problems has resulted in the inspection procedure for tainter gates described in the
remainder of this chapter.

Overview of Inspection Procedure

Many Corps districts follow an annual schedule to inspect gates. Annual
inspections are usually performed under normal operating conditions. Normal
operating conditions refers to the usual status of the gate structure at the time of
inspection. For example, the gate may be operating under load conditions or it may
be dry. The amount of time and degree of detail spent on such inspections vary
considerably among different districts. Some districts will place bulkheads every
five years in order to conduct a thorough inspection and to perform any necessary
maintenance. Some inspect only representative gates. Working within this estab-
lished schedule, the ISU project team has developed an inspection procedure to
handle the conditions under which the inspections will be performed. Generally
speaking, an inspection performed under bulkheaded conditions gives a more
accurate assessment of gate condition than inspections done during normal operat-
ing conditions; however, bulkheaded inspections are costly and require more time.
Because of this, an inspection performed under normal operating conditions is the
initial procedure in the evaluation process. The information gathered from this type
of an inspection is used to calculate an initial CI. Generally, inspections performed
under normal operating conditions will continue until a gate is bulkheaded for
maintenance reasons or the initial CI value becomes low enough to warrant further
investigation. To get a more accurate assessment of a gate’s condition, an inspec-
tion should be performed under bulkheaded conditions in order to update the CI.
This updated CI can be used to evaluate the approximate condition of other gates
operating under similar conditions.

Overview of Inspection Form

The inspection form for tainter dam and lock gates has been designed to
provide flexibility in documenting a variety of field conditions within one standard
form. The first two pages of the form address historical information and should be
completed before the field inspection. The remaining four pages are completed in
the field. The following paragraphs briefly outline the inspection form.

Historical Information

Historical information related to the tainter gate structure is recorded on pages 1
and 2 of the inspection form. Project reference data is recorded to identify and
locate the specific structure. Information that categorizes the structure into a

Chapter 2 Field Inspection

1



32

3 Condition Index

The common definition of a Cl as it relates to all the structures investigated thus
far by the ISU and other project teams is shown in Table 1 of Chapter 1. Engineer-
ing judgment and experience are needed to develop the set of criteria from which
the CI of a structure will be established. The process of identifying this set of
criteria for tainter dam and lock gates was similar to the procedure used for other
structures. Interviews and discussions held between the ISU project team and Corps
experts continued until a general approach for tainter gate inspections began to
develop. Preliminary field visits and meetings with engineers took place at Red
Rock Dam on the Des Moines River and at the Rock Island District Office; Ice
Harbor Lock and Dam on the Snake River; Old Hickory Dam on the Cumberland
River; David D. Terry Lock and Dam 6 on the Arkansas River; Greers Ferry Dam
and Powerhouse on the Little Red River; and Lower St. Anthony Falls Lock and
Dam, Lock and Dam 2, 4, and 5A on the Mississippi River. Serviceability or
performance and subjective evaluation of safety were the primary factors consid-
ered by the experts. Their opinions have been combined and classified by the
authors into a set of problems or distresses and “expert opinion” rules that are
embedded in the evaluation that constitutes the CI. The distresses are used to
organize straightforward, visual observation data for interpretation by the rules in
the same manner that a seasoned engineer would interpret field observations. The
rules will continue to evolve.

During the development of the dam gate rules, the experts assumed that the
integrity of the dam gates is critical. The experts assumed the gates must function at
all times, and that no backup system (except for bulkheads) is available. The loss of
pool has serious consequences for navigation, power generation, and flood control.

The distresses identified for tainter gates are quantified by a measurement X.
These measurements can consist of actual data-taking or are the result of a subjec-
tive evaluation. Experts were asked to interpret these measurements in light of the
serviceability and safety of a tainter gate and to assign limiting values to the
measurements.

