Kinks are permanent distortions caused by loops being drawn

too tightly. A protruding core occurs when the center strand protrudes through the

outer strands (Figure 42).
128





 (9.3)

Measurement and limits. The existence of bird cages, kinks, and protruding

cores is recorded in the inspection form. If one or any combination of these three

distresses occurs, the CI will be 40 (U.S. Army Corps of Engineers, 1987).

Example: A kink was found in a cable assembly during an inspection. The CI

for this distress is:

The CI is rated Marginal.

Unlayed Strands

Definition and causes. A cable is comprised of several uniformly distributed

individual strands. Sometimes the strands become displaced along one side of the

rope. These displacements can be caused by rubbing around or against an object.

Measurement and limits. The existence of any unlayed strands are recorded

in the inspection form. If unlayed strands exist the CI will be 40.

Example: Several unlayed strands were found during a cable assembly inspection.

The CI for the unlayed strands is:

The rating for this CI is Marginal.

Wire Breakage

Definition and causes. This distress deals with the number of broken wires in

a length of cable known as a rope lay. Broken wires can be caused by excessive

loads, fatigue, and wear.

Measurement and limits. The maximum number of broken wires, X, in all of

the strands within any one rope lay are recorded for each cable set. The limiting

value of broken wires per rope lay is:

(U.S. Army Corps of Engineers, 1987).
129

 

 (9.4)

 

Example: Four broken wires were found in one rope lay of a cable. The CI for

broken wires is:

The CI is rated Marginal.

Unequal Tension

Definition and causes. For a cable operated structure to be operating

properly, the cables should have equal tension. For multiple cables, it is important

that all the cables be tensioned uniformly. Some cables may be overstressed if the

load is not evenly distributed.

Measurement and limits. The number of cables that are relatively

untensioned, X, is recorded in the inspection form. The limiting value for

untensioned cables is:

Example: One cable had a different frequency when struck than the other cables in

the set, signaling unequal tension. The CI for unequal tension is:

This CI is rated Marginal.

Drum Wear

Definition and causes. Drum wear is the reduction of steel in the cable drum

through wearing. The cause for this wearing is the misalignment of the cable and

drum during operation and wear due to normal use.

Measurement and limits. The existence of drum wear or damage is recorded

in the inspection form. If drum wear exists, an estimate of the groove wear is

recorded. The groove wear is given in percentage of the cable diameter. If the

estimated groove wear is less than 10 percent the CI is 70. If the estimated groove
130

 (9.5)

 

wear is equal to or greater than 10 percent, the wear is measured. The limiting value

for groove wear is:

If side wear is evident, the CI must be less than or equal to 70 (Department of the

Army Hydroelectric Design Center, North Pacific Division, Army Corps of

Engineers, 1993).

Example: Drum wear was evident on a cable assembly. The estimated percentage

of groove wear was 20 percent. The wear was then measured with a template and

was found to be 15 percent. The CI for drum wear is:

This CI is rated Fair.

Cable Drum Anchorage Movement/Deterioration

See anchorage movement/deterioration for the exposed gear assembly

(Chapter 4, p 51).

Sheave Wear

See drum wear for the cable assembly (Chapter 9, p 130).

Sheave Bearing/Bushing Wear

See bearing/bushing wear for the exposed gear assembly (Chapter 4, p 52).

Sheave Anchorage Movement/Deterioration

See anchorage movement/deterioration for the exposed gear assembly

(Chapter 4, p 51).

Idlers/Rollers Wear

Definitions and causes. The distress for idlers and rollers is the wear or

wobbling of the idlers or rollers. As a groove is worn in the idler or roller, the rate

of wear in the cable increases. Wobbling of the idler or roller can cause the cable to
131



untrack. Wear and wobbling can be caused by normal use and improper lubrication. 

Wobbling can also be caused by wear between the idler or roller and the shaft on

which it rotates.

Measurements and limits. If the idlers or rollers do not work properly, but

are not causing damage to the cable, the CI is 70. If damage is occurring to the cable

because the idlers or rollers are not working properly, the CI is 40.

Example: A deep groove was cut in an idler, causing extensive damage to the cable.

The CI for idlers/rollers is:

The CI is rated Marginal.

Gate or Valve Connection Movement

See end connection movement for the strut arm assembly (Chapter 7, p 97).

Assembly CI

The assembly CI will be calculated with Equations 2.2, 2.5, and 2.6 (See

Chapter 2, Assembly Distress). The two critical distresses in the cable assembly are

the bird cage, kink, or protruding core distress and the wire breakage distress. The

CIs from the remaining 13 distresses will be used to calculate the weighted CI w

(Equation 2.5). The weighting factors for those 13 distresses are in Table 18.

9.4 Field Test

The bar charts in Figures 44 and 45 compare the experts’ subjective CI from

the various field tests to the CI calculated from the rules in Section 9.3 for two cable

distresses. Only data from assemblies with observed distresses were plotted. Comparisons between the calculated and experts’ average CIs are summarized below.

Noise, Jumping, and Vibration

The noise, jumping, and vibration distress was not calibrated because noise,

jumping, or vibration was not observed in cables. Hence, the calculated CIs were all

100, and the experts’ average CIs were 90 or above. The noise, jumping, and
132

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

100

WP LS UR WP LS LR M LS UR M LS LR

CONDITION INDEX

Model Exp. Avg. Exp. Max. Exp. Min.

Figure 44. Outer wire wear: cable assembly.

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

100

 G1 LM UR G2 LM UR G2 LM LR C LM URM C LM URA

CONDITION INDEX

Model Exp. Avg. Exp. Max. Exp. Min.

Figure 45. Wire breakage: cable assembly.

vibration distress was calibrated in the enclosed gear assembly, and those calculated

CIs closely approximated the experts’ averages.

Outer Wire Wear: Figure 44

The outer wire wear distress was observed in four of the 22 assemblies that

were inspected during the field tests. For the remaining 18 assemblies, the calculated CIs were 100, and the experts’ average CIs were 90 or above. In the four

assemblies for which wire wear was observed (Upper Right Sector Lock Gate W.P.
133

Franklin, Lower Right Sector Lock Gate W.P. Franklin, Upper Right Sector Lock

Gate Moorehaven, and Lower Right Sector Lock Gate Moorehaven), the assemblies

were used to operate sector lock gates. In all four cases, the experts’ average CI was

higher than the calculated CI; however, in three of those cases, the experts’ average

CI was within 10 points of the calculated CI. Because the value of XMAX was taken

from the Safety and Health Requirements Manual (USACE 1987), it will not be

adjusted.

Reduction in Rope Diameter

The reduction in rope diameter was observed in three cable assemblies during

the field tests. The measurement technique used to determine the amount of

reduction, however, was inaccurate. A new technique is now described in Section

9.2. While this distress cannot be calibrated, the value of X MAX was taken from the

Safety and Health Requirements Manual (USACE 1987).

Corrosion

The corrosion distress was not calibrated because corrosion was not observed

in cables. Hence, the calculated CIs were all 100, and the experts’ average CIs were

90 or above. While this distress cannot be calibrated, the rule for the corrosion of

the cable assembly was based on the Safety and Health Requirements Manual

(USACE 1987).

Bird Cages, Kinks, and Protruding Core

The bird cages, kinks, and protruding core distress was not calibrated because

the cable assemblies observed did not show this type of damage. Hence, the calculated CIs were all 100, and the experts’ average CIs were 90 or above. Although this

distress was not calibrated, the experts agree with the Wire Rope Users Manual

(Committee of Wire Rope Producers 1979), which states that wire rope should be

replaced immediately if any one of these three types of damage exists in the cable. 

This corresponds well to the rule in Section 9.3 for this distress.

Unlayed Strands

The unlayed strands distress was not calibrated because no unlayed strands

were observed in cables during the field tests. Hence, the calculated CIs were all

100, and the experts’ average CIs were 90 or above.
134

Wire Breakage: Figure 45

Broken wires were observed in five of the 22 cables assemblies inspected

during the field trips. The calculated CIs were 100, and the experts’ average CIs

were 90 or above for all 22 assemblies for which wire breakage was not observed. 