Typically, each distress can be either a problem in itself or an indication ofa
problem. For example, anchorage movement is a problem in itself if it is suffi-
ciently large to impede tainter gate operation; otherwise it can be an indication of a
potential structural problem. The individual distress CI is quantified by

Condition Index = 100(0.4)"TM= (3.1)

Chapter 3 Condition index



U.S. ARMY CORPS OF ENGINEERS PAGE 5
TAINTER DAM AND LOCK GATE STRUCTURE INSPECTION

CORROSION (C) or EROSION (E)

COMPONENTS COR SECT MAX. AVG
E THICK DEPTH DEPTH

% or NO. AVG
AREA | PITS DIA
|
l

US SKIN PLATE
- TOP

- SPLASH ZONE | |

- BOTTOM 2' | |

DS SKIN PLATE | |

RIBS | |

GIRDERS | |

STRUT ARMS | |

BRACING | |

TRUNNION GIRDER | |

TRUNNION HUB | |

TRUNNION YOKE i |

SEAL'G SURFACE STL. 1 |

LIFTING BRACKET | |

HAIN PI WEAR

IS THERE A BEARING PLATE ATTACHED TO THE SKIN PLATE? Y N
IF YES, WHAT IS THE ORIGINAL BEARING PLATE THICKNESS:
OTHERWISE WHAT IS THE ORIGINAL SKIN PLATE THICKNESS:

IS THE WEAR VISIBLE? Y N

IF YES, CIRCLE THE MAX. DEPTH OF WEAR:
LEFT SIDE (in.) 0 1/32 1/16 1/8 1/44 3/8 1/2
RIGHT SIDE (in.) 0 1/32 1/16 18 1/4 3/8 1/2

28 Chapter 2 Field Inspection



Chapter 3

Misalignment Distress
Definition and Causes

The misalignment distress refers to the misalignment of the gate between the
piers or lockwalls as it is lifted. The skin plate may begin to twist or even hang up
on the pier or lockwall. The three principle causes of this distress are:

* cable or chain tension
* trunnion problems
* pier shifting.

The operating machinery used to lift the gate is often designed to self-adjust the
amount of tension in the cables or chains on either side of the gate as it is lifted.

Measurement and Limits

Measurements can be made using tape measures or an electronic level. Tape
measures are used to measure a vertical distance from the skin plate to a fixed
reference point for the closed, X,, and 2-ft open positions, Xp. The distance each
edge of the skin plate rises is the difference between the closed and 2-ft open
positions.

Xy = Xo - Xo (3.2)

The height differential between the edges of the skin plate, X, is the difference
between the distance each edge rose.

X = Kuen ~ Xcrign! (3.3)

When a level is used, the inclination angle of the skin plate is recorded. The
absolute value of the difference in the angles for the closed, A,, and the 2-ft open,
Ap, positions is used to determine the difference in height between each edge of the
skin plate as

X = W tan(A, - Aj) (3.4)

where W is the width of the gate. The limiting horizontal misalignment of the
vertical edge for a gate of any height was judged to be 0.25 in. Larger values may

Condition Index

37


‘oeuiayos Wep pue 490] JajUIe) “Z eunB4



Dents (Figure 23)

The only dents recorded in the field test (three on the skin plate and one on the
ribs) were on Gate 10 at Lock and Dam 5A. The calculated CI describing the dent
condition was 14 points lower than the expert average for this gate. This calculated
CI was controlled by the rib dent; however, the CI calculated for the skin dents was
only two points higher at 76. As future inspections are performed, it may be
necessary to increase the value of X,,,, to better reflect the condition of a gate. The
more conservative X,,,, is appropriate at this time.

100 — —
va A We A LK Na RAL

90+ NT N ~ kx

804 N NI

LY

no

oo

so

404

ao

204

10

° Gote 1 Gate 2 Gate 8 Gote 10 Gate 9 Gate 10 gate 1 Lock Gate

LOCK & DAM 2 LocK & paM 4 LOCK & DAM SA LOW. ST. ANTHONY FALLS
[exe ave Z)modet PR exp. tox. exe tan

Figure 23. Dents.

Corrosion/Erosion (Figure 24)

No corrosion or erosion was recorded on Gate 1 at L&D 2 and the gates at
Lower St. Anthony Falls. The expert average for Gate 1 at L&D 2 cannot be
accounted for by the authors. Strut arm corrosion was the controlling CI for Gate
10 at L&D 4 and the gates at L&D 5A. The calculated CI for Gate 10 at L&D 4
compared well with the expert average. The gates at L&D 5A, however, had
calculated Cls that were substantially lower than the expert average. The calculated
Cl values for Gate 2 at L&D 2 and Gate 8 at L&D 4 correspond relatively well with
the expert averages. The corrosion was recorded on the inspection form using
primarily the percentage area method.

Chapter 4 Field Testing



Crack Distress
Definition and Causes

Cracks usually represent a narrow opening, break, or discontinuity in the
structural steel members. Cracks are caused by:

* fatigue
* brittle fracture
* overstressed 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.

Measurements and Limits

The number of cracks in the upstream skin (U), downstream skin (D), ribs
(R), main girders (M), bracing (B), strut arms (S), trunnion hub (H), trunnion
yoke (Y), or trunnion girder (G) are recorded on the inspection form. Length
and location of cracks also are recorded but are not used in the calculation of
the CI. For cracks on the main girders, ribs, bracing, upstream skin plate, and
downstream skin plate, the limiting values are

Xam = 1 (3.24)
Xnor = 1 (3.25)
Xnaca = 1 (3.26)
Xa = 3 (3.27)
Xnup = 3 (3.28)

The individual CIs for these components are calculated using Eq. 3.1.

The limiting values of cracks are handled differently for the remaining
components. These components include the strut arms, trunnion girder,
trunnion hub, and trunnion yoke. If a crack is present in these components, it
could critically affect the overall structural integrity of the gate. The experts

Chapter 3 Condition Index

47



The limiting value of the total motion is also the same regardless of the
conditions under which the inspection is performed and whether the
movements are short- or long-term:

Xpaxtor = 0-125 in, (3.19)

The CI for trunnion assembly wear will be the minimum of the CIs
calculated for the lateral and total movement.

CI = Minimum (Cl,ypClrop) (3.20)

The following two sections will describe how to calculate the horizontal and
vertical short-term and long-term movements for the different inspection
conditions.

Xyors) = Maximum (XypXp3) (3.21)

Normal operating conditions: Either dial or feeler gauge measurements
must be made in order to monitor short-term horizontal, Xjors), and vertical,
Xvexsy» Movements. If dial gauges are used, the short-term horizontal and
vertical movements are the difference between the 2-ft open and the closed
position readings. If feeler gauges are used, the short-term horizontal motion
is the maximum of the movements measured in either the upstream gap, Xys,
or the downstream gap, Xps. The movements in the upstream and downstream
gaps are the absolute difference between the 2-ft. open and the closed feeler
gauge measurements, X, and X, respectfully.

Xys = Kos - Xous! (3.22)

Xps = Kos - Xows! (3.23)

Similarly, the short-term vertical motion is the maximum of the movements
measured in the top, Xyop, and bottom, Xgo7, gaps.

The horizontal and vertical long-term displacements are determined using
trammel measurements by taking the difference between the maximum and
minimum inspection distances since the last repair.

Bulkheaded conditions: The short-term displacements are found in the same
manner as under normal operating conditions, except that the feeler or dial gauge

Chapter 3 Condition Index

45


Localized deterioration also takes place in the form of galvanic corrosion.

When dissimilar metals are placed in a conductive solution, a potential difference
exists. This situation arises when gates, constructed primarily of structural steel,
have stainless steel components attached. Structural steel has a different electrical
potential than stainless, and electron flow is toward the more resistant material.
Therefore, structural steel acts as the anode and stainless as the cathode.

Most light corrosion has little structural significance. However, extensive
deterioration can sufficiently reduce the steel cross-sectional area so that stresses are
significantly increased.

Measurement and Limits

To measure the amount of material loss due to corrosion or erosion, the one
square foot with the greatest material loss is selected. The material loss in this
square foot should be designated as corrosion (C) or erosion (E). The average
pitting depth, D, and the average pitting diameter, d, are recorded. Within the
square foot, either the percent of area, P, that is affected or the number of pits, N, is
recorded. Information for this distress is recorded for a variety of tainter gate com-
ponents: upstream skin (U), downstream skin (D), strut arms (S), trunnion girder
(G), main girders (M), ribs (R), and bracing (B). Corrosion on the upstream skin is
measured at the top (UT), splash zone (UZ), and bottom 2 ft (UB). The X value for
this distress is the percent volume of steel loss due to corrosion. If the percentage
area of the selected square foot that is pitted is entered, the percent volume loss is

-PxD
T

x (3.39)

where T is the steel plate thickness. If the number of pits is recorded, the area of
one pit is

2
Area of | pit = =24 (3.40)
Since there are N pits with an average depth, D, the volume loss is
2
Volume loss = Naszesb 3.41)
If inch units are used to record the material loss, the percent volume loss is
Volume loss
X = 100 x ————_ (3.42)
144xT (3.42)

Chapter 3 Condition Index 51



For non-power plant applications, submersible tainter dam and lock gates have a
limiting value of

Xnaxs = 30% (3.49)

and non-submersible have a limiting value of

Xnaw = 10% (3.50)

Example: From an inspection of a submersible lock gate, the leak length along
the sides was 2 ft with a wetted side perimeter of 32 ft. The percentage length of
leaks around the wetted perimeter was

x = 2400) = 63%
32

The CT is calculated to be

CI = 100(0.4)°3TM = 83

From Table 1, this CI is very good.