For the five cable assemblies for which broken wires were observed, the calculated

CIs were higher than the experts’ average CIs for two cases and were lower on the

remaining three cases. The rule in Section 9.3 for wire breakage was based on the

Wire Rope Users Manual (Committee of Wire Rope Producers 1979).

Unequal Tension

The equal tension distress was not calibrated because unequal tension was not

observed in cables during the field tests. Hence, the calculated CIs were all 100, and

the experts’ average CIs were 90 or above.

Drum Wear

The drum wear distress was not calibrated because drum wear in the cable

drums was not observed during the field tests. Hence, the calculated CIs were all

100 and the experts’ average CIs were 90 or above. Although the drum wear

distress was not calibrated, the current rule is based on discussion with the experts.

Drum Anchorage Movement/Deterioration

The drum anchorage movement/deterioration distress was not calibrated

because no movement or deterioration was detected in any of the drum anchorages. 

Hence, the calculated CIs were all 100 and the experts’ average CIs were 90 or

above. The anchorage movement/deterioration distress was calibrated for the

exposed gear assemblies (Section 4.4).

Sheave Wear

The sheave wear distress was observed on two cable assemblies at the W.P.

Franklin Lock. The sheave wear distress was not on the inspection form when the

distress was observed and, therefore, cannot be calibrated. Although the sheave

wear distress was not calibrated, the current rule is based on discussion with the

experts.
135

Sheave Bearing/Bushing Wear

The sheave bearing/bushing wear distress was not calibrated because no wear

in the sheaves was observed during the field tests. Hence, the calculated CIs were

all 100, and the experts’ average CIs were 90 or above. The bearing/bushing wear

distress was calibrated for the exposed gear assemblies (Section 4.4).

Sheave Anchorage Movement/Deterioration

The sheave anchorage movement/deterioration distress was not calibrated

because no movement or deterioration was detected in any of the sheave anchorages. 

Hence, the calculated CIs were all 100, and the experts’ average CIs were 90 or

above. The anchorage movement/deterioration distress was calibrated for the

exposed gear assemblies (Section 4.4).

Idler/Roller Wear

The idler/roller wear distress was observed on two cable assemblies at the

W.P. Franklin Lock. The idler/roller distress was added to the inspection form after

the first field test but was not observed in succeeding field tests. Therefore, the

distress cannot be calibrated. Although the idlers/rollers distress was not calibrated,

the current rule is based on discussion with the experts.

Gate or Valve Connection Movement

The gate or valve connection distress was not calibrated because no relative

movement was detected at the gate or valve connections. Hence, the calculated CIs

were all 100 and the experts’ average CIs were 90 or above.

Assembly CI: Figure 46

The assembly CI for the cable assembly was calibrated for four assemblies. 

For two of the assemblies, the model CIs were significantly lower than the experts’

average CIs, and for the other two calibrated assemblies, the model CIs closely

approximated the experts’ average CIs. In only one case (Upper Right Sector Lock

Gate Moorehaven) did the model CI and the experts’ average CI fall into a different

zone. In all four cases, wire breakage (a critical distress) controlled the assembly CI.
136

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

100

WP LS UR WP LS LR M LS UR M LS LR

CONDITION INDEX

Model Exp. Avg. Exp. Max. Exp. Min.

Figure 46. Cable assembly CI.
137

RO LLER 

G AT E

G EAR

C H A IN

R A C K (In s p e c te d 

in th e R o lle r 

G a te In s p e c tio n )

S P RO C KET

Figure 47. Side view of roller dam gate operating equipment.

10 Chain Assembly

10.1 Component Identification

Definitions and sketches for components of the chain assembly are presented

in the following paragraphs.

Chain

A chain is a series of links connected to one another. Chain lifting systems are

sometimes used to raise or lower dam or lock structures (Figure 47). The chain gets

lifted and wound over a sprocket type device during the operation of the assembly.
138

R O L L E R L IN K 

R O U N D L IN K

P IN S ID E P L AT E

B U S H IN G

Figure 48. Chain link schematic.

Roller Chain

A roller chain consists of roller bushings, side plates, and pins (Figure 48). 

The roller bushings turn on the pins, thereby reducing the friction between the chain

and the sprocket. The rollers fit between the sprocket teeth.

Round Chain

The links of this chain are oval shaped and permanently fitted into one another

(Figure 48).

Sprocket

The sprocket is the component that retrieves the chain as it rotates. The chain

links fit on the sprocket teeth.
139

10.2 Inspection Form With Comments

The following pages are Parts 1 and 2 of the field inspection forms for the

chain assembly. The side-by-side arrangement of the opposing pages displays

specific explanations (right side) adjacent to the entry on the inspection form (left

side).
140

U.S. ARMY CORPS OF ENGINEERS P.T.#: 

CHAIN INSPECTION PART 1

PROJECT NAME: 

DATE: 

GATE IDENTIFICATION: (identify the appropriate structure)

Lock Gate

Upper 1. Left Leaf 2. Right Leaf

Lower 1. Left Leaf 2. Right Leaf

Valve

Emptying 1. Left 2. Right

Filling 1. Left 2. Right

Dam Gate

Number 

CHAIN LINK TYPE (circle the appropriate number): 

1) ROLLER

2) ROUND 

NOISE, JUMPING, AND VIBRATION IS IT NORMAL 

NOISE (Y/N) (Y/N) 

JUMPING (Y/N) (Y/N) 

VIBRATION (Y/N) (Y/N) 

LINKAGE WEAR/ELONGATION

LENGTH OF WORN/ELONGATED LINKS(in.): 

LENGTH OF NEW LINKS(in.): 

CRACKS

NUMBER OF CRACKS: 

LOCATION FROM POWER END (ft): 

FROZEN LINKS

FROZEN CHAIN LINKS (Y/N) 

IS THE OPERATION LIMITED? (Y/N) 

LOCATION FROM POWER END (ft): 

CORROSION/PITTING

SIGNIFICANT CORROSION: (Y/N)

SEVERE PITTING OR GENERAL THICKNESS REDUCTION: (Y/N) 

LOCATION FROM POWER END (ft): 

COMMENTS: 

 
141

Part 1 Comments: Field data

Enter the PROJECT NAME for this inspection, the DATE of the inspection, and, for the 

GATE IDENTIFICATION, identify which valve or dam gate is being inspected. Also

enter the power transfer number (P.T.#), which can be found on Page 1 of the inspection

form.

Identify whether the chain is a ROLLER or ROUND LINK TYPE.

Observation of the chain assembly during gate or valve movement is a good indicator of

problems. Record any indication of NOISE, JUMPING, and/or VIBRATION during

operation and then indicate whether this noise, jumping, and/or vibration is NORMAL.

LINKAGE WEAR/ELONGATION of the chain occurs between the links of the chain

(Figure 49). Record the LENGTH OF WORN/ELONGATED LINKS. This distance can

be measured on a roller link chain by placing a tape measure along the loaded chain and

measuring from the center to center of several consecutive link pins (Figure 49). For a

round link, measure from end to end of the links while the chain is loaded (Figure 49). 

To get a more accurate estimate of total wear and elongation, measure 10 to 20

consecutive links and divide the measured distance by the number of links. The worst

worn or elongated links will most likely be those that ride on the sprocket most

frequently, if the gate operates at a relatively constant elevation. Also record the

LENGTH OF NEW LINKS. This distance can be obtained from construction drawings. 

If construction drawings are not available, measure the distance between links that get

little use, and use this distance as an estimate of the distance between new links. 

Record the NUMBER OF CRACKS in the chain links. Also record the LOCATION of

the cracked links from the power end (Figure 40).

Many times after a structure has been in the same position for some time, the links will

lock together and not bend around the sprocket. Record a yes (Y) if the chain will not

bend around the sprocket or, in other words, the chain LINKS are FROZEN. If links are

frozen, they will often remain bent in the shape of the sprocket after they have been

loaded. If there are frozen links, record whether they cause LIMITED OPERATION of

the structure. The structure may have to be raised higher than normal to check the

probable problem links. Also record the LOCATION of the frozen links from the power

end (Figure 40).

The presence of excessive CORROSION on the chain is a potential problem. Record

YES if there is SIGNIFICANT CORROSION (more than general scaling). If yes,

indicate if there is SEVERE PITTING (1/8 in. pits or greater) in a dense pattern or

GENERAL THICKNESS REDUCTION of 10% or greater in local areas. Also record

the LOCATION of the corrosion from the power end (Figure 40).
142

U.S. ARMY CORPS OF ENGINEERS P.T.#: 

CHAIN INSPECTION PART 2

SPROCKET WEAR

WEAR? (Y/N) 

IF YES, ESTIMATE % REDUCTION OF SPROCKET TOOTH: 

IF GREATER THAN 10%, MEASURED % REDUCTION OF SPROCKET TOOTH: 

SPROCKET ANCHORAGE

MOVEMENT: (Y/N) 

CORROSION: (Y/N) 

CRACKED CONCR.: (Y/N) 

EXPOSED BOLTS: (Y/N) 

IF YES (Y), THEN IS THERE -------> CORROSION: (Y/N) 

 MISSING OR 

BROKEN NUTS: (Y/N) 

 LOOSE NUTS: (Y/N) 

END CONNECTION MOVEMENT 

IS THE GATE OR VALVE OBSERVABLE(Y/N)? 

IF YES, ESTIMATE MOVEMENT (in.):( 0, 1/8, 1/4, 3/8, 1⁄2): 

COMMENTS: 

 
143

R O L L E R L IN K 

L O O P L IN K

N E W D IA M E T E R

M E A S U R E D D IS T A N C E

N E W D IA M E T E R

M E A S U R E D D IS T A N C E

Figure 49. Chain linkage wear.

Part 2 Comments: Field data

SPROCKET WEAR is wear due to the chain constantly rubbing over the sprocket teeth. 

Record if there is WEAR of the sprocket teeth. IF YES, ESTIMATE the % of REDUCTION OF the SPROCKET TOOTH. If the estimated reduction is GREATER THAN

10%, MEASURE the % of REDUCTION OF the SPROCKET TOOTH. One way to

measure the % of reduction is to measure the width of a sprocket tooth that sees little

contact, assume that width as the new sprocket tooth width, and compare that width to the

measured width of a worn tooth. The new tooth width can also be obtained from

construction drawings. 

Record any evidence of MOVEMENT greater than 0.002 in. at the SPROCKET

ANCHORAGE as the gate is opened and closed. Evidence of movement can be observed

visually or enhanced by placing a dial gage to monitor any movement. Excessive

concrete spalling may indicate a displacement occurred at this location at some time. 

Also, record the presence of any CORROSION (10% volume loss) of the steel portion or

any CRACKED CONCRETE at the interface of the embedment. Small hairline cracks,

probably caused by thermal expansion or contraction of the concrete, should be ignored.

Indicate if there are any CORRODED (10% volume loss), MISSING OR BROKEN, or

LOOSE nuts at this connection if the BOLTS are EXPOSED. 

Record if the GATE OR VALVE CONNECTION IS OBSERVABLE. IF YES, record

the MOVEMENT at the END CONNECTION by visually observing any movement as

the chain goes from slack to full tension and estimating the movement to the nearest 1/8

in. (Figure 27). To further enhance the visual observation, place a dial gage at this

location.
144

  (10.1)

 (10.2)

 (10.3)

10.3 Condition Index

The following section contains the rules for calculating the individual CIs for

the chain assembly distresses. Distress descriptions and example illustrations are

also provided.

Noise, Jumping, and Vibration

See noise, jumping, and vibration for the exposed gear assembly

(Chapter 4, p 51).

Linkage Wear/Elongation

Definition and cause. Linkage wear/elongation can be caused by the

reduction of cross-sectional area of chain links at the point of contact, wear of

the connecting pins and rollers, and elongation of the chain links. For roller

links, this wear occurs between the pin and the side plate and for round links

the wear occurs where the links interconnect (Figure 49). Linkage wear and

elongation are caused by normal operation of the chain assembly, through the

interaction between the chain links, misalignment of the sprocket, or

excessive loading.

Measurement and limits. The evaluation of chain link wear/elongation

will be accomplished by comparing the length of a new link to the current

chain link length. The difference, X1 , between the length of the new links,

XNEW, and the measured length, XWORN, is:

The percentage of wear, X, is:

The limiting value for linkage wear/elongation is:

(U.S. Army Corps of Engineers, 1987).
145





  

 

 

Example: In the inspection of a chain assembly, the measured distance

between pins of a roller link was:

The new distance between pins was:

Applying Equation 10.1 gives:

The percentage of wear/elongation in the chain is:

The CI for linkage wear/elongation is:

The CI is rated Good.

Cracks

See cracks for the exposed gear assembly (Chapter 4, p 54).

Frozen Links

Definition and causes. The links of a chain are frozen when they will not

bend properly around the sprocket or remain bent when loaded. Links may become

frozen when the gate is not moved frequently. Frozen links are caused by

inadequate lubrication and interaction with the environment (corrosion).

Measurement and limits. If the chain links in a chain set are frozen, it is

recorded in the inspection form. The CI will be 70 if there are frozen links, but the
146



 (10.5)



 

equipment is still operational. However, if the structure operation is limited due to

the frozen links, the CI will be 40.

Example: A chain assembly that was not operated often had several frozen links. 

The operation of the structure was not limited by the frozen links, therefore, the CI

for the frozen links distress is:

The CI is rated Good.

Corrosion/Pitting

See corrosion for the strut arm assembly (Chapter 7, p 101).

Sprocket Wear

Definition and causes. Sprocket wear is the wear of the sprocket teeth. This

wear occurs because of the interaction between the sprocket teeth and the chain

links. Normal use and lack of lubrication can cause sprocket wear.

Measurement and limits. Measurement of sprocket wear will be made by

estimating the percentage of reduction of original sprocket tooth, X. If the estimated

value of reduction is greater than 10 percent, a measured percentage of reduction, X,

is found. The limiting value for sprocket wear will be:

Example: The estimated percentage of reduction for a worn sprocket tooth was:

The CI for sprocket wear is:

Table 2 describes the CI for sprocket wear as Good.
147

Sprocket Anchorage Movement/Deterioration

See anchorage movement/deterioration for the exposed gear assembly

(Chapter 4, p 51).

End Connection Movement

See end connection movement for the strut arm assembly (Chapter 7, p 97).

Assembly CI

The assembly CI will be calculated with Equations 2.2, 2.5, and 2.6 (See

Chapter 2, Assembly Distress). The lone critical distress in the chain assembly is

the cracks distress. The CIs from the remaining eight distresses will be used to

calculate the weighted CIw (Equation 2.5). The weighting factors for those eight

distresses are in Table 19.

10.4 Field Test

The chain assembly was not observed during the first two field tests in the

Jacksonville and Louisville Districts; therefore, data to calibrate the rules in Section

10.3 could not be obtained. On the third field trip, the chain assembly was observed

and discussion with the experts was helpful in revising the inspection form and rules

for the chain assembly. The rules for similar distresses in other assemblies were

used as guidelines for the rules in Section 10.3.

Noise, Jumping, and Vibration

The noise, jumping, and vibration distress was calibrated for the enclosed gear

assembly, and those calculated CIs closely approximated the experts’ average CIs.

Linkage Wear

The linkage wear distress could not be calibrated but was tested during the

third field test. The technique described in Section 10.2 seemed to work reasonably

well. The value of XMAX in Section 10.3 was obtained from the Safety and Health

Requirements Manual (USACE 1987).
148

Cracks

Although the cracks distress could not be calibrated, the experts felt that

cracks in a chain assembly were critical and should be repaired. The rule for the

cracks distress in Section 4.3 corresponds well with the collective expert opinion.