Seal Condition Distress
Definition and Causes

When seals are damaged or sections are missing, it allows water to leak around
the wetted perimeter of the gate. Seal damage is caused by several factors:

* floating debris
© improper lifting
* normal use over time.

Measurement and Limits
Seals are visually inspected for damaged and missing sections. The length and
location of these sections are recorded. The experts judged that the seal condition

distress is not sufficiently important to be included in the CI although damage
should be recorded.

Chapter 3 Condition Index

55



during the first bulkhead inspection because the anchorage system will relax under
the no-head condition. The displacement, X,, is calculated by taking the difference
between the maximum and minimum distances (bulkheaded and normal operating
conditions). The limiting long-term anchorage movement is given by Eqs. (3.8) and
(3.9). :

Example: Measurements of anchorage movement were taken during an
inspection performed under bulkheaded conditions. When the bulkhead was
removed, the amount of head present on the gate was 45 percent. From dial gauge
readings, the rigid anchorage assembly had a short-term movement of

X, = 0.019 in.

The long-term maximum movement was

X, = 132 in.

which is the difference between the current full-head trammel measurement and a
critical trammel measurement from a previous inspection. The limiting short-term
motion for a rigid anchorage from Eq. (3.12) is

Xpauts) = (0.005 ) + xn m” % - 20% ) = 0.026 in.

The limiting long-term anchorage motion is from Eq. (3.8).

Xpaerty = UB in.

Cracked and spalled concrete was evident around the bearing plate. The Cl for
short-term rigid anchorage motion is

Cl, = [100(0.4)°°19TM5)0.85 = 44
where the 0.85 factor was used because the concrete was cracked and spalled. The

long-term CI is

Ch, = [100(0.4)°3"259.85 = 68

The CI, from Eq. (3.10), for overall anchorage assembly deterioration is

CI = Minimum (44,68) = 44

From Table 1, the CI is rated fair; that is, there is moderate deterioration of the
anchorage.

Chapter 3 Condition Index

43


Page 1 Comments: Historical or Recordkeeping Data

Completed before the site inspection and verified or changed during the site inspection.
Data blanks on page | prefaced by (no.)___ must be recorded as numbers.

Enter in the NAME of the Corps of Engineers Project Title.

Indicate the BODY OF WATER and NEAREST TOWN.

Indicate the CONDITIONS under which the inspection will be performed. A
NORMAL OPERATING condition refers to the usual status of the gate structure. For
example, the gate may be operating under load conditions or be in a dry condition.
BULKHEADED conditions imply that bulkheads will be placed to remove head or load
from the gate. After readings are recorded, the bulkhead is removed and full head is
applied. The inspection conditions will affect how anchorage and trunnion assembly
wear measurements will be taken. An inspection performed under normal operating
conditions may also prevent some information such as cable/chain plate wear from
being taken because it may not be visible.

Indicate FUNCTION AND LOCATION OF GATE, TYPE OF PROJECT, and GATE.

Indicate TYPE OF FRAMING, SKIN PLATE, and LIFTING SYSTEM by entering the
appropriate number in the blank following each question. A double skin plate has an
upstream skin plate and a downstream skin plate; a single skin plate can also be called
an upstream skin plate.

Enter the WIDTH, HEIGHT, and RADIUS of the tainter gate.

Enter the UPPER and LOWER POOL WATER LEVELS and the ELEVATION OF
SILL referenced to mean sea level. This is important for establishing the head on the
gate at the time of inspection. Bulkheading periods and construction information may
be important for reference.

Chapter 2 Field inspection

15



where X,,,, is some limiting value of X . The CI zones given in Table 2 define X,

max

as the point at which the CI is 40, that is, the dividing point between Zones 2 and 3.
In other words, the experts have chosen the limiting value X,,,, to be the point at
which a tainter gate requires immediate repair or, at least, a more detailed