Frozen Links

Although the frozen links distress could not be calibrated, the experts felt that

frozen links in a chain assembly were serious and should be repaired. The rules for

the frozen links distress in Section 10.3 correspond well with the collective expert

opinion.

Corrosion/Pitting

The corrosion/pitting distress could not be calibrated for the chain assembly.

The rule for the corrosion distress was, however, calibrated for the strut arm

assembly and the calculated CIs closely approximated the experts’ average CIs.

Sprocket Wear

Although the sprocket wear distress could not be calibrated, the inspection

questions and rules were written to closely resemble the questions and rules for

cable drum wear that were presented in Chapter 9.

Sprocket Anchorage Movement/Deterioration

The sprocket anchorage movement/deterioration distress could not be

calibrated for the chain assembly. The anchorage movement/deterioration distress

was, however, calibrated for the exposed gear assembly (Section 4.4) and the

enclosed gear assembly (Section 5.4).

End Connection Movement

Although the gate connection movement distress could not be calibrated for

the chain assembly, the distress was calibrated for the strut arm assembly. The

calculated CIs closely approximated the experts’ average Cis.

Assembly CI

Although the combined CI could not be calibrated for the chain assembly, the

weighting factors used to calculate the assembly CI (Table 19) were obtained from

the experts.
149

11 Hydraulic Cylinder

Assembly

11.1 Component Identification

Definitions and sketches for components of a hydraulic cylinder are presented

in the following paragraphs.

Hydraulic Cylinder

Hydraulic cylinders produce the force required to move the gate structure or

lift and lower the valve structure. Hydraulic cylinders are often used horizontally in

gate structures (Figures 5 and 37). Hydraulic cylinders are also used horizontally in

conjunction with the rocker assembly in valve structures (Figure 6) . In some cases,

the hydraulic cylinders are used vertically directly above a vertical lift valve (i.e.,

therefore, a rocker arm is not needed).

Packing Plate

The function of the packing plate is to allow the piston rod to pass through the

cylinder end without leakage of hydraulic fluid. The packing plate is at the end of

the hydraulic cylinder (Figure 6).

Piston Rod

The piston rod extends from the hydraulic cylinder and transfers the force

from the hydraulic cylinder to the strut (Figure 6).

End Connection

The end connection is located at the end of the piston rod. Its function is to

transfer force from the piston rod to the strut, rack, or rocker (Figure 6).

Anchorage

The anchorage transfers the load from the hydraulic cylinder to the concrete

base (Figure 6).
150

Guides

In some cases, the hydraulic cylinder rod has guides to support the cylinder.

11.2 Inspection Form With Comments

The following pages are Parts 1 and 2 of the field inspection forms for the

hydraulic cylinder assembly. The side-by-side arrangement of the opposing pages

displays specific explanations (right side) adjacent to the entry on the inspection

form (left side).
151

Intentionally Blank
152

U.S. ARMY CORPS OF ENGINEERS P.T.#: 

HYDRAULIC CYLINDER INSPECTION PART 1

PROJECT NAME: 

DATE: 

GATE IDENTIFICATION: (identify the appropriate structure)

Lock Gate

Upper 1. Left Leaf 2. Right Leaf

Lower 1. Left Leaf 2. Right Leaf

Valve

Emptying 1. Left 2. Right

Filling 1. Left 3. Right

Dam Gate

Number 

NOISE, JUMPING, AND VIBRATION IS IT NORMAL

NOISE (Y/N) (Y/N) 

JUMPING (Y/N) (Y/N) 

VIBRATION (Y/N) (Y/N) 

ANCHORAGE MOVEMENT/DETERIORATION

MOVEMENT: (Y/N) 

CORROSION: (Y/N) 

CRACKED CONCR.: (Y/N) 

EXPOSED BOLTS: (Y/N) -----> IF YES (Y), 

CORROSION: (Y/N) 

MISSING OR

BROKEN NUTS: (Y/N) 

LOOSE NUTS: (Y/N) 

END CONNECTION MOVEMENT OPEN CLOSED

(estimate movement (in.): 0, 1/8, 1/4, 3/8, 1⁄2): 

 

CORROSION/PITTING OF ROD

SURFACE CORROSION: (Y/N) 

PITTING: (Y/N) IF YES, # OF PITS(per worst foot): 

LOCATION: 

DAMAGED ROD

PERCENT OF ROD WHICH IS SCORED: 

LOCATION: 

PEELING OF CHROME: (Y/N) 

OTHER SIGNIFICANT DAMAGE: (Y/N) 

IF YES, EXPLAIN: 

OIL LEAKAGE

EVIDENCE OF RECENT OIL LEAKAGE: (Y/N) 

NUMBER OF OIL DROPS PER STROKE: 

DRIFT 

DRIFT (in.): 
153

Part 1 Comments: Field data

Enter the PROJECT NAME on which the inspection will be performed, the DATE of the

inspection, and for the GATE IDENTIFICATION, identify whether this is a lock gate,

valve, or dam gate. Also enter the power transfer number (P.T.#), which can be found on

Page 1 of the inspection form.

Observation of the hydraulic cylinder assembly during gate or valve movement is a good

indicator of problems. Record any indication of NOISE, JUMPING, and/or

VIBRATION during operation and then indicate whether this noise, jumping, and/or

vibration is NORMAL.

Record any evidence of MOVEMENT greater than 0.002 in. at the ANCHORAGE as the

gate or valve is opened and closed. Evidence of movement can be observed visually or

enhanced by placing a dial gage to monitor any movement (Figure 50). Excessive

concrete spalling may indicate a displacement occurred at this location at some time. 

Also, record the presence of any CORROSION (10% volume loss) of the steel portion or

any CRACKED CONCRETE at the interface of the embedment. Small hairline cracks,

probably caused by thermal expansion or contraction of the concrete, should be ignored.

Indicate if there are any CORRODED (10% volume loss), MISSING OR BROKEN, or

LOOSE nuts at this connection if the BOLTS are EXPOSED.

Record any relative MOVEMENT in the END CONNECTION between the rod and the

attached component such as the rocker arm (Figure 27) , strut, cross head, etc., by

visually observing any movement parallel to the cylinder and estimating the movement to

the nearest 1/8 in. To further enhance the visual observation, place a dial gage at this

location.

Record evidence of any SURFACE CORROSION on the cylinder rod. If corrosion is

present, check to see if PITTING of the rod has occurred. If so, record the number of pits

in the worst foot along the length of the rod. Also record the LOCATION of the surface

corrosion from the connection end.

Wipe the rod clean and observe and record the PERCENTAGE of the cylinder ROD that

is SCORED greater than 1/64 in. Scoring is grooving along the length of the cylinder

rod. Also record the LOCATION of the scoring from the connection end. If applicable,

record the PEELING of CHROME from the surface of the rod. Also, indicate whether

any other SIGNIFICANT DAMAGE to the rod (such as nicks, bowing of the rod, etc.)

has occurred.

Record any EVIDENCE OF RECENT OIL LEAKAGE. Record the NUMBER OF OIL

DROPS that leak from the packing seal interface during one full STROKE (Figure 50). 

Many times this can be accomplished by placing a sheet of paper below the cylinder end.

Record the amount of DRIFT or movement of the hydraulic rod. When the hydraulic

cylinder is used for valve or dam gate operation, the valve or dam gate should be in the

open position. When the hydraulic cylinder is used to operate a lock gate, the lock gate

should be in the open position. Isolate the cylinder by closing all oil valves and

measuring the drift in a 15-min interval with a ruler or a dial gage (Figure 50).
154

U.S. ARMY CORPS OF ENGINEERS P.T.#: 

HYDRAULIC CYLINDER INSPECTION PART 2

DAMAGED GUIDE 

ARE ANY GUIDES USED IN THE HYDRAULIC CYLINDER ASSEMBLY? (Y/N) 

IF YES,

DOES ASSEMBLY SLIDE SMOOTHLY?: (Y/N) 

ARE GUIDES DAMAGED?: (Y/N) 

IF YES, IS THE HYDRAULIC CYLINDER BEING DAMAGED? (Y/N) 

COMMENTS: 

 

 
155

H Y D R A U L IC

 C Y L IN D E R

P IS T O N 

ROD

P A C K IN G 

P L AT E

C R AC KE D C O N C R E T E 

IN S P E C T IO N A R E A

E N D C O N N E C T IO N

MOVEMENT

H Y D R A U L IC

 C Y L IN D E R P IS T O N R O D

D IA L G A G E

P A C K IN G P L AT E

O IL L E A K A G E 

AREA

RULER O R

D IA L G A G E

S ID E V IE W

Figure 50. Hydraulic cylinder assembly distress measurements.

Part 2 Comments: Field data

Record if ANY GUIDES ARE USED IN THE HYDRAULIC CYLINDER ASSEMBLY. IF

YES, record if the GUIDES SLIDE SMOOTHLY. Also record if the GUIDES ARE

DAMAGED. If the guides are damaged, record if THE HYDRAULIC CYLINDER is BEING

DAMAGED.
156

 (11.1)

 

11.3 Condition Index

The following section contains the rules for calculating the individual CIs for

the hydraulic cylinder assembly distresses. Distress descriptions and example

illustrations are also provided.

Noise, Jumping, and Vibration

See noise, jumping, and vibration for the exposed gear assembly (Chapter 4, p

51).

Anchorage Movement/Deterioration

See anchorage movement/deterioration for the exposed gear assembly

(Chapter 4, p 51).

End Connection Movement

See end connection movement for the strut arm assembly (Chapter 7, p 97).

Surface Corrosion/Pitting of Rod

Definition and cause. Surface corrosion involves the scaling of steel material

on the surface of the cylinder rod due to interaction with the environment. If this

interaction continues, pitting will occur. Pitting is the minor loss of steel in

localized areas. Surface corrosion and/or pitting on the cylinder rod can be

detrimental to the end seals in the hydraulic cylinder.

Measurements and limits. Because any amount of corrosion on a cylinder rod

can cause damage to the hydraulic cylinder seals, the CI will be 85 for any evidence

of corrosion, including surface corrosion. For the condition of pitting, X is counted

to be the number of pits per worst foot of rod. The limiting number of pits is:

The CI for a rod with any amount of pitting can never be greater than 70.

Example: Ten pits were found on a cylinder rod during an inspection. The CI based

on the number of pits is:
157



 (11.2)



 

However, the CI can not be greater than 70 if any pits are found; therefore,

The CI is rated Good.

Damaged Rod

Definition and cause. Scoring of the rod refers to grooving that occurs in the

cylinder rod. During normal use, a cylinder rod will wear in a uniform pattern of

grooves. The causes for scoring include inadequate lubrication and normal wear

during the opening and closing motion. The hydraulic rod is sometimes surfaced

with chrome to protect the rod from interaction with the environment. With normal

use and exposure to the surrounding environment, the chrome sometimes peels off. 

Other damage such as nicking of the rod surface or bending of the rod is also

possible. This damage could result from misuse of the equipment.

Measurement and limits. The percentage of surface area of the rod that has

scoring greater than 1/64 in., X, and the location of these grooves are recorded on

the inspection form. Only the percentage of scoring is used in determining the condition of the rod. The limiting value for percentage of scoring is:

If there is evidence of chrome peeling off, the CI will be reduced by a factor of 0.70. 

If there is other significant damage to the rod such as chips or nicks, the CI will be

reduced by a factor of 0.55.

Example: Scoring greater than 1/64 in. was found on 50 percent of a cylinder rod

during an inspection of a hydraulic cylinder assembly. Some of the chrome surface

on the rod was peeling off. For the scoring distress:

Using Equation 2.1 and the value of XMAX from Equation 11.2, the CI for scoring is:
158

 

 (11.3)

 

The CI is further reduced because of peeling of the chrome. The CI for damage of

the rod is:

The CI is rated Marginal.

Oil Drippage

Definition and cause. Oil drippage can occur at or near the packing plate in

the hydraulic cylinder. Excessive cylinder pressure, damage to the rod, or wear of

the packing plate from normal use can be the cause of oil drippage.

Measurement and limits. The number of oil drops, X, that leak from the

packing seal interface are recorded in the inspection form. The limiting value for the

number of drops during a full stroke is:

If there is evidence of recent leakage, the CI can be no larger than 85.

Example: Twelve drops of oil leaked from the packing plate of a hydraulic cylinder. 

The CI for oil drippage is:

The CI is rated Marginal.

Drift

Definition and cause. When a structure uses a hydraulic cylinder and all oil

valves are closed, little movement of the supported load is expected. Drift distress is

the movement of the hydraulic rod with maximum load on the rod. For valve

structures with horizontal cylinders, the load is the dead load of the structure when

suspended. For sector gear and rack systems (Figure 5), there is normally no dead

load is due to the structure, but conditions due to water flow, wind, etc. may create a

load condition at the time of the inspection. On a sector gate, the load may be

caused by water head or water flow as the gate is opened.
159

 (11.4)

 (11.5)

 (11.6)



 

Measurement and limits. The total amount of drift, X, is the movement

recorded in a 15-min interval. The limiting value for drift for a valve structure

(loaded) is:

The limiting value for a lock gate structure (nonloaded) is:

The limiting value for a dam gate structure (loaded) is:

Example: The amount of drift found in a hydraulic cylinder used for valve operation

was:

The CI for drift in this hydraulic cylinder is:

From Table 2, the CI for drift is rated Poor.

Damaged Guides

Definitions and causes. Cylinder guides can become corroded over time. 

Guide anchorages can also deteriorate or become loose. When this occurs, the guide

assembly no longer moves smoothly as the hydraulic cylinder is operated. 

Corrosion and deterioration of the guides can be caused by interaction with the

environment.

Measurement and limits. If the guide does not slide smoothly as the

hydraulic cylinder is operated, it is recorded in the inspection form. The CI will be

70 if the guide does not slide smoothly. If there is damage to the guides , the

damage is also recorded in the inspection form. The CI will be 40 if damage can

occur to the hydraulic cylinder because of the damaged guides.
160



Example: The guide of a hydraulic cylinder jerked as the assembly was being

operated. The CI for guides is:

The CI is rated Excellent.

Assembly CI

The assembly CI will be calculated with Equations 2.5 and 2.6 (see Chapter 2,

Assembly Distress). The experts did not consider any of the distresses for the

hydraulic cylinder critical; therefore, Equation 2.5 will be used to calculate the

assembly CI. The weighting factors for the hydraulic cylinder distresses are in

Table 20.

11.4 Field Test

The bar charts in Figures 51 to 54 compare the experts' subjective CI from the

field tests to the CI calculated from the rules in Section 11.3 for four hydraulic

cylinder distresses. Only data from assemblies with observed distresses are plotted. 

Comparisons between the calculated and experts’ CIs are summarized below.

Noise, Jumping, and Vibration

The noise, jumping, and vibration distress was not calibrated because no noise,

jumping, or vibration in hydraulic cylinders was observed. Hence, the calculated

CIs were all 100, and the experts’ average CIs were 90 or above. The noise,

jumping, and vibration distress was calibrated in the enclosed gear assembly, and the

calculated CIs closely approximated the experts’ averages.

Anchorage Movement/Deterioration: Figure 51

In only one case (Ortona Vertical Lift Gate #4) was any anchorage deterioration observed (corrosion of nuts). The calculated CI was 85. For the other hydraulic

cylinder assemblies, no deterioration was recorded by the experts and the calculated

CI was 100.
161

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

100

O DV 4

CONDITION INDEX

Model Exp. Avg. Exp. Max. Exp. Min.

Figure 51. Anchorage movement/deterioration: hydraulic cylinder assembly.

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

100

O DV 3 O DV 4

CONDITION INDEX

Model Exp. Avg. Exp. Max. Exp. Min.

Figure 52. Corrosion/pitting of rod: hydraulic cylinder assembly.
162

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

100

O DV 3 O DV 4

CONDITION INDEX

Model Exp. Avg. Exp. Max. Exp. Min.

Figure 53. Oil leakage: hydraulic cylinder assembly.

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

100

O DV 3 O DV 4 C VT URM

CONDITION INDEX

Model Exp. Avg. Exp. Max. Exp. Min.

Figure 54. Drift: hydraulic cylinder assembly.
163

End Connection Movement

The end connection movement distress was not calibrated because no movement between the rod and rocker arm or cross heads in hydraulic cylinders was

observed. Hence, the calculated CIs were all 100 and the experts’ average CIs were

90 or above. The end connection movement distress was calibrated in the strut arm

assembly.

Corrosion/Pitting of Rod: Figure 52

The calculated CI for the corrosion/pitting of the rod closely approximated the

expert average. At the two locations where the distress was observed (Vertical Lift

Dam Gate #3 Ortona and Vertical Lift Dam Gate #4 Ortona), the CI compares very

well to the experts’ numbers, with a difference of less than 5 points for each.

Damaged Rod

The damaged rod distress was not calibrated because no damage was observed

in the hydraulic cylinders. Hence, the calculated CIs were all 100, and the experts’

average CIs were 90 or above.

Oil Leakage: Figure 53

The calculated CIs for oil leakage varied slightly from the experts’ average

CIs. On two hydraulic cylinders, oil leakage was evident. On one of these cylinders

(Ortona Lift Gate #4), the experts’ average was closely approximated by the

calculated CI. On a similar cylinder (Ortona Lift Gate #3), for which the same

number of oil drops per cycle was observed, the calculated CI was the same. The

experts’ average CI, however, was 16 points higher.

Drift: Figure 54

The calculated CIs for drift closely approximated the experts’ average CI with

the exception of one hydraulic cylinder (Filling Valve Cannelton) for which the

difference was 17 points.

Assembly CI: Figure 55

The assembly CI for the hydraulic cylinder assembly was calibrated for three

assemblies. The model CIs closely approximated the experts’ average CIs for all

three calibrated assemblies.
164

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

100

O DV 3 O DV 4 C VT UR

CONDITION INDEX

Model Exp. Avg. Exp. Max. Exp. Min.

Figure 55. Hydraulic cylinder assembly CI.
165

12 Coupling Assembly

12.1 Component Identification

Definitions and sketches for components of the coupling assembly are

presented in the following paragraphs.

Coupling

A coupling is a joint between input and output shafts that generally contains

meshing teeth to transfer force from one shaft to another (Figure 7). The meshing

teeth are enclosed in a hub.

Shaft

The shaft transfers force from one set of gears to another set of gears or to

other equipment such as a cable drum (Figure 7). The input shaft is the shaft on the

power end.

Hub

The hub is the casing that contains the meshing teeth of the coupling.

Keyway

The keyway enables the transmission of torque from a shaft to the shaftsupported element.

12.2 Inspection Form With Comments

The following page is the field inspection form page for the coupling

assembly. The side-by-side arrangement of the opposing pages displays specific

explanations (right side) adjacent to the entry on the inspection form (left side).
166

U.S. ARMY CORPS OF ENGINEERS P.T.#: 

COUPLING INSPECTION 

PROJECT NAME: 

DATE: 

GATE IDENTIFICATION: (identify the appropriate structure)

Lock Gate

Upper 1. Left Leaf 2. Right Leaf

Lower 1. Left Leaf 2. Right Leaf

Valve

Emptying 1. Left 2. Right

Filling 1. Left 2. Right

Dam Gate

Number 

NOISE, JUMPING, AND VIBRATION IS IT NORMAL

NOISE (Y/N) (Y/N) 

JUMPING (Y/N) (Y/N) 

VIBRATION (Y/N) (Y/N) 

CRACKS

NUMBER OF CRACKS: 

CORROSION

SIGNIFICANT CORROSION: (Y/N) 

SEVERE PITTING OR GENERAL THICKNESS REDUCTION: (Y/N) 

IS THE COUPLING FLEXIBLE(F) OR RIGID(R): 

IS THERE RELATIVE MOVEMENT BETWEEN THE INPUT SHAFT AND HUB? (Y/N) 

IF YES, IS THE MOVEMENT EXCESSIVE? (Y/N) 

IS THERE RELATIVE MOVEMENT BETWEEN THE OUTPUT SHAFT AND HUB? (Y/N) 

IF YES, IS THE MOVEMENT EXCESSIVE? (Y/N) 

COMMENTS: 

 
167

Comments: Field Data

Enter the PROJECT NAME for this inspection, the DATE of the inspection, and, for the

GATE IDENTIFICATION, identify which gate or valve is being inspected. Also enter

the power transfer number (P.T.#), which can be found on Page 1 of the inspection form.

Observation of the coupling during gate or valve movement is a good indicator of

problems. Record any indication of NOISE, JUMPING, and/or VIBRATION during

operation and then indicate whether this noise, jumping, and/or vibration is NORMAL.

The presence of CRACKS on the coupling is usually not tolerated. Record the

NUMBER OF CRACKS found by visual observation of these components. 

The presence of excessive CORROSION on the coupling is a potential problem. Record

YES if there is SIGNIFICANT CORROSION (more than general scaling). If yes,

indicate if there is SEVERE PITTING (1/8 in. pits or greater) in a dense pattern or

GENERAL THICKNESS REDUCTION of 10% or greater in local areas. Carefully

observe the keyways (if there are any) for corrosion.

A FLEXIBLE COUPLING is an internal gear (Figure 56). A small amount of lateral

movement of the coupling may occur in a flexible type coupling. A RIGID COUPLING

is one for which no movement should occur, either in the lateral direction or with respect

to the shaft. Rigid couplings are often bolted together.

Observe the shaft and hub when the operating equipment starts and stops. Record if there

is any RELATIVE MOVEMENT BETWEEN THE INPUT SHAFT AND the HUB. 

Also record any RELATIVE MOVEMENT BETWEEN THE OUTPUT SHAFT AND

the HUB. If either distress is marked yes, record if THE MOVEMENT IS EXCESSIVE. 

If the coupling has a keyway, and the key is loose or there is obvious long-term

movement, the movement is excessive.
168

S HAFT

B O LT S

R IG ID C O U P L IN G

S HAFT

F L E X IB L E C O U P L IN G

R E L AT IV E M O V E M E N T

R E L AT IV E M O V E M E N T

Figure 56. Coupling relative movement measurement.

12.3 Condition Index

The following section contains the rules for calculating the individual CIs

for the coupling assembly distresses. Distress descriptions and example

illustrations are also provided.

Noise, Jumping, and Vibration

See noise, jumping, and vibration for the exposed gear assembly (Chapter

4, p 51).

Cracks

See cracks for the exposed gear assembly (Chapter 4, p 54).
169



Corrosion

See corrosion for the strut arm assembly (Chapter 4, p 101).

Input Shaft and Hub Movement

Definitions and causes. As the coupling becomes worn, relative

movement between the input shaft and the hub begins to take place. As this

wear becomes worse, the potential for failure becomes greater. Relative

movement can be caused by normal use, inadequate lubrication, or corrosion.

Measurements and limits. If relative movement between the input shaft

and hub are observed, it is recorded in the inspection form. If relative movement

is observed, the CI will be 70. If the movement is excessive, the CI will be 40.

Example: Relative movement between the input shaft and hub was observed on

a coupling assembly. The CI for the relative movement between input shaft and

hub is:

The CI is rated Good.

Output Shaft and Hub Movement

See input shaft and hub movement for the coupling assembly (above).

Assembly CI

The assembly CI will be calculated with Equations 2.2, 2.5, and 2.6 (See

Chapter 2, Assembly Distress). The three critical distresses in the coupling

assembly are the cracks distress, the relative movement between the input shaft

and hub distress, and the relative movement between the output shaft and the

hub distress. The CIs from the remaining two distresses will be used to calculate

the weighted CIw (Equation 2.5). The weighting factors for those two distresses

are in Table 21.

12.4 Field Test

The bar chart in Figure 57 compares the experts' only subjective CI from

the field tests with the CI calculated from the rules in Section 12.3 for the one
170

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

100

WP LS UR WP LS LR

CONDITION INDEX

Model Exp. Avg. Exp. Max. Exp. Min.

Figure 57. Input shaft and hub movement: coupling assembly.

coupling distress type inspected and rated. Only data from assemblies with

observed distresses are plotted. Comparisons between the calculated and

experts’ CIs are summarized below.

Noise, Jumping, and Vibration

The noise, jumping, and vibration distress was not calibrated because no

noise, jumping, or vibration in couplings was detected. Hence, the calculated

CIs were all 100, and the experts’ average CIs were 90 or above. The noise,

jumping, and vibration distress was calibrated in the enclosed gear assembly and

those calculated CIs closely approximated the experts’ average CIs.

Cracks

The cracks distress was not calibrated because no cracks were observed in

the couplings. Hence, the calculated CIs were all 100, and the experts’ average

CIs were 90 or above. Although this distress was not calibrated, the experts felt

that cracks in the coupling were critical and should be repaired, which

corresponds well to Section 4.3.

Corrosion

The corrosion distress was not calibrated because corrosion was not

observed in couplings. Hence, the calculated CIs were all 100, and the experts’

average CIs were 90 or above. The corrosion distress was calibrated in the strut
171

assembly, and the calculated CIs closely approximated the experts’ average CIs.

Input Shaft and Hub Movement: Figure 57

Figure 57 shows CI ratings for relative movement between input shaft and

hub distress for two sector lock gate operating equipment assemblies, both

located at W.P. Franklin. Relative movement was observed in couplings

between the reduction gear box shaft and the cable drum shaft. The experts’

average CI for the coupling on the Upper Right Lock Gate is lower than the

calculated CI. For the coupling on the Lower Right Lock Gate, the relative

movement was less noticeable than on the Upper Right Lock Gate; hence, the

experts’ average CI was higher, and matched the calculated CI more closely.

Output Shaft and Hub Movement

The relative movement between output shaft and hub distress was not calibrated because no relative movement between the output shaft and hub in

couplings was detected. Hence, the calculated CIs were all 100, and the experts’

average CIs were 90 or above. The relative movement between input shaft and

hub was calibrated (Section 12.4).

Assembly CI

The coupling assembly was not one of the assemblies on the inspection

form during the field test at the Jacksonville District; therefore, the experts did

not subjectively rate the coupling assembly CI for the two cases where relative

movement was observed. Although the combined CI could not be calibrated for

the coupling assembly, the weighting factors used to calculate the assembly CI

were obtained from the experts (Table 21).
172

13 Summary and

Recommendations

The inspection and rating procedures described in the previous chapters

were kept as simple as possible. Most of the inspection procedures require

simple tools such as a tape measure, a dial gage, a ruler, a caliper, or a pry bar. 

In all cases, the inspection procedure can be accomplished with little

interference to normal lock and dam operations.

An inspection form, written to accommodate the inspection procedure,

was completed in two sections. On the first, historical information, maintenance

history, and current operating characteristics are recorded. Field measurements

found during the inspection procedure are recorded in the second section.

After field measurements are obtained, computer software will be written

to generate the CI for each of the individual distresses and for each assembly. 

The CI is a number between 0 and 100 that quantifies the current condition of

the assembly. The CIs generated with the software are used to determine when

maintenance or rehabilitation is required. The rules used for the computation of

the CIs were developed with the help of Army Corps of Engineers experts.

CIs are calculated for the individual distresses associated with each

assembly. The distress CIs are used to calculate the assembly CIs using the

minimum of a weighted average or the individual CI of a distress considered

critical to the structural stability of the assembly.

Field tests were conducted at 16 lock and dam facilities during three trips. 

Revisions to the inspection and rating procedures and to the inspection forms

were completed following each of the field tests.
173

References

Committee of Wire Rope Producers. 1979. Wire Rope Users Manual, American Iron and Steel

Institute, Washington D.C. 20036

Department of the Army Hydroelectric Design Center, North Pacific Division, Army Corps of

Engineers. 1993. Condition Rating Procedures/Condition Indicator for Hydropower

Equipment, Army Corps of Engineers, Portland, Oregon.

Greimann, L., and J. Stecker, December 1990. Maintenance and Repair of Steel Sheet Pile

Structures, Technical Report REMR-OM-9/ADA2231916. U.S. Army Corps of Engineers,

Washington, D.C.

Greimann, L., J. Stecker, and K. Rens, December 1990. Management System for Miter Lock Gates,

Technical Report REMR-OM-08/ADA231469. U.S. Army Corps of Engineers,

Washington, D.C. 

Greimann, L., J. Stecker, and K. Rens, September 1993. Condition Rating Procedures for Sector

Gates, Technical Report REMR-OM-13/ADA279299, U.S. Army Corps of Engineers,

Washington, D. C. 

Greimann, L., J. Stecker, and J. Veenstra, March 1994. Condition Rating Procedures for Tainter

and Butterfly Valves, Technical Report REMR-OM-14/ADA279326, U.S. Army Corps of

Engineers, Washington, D.C.

Greimann, L., J. Stecker, and M. Nop, September 1995. Condition Rating Procedures for Tainter

Dam and Lock Gates, Technical Report REMR-OM-17/ADA303294, U.S. Army Corps of

Engineers, Washington, D.C.

Shigley, J., and C. Mischke, 1989. Mechanical Engineering Design, Fifth Edition, McGraw-Hill

Inc., New York, NY.

U.S. Army Corps of Engineers. 1987. Safety and Health Requirements Manual, Engineer Manual

385-1-1. U.S. Army Corps of Engineers, Washington, D.C.

Wilson, C., and J. Sadler, 1993. Kinematics and Dynamics of Machinery, Second Edition, Harper

Collins College Publishers, New York, NY.
174

Appendix A

Bushing Wear Jacking

Procedure

Introduction

The procedure and calculations described in this appendix can be used to

further evaluate the bushing wear in large horizontal gears if tipping is evident. 

When applying the following technique, care must be taken not to apply too

much force to the gear. Overloading the gear during the jacking procedure could

cause serious damage to the bushing system. This procedure should never be

performed on gears with bearings, as damage may occur.

Procedure

Place three dial gages to measure the vertical displacement in the gear

(Figure A1). Place one dial gage at the center of the gear. The remaining two

dial gages should be placed an approximately equal distance, X1 and X2 , from

the center of the gear and as close to 180 degrees from each other as possible

(Figure A1). To prevent errors in readings, place all dial gage plungers in the

same direction. Record the initial dial readings for all dial gages. Place a jack

near one of the dial gages and begin jacking. Precaution should be taken while

jacking the gear to ensure overloading does not occur. Record the dial gage

readings after jacking (Figure A2). Next, release the jack and again take the dial

gage readings. Place the jack 180 degrees from the initial position (near the

other dial gage) and again jack and record the dial gage readings (Figure A3). 

Release the jack and record the dial gage readings.
175

G EAR BAS E

RO LLER RAC K G EAR

JAC K

(P O S IT IO N 1 ) 

R E A C T IO N

RO LLER

D IA L G A G E 2

X 1 X 2

JAC K

(P O S IT IO N 2 ) 

D IA L G A G E 1

C ENTER

D IA L G A G E 

X 1 X 2

D IA L G A G E 1

D IA L G A G E 2

C E N T E R D IA L G A G E 

P L A N V IE W

S E C T IO N V IE W

Figure A1. Bushing wear measurement.

X 1 X 2

D 2 1 D 1 1 1

Figure A2. Vertical displacements when jacked on Side 1.
176

X 1 X 2

D 2 2

D 1 2 2

Figure A3. Vertical displacements when jacked on Side 2.

Calculations

If no bowing occurs in the gear, the total angle of rotation of the gear

during the procedure, O, is found by calculating O1 (the angle caused by jacking

at position 1) and O2 (the angle caused by jacking at position 2):

O = O1 + O2

The following equation can be used to calculate O1:

O1 = (D11 - D21)/(X1 + X2)

where D11 is the difference in dial gage 1 readings between the initial gear

position and the gear position after the being jacked at position 1,

D11 = Gage 1 reading (initial) - Gage 1 reading (jacked at 1)

where D21 is the difference in dial gage 2 readings between the initial gear

position and the gear position after the being jacked at position 1,

D21 = Gage 2 reading (initial) - Gage 2 reading (jacked at 1)

Similarly, for O2:

O2 = (D12 - D22)/(X1 + X2)
177

D C e n te rM e a s u re d

D C e n te rC a lc u la te d

Figure A4. Displaced shape of gear (bowed and unbowed).

where D12 is the difference in dial gage 1 readings between the initial gear

position and the gear position after the being jacked at position 2,

D12 = Gage 1 reading (initial) - Gage 1 reading (jacked at 2)

where D22 is the difference in dial gage 2 readings between the initial gear

position and the gear position after the being jacked at position 2,

D22 = Gage 2 reading (initial) - Gage 2 reading (jacked at 2)

Assuming that there is no bowing of the gear, the calculated displacement at the

center of the gear, DCenterCalculated , should be equal to the average of the

displacements of the dial gages located 180 degrees from each other, D1 and D2:

DCenterCalculated = (D1 + D2)/2

If, however, bowing of the gear does occur, DCenterCalculated will not be equal to the

measured displacement at the center, DCenterMeasured (Figure A4). To prevent

bowing, which introduces stresses into the gear, the jacking should not continue

if DCenterMeasured varies significantly from DCenterCalculated. If bowing has occurred, too

much force is being applied to the gear during the jacking procedure.

Limits

The limiting value for vertical displacement of an exposed gear that rotates

on a bushing is 1/16 in. per foot of gear radius. This corresponds to an angle of

rotation of 0.0026 radians or 0.15 degrees.
178

P IT C H 

L IN E

NEW TOOTH W ORN TOOTH

 W O RN TO OTH 

 T H IC K N E S S NEW TOOTH 

T H IC K N E S S

AD D EN D U M

DEDENDUM

C LEARAN C E

W HO LE 

DEPTH

W O R K IN G

DEPTH

ROOT

C IR C L E

P IT C H

C IR C L E

C LEARAN C E

C IR C L E

Figure B1. Gear tooth dimensions and wear measurement.

Appendix B

Gear Tooth Wear Measuring

Procedures

Introduction

If the estimated percentage of tooth thickness reduction from the new tooth

thickness is 10 percent or greater, the tooth should be measured to get a more precise

estimate of tooth wear. This appendix explains tooth thickness measurement

techniques.

Gear and Rack Tooth Identification

To inspect and rate gear and rack tooth wear, familiarity with the nomenclature used in describing gear and rack teeth is necessary; definitions for the various

tooth relationships are presented in the following paragraphs and shown in Figure

B1.
179

Addendum

The radial distance from the pitch line to the top of the gear.

Dedendum

The radial distance from the pitch line to the root circle.

Clearance

The radial distance from the clearance circle to the root circle.

Whole Depth

The radial distance between the root circle and the top of the gear.

Tooth Thickness

The width of the tooth at the pitch line.

Working Depth

The radial distance from the top of the gear to the clearance circle.

Diametral Pitch (DP)

The number of teeth of a gear divided by the diameter of the pitch circle in

inches.

Circular Pitch (CP)

The arc distance measured along the pitch circle from a point on one tooth to

the corresponding point on the adjacent tooth of the gear. The following equation

relates the diametral and circular pitch: _ = (CP)(DP).

Root Circle

The circle drawn through the bottom of the gear tooth.
180

System Addendum Dedendum Clearance

Whole

Depth

Tooth

Thickness

14 1⁄2 full-depth

involute

 1/DP 1.157/DP 0.157/DP 2.157/DP 1.571/DP

14 1⁄2 composite 1/DP 1.157/DP 0.157/DP 2.157/DP 1.571/DP

20 full-depth

involute (coarse

pitch)

 1/DP 1.25/DP 0.25/DP 2.25/DP 1.571/DP

20 full-depth

involute (fine pitch)

 1/DP 1.2/DP +

0.002 in

0.2/DP +

0.002 in 

2.2/DP +

0.002 in

1.571/DP

20 stub-tooth

involute

 0.8/DP 1/DP 0.2/DP 1.8/DP 1.571/DP

25 full-depth

involute

 1/DP 1.25/DP 0.25/DP 2.25/DP 1.571/DP

(Wilson and Sadler, 1993)

Table B1. Gear tooth relationships.

Clearance Circle

The largest circle centered at the gear center, which is not penetrated by the

teeth of the mating gear.

Pitch Circle

The circle on a gear that corresponds to the center of the working depth.

Table B1 shows the relationship between the DP and the addendum, the

dedendum, the clearance, the whole depth, and the tooth thickness for six commonly

used standard gear profile systems.

Procedure 1

Begin by finding the tooth pitch line. In some cases, the pitch line is scribed

on the tooth during the manufacturing process. If the pitch line can be seen, place a

caliper on the top of the tooth with a spacer placed between the caliper and the top of

the tooth (Figure B2). The caliper points should be on the pitch line, one on each

side of the tooth. With the caliper now at the correct depth, slide the caliper along

the length of the tooth. Find the location of the tooth where the tooth thickness at

the pitch line is the smallest. Record this measurement. If the pitch line is not

scribed on the tooth, calculate the addendum of the tooth by use of the construction

drawings and Table B1. As shown on Figure B1, the addendum is the distance from

the top of the tooth to the pitch line. Use the addendum to calculate the required

spacer thickness. With the spacer in place, follow the same procedure as described
181

P IT C H 

L IN E

C A L IP E R

S PAC E R

Figure B2. Gear tooth wear measurement: Procedure 1.

above. Next, calculate the new tooth thickness. The new tooth thickness can be

calculated from the DP, which can be found in construction drawings, and Table B1. 

In some cases, the CP may be listed in the construction drawings instead of the DP. 

The relationship between the CP and the DP can be found in the gear tooth

definitions.

Procedure 2

If gear tooth templates are available during the inspection, place the template

between gear teeth. With the use of feeler gages, measure the gap between the

template and the gear tooth at the pitch line. If the pitch line is not scribed on the

tooth, locate the pitch line by calculation of the addendum as described in Procedure

1.

Calculations

If the estimated reduction of tooth thickness is 10 percent or greater, the

measured thickness reduction should be entered in Part 2 of the inspection form for

the Exposed Gear Assembly and the Rack Assembly. The percentage of tooth
182

thickness loss can be calculated using the following equation if Procedure 1 was

used.

% thickness reduction = 1 - (Worn thickness)/(New thickness)

If Procedure 2 was used, the following equation will calculate the percentage of

tooth thickness loss.

% thickness reduction = (Measured Gap)/(New Thickness)

Examples

Calculation of the Addendum(Location of the Pitch Line)

The pitch line of a tooth can be found by calculating the addendum of the

tooth using Table B1. The distance from the top of the tooth to the pitch line is the

addendum. A 20-degree involute stub tooth gear with a diametral pitch of 0.75/in.

was inspected. The addendum of the tooth is:

addendum = (0.8)/(.75/in.) = 1.067 in.

The distance from the top of this tooth to the pitch line is equal to 1.067 in.

Calculation of New Tooth Thickness

The construction drawings of a gear that is being inspected show P = 1.5/in. 

From the last column of Table B1, the tooth thickness for the gear is:

tooth thickness = (1.5708)/(1.5/in.) = 1.0472 in.

Relationship Between CP and DP

Construction drawings show CP = 3.1416 for an exposed reduction gear. The

corresponding DP is:

DP = (_)/(3.1416) = 1

Note: For helical and herringbone (double helical) gears, the same relationships

apply (Shigley and Mischke 1989). Helical and herringbone gears are generally

coarse pitched; therefore, if this information is not given, assume it is coarse pitched. 
183

If the pressure angle is not given, the standard helical gear has the same relationships

as the 20-degree, coarse pitch gear shown in Table B1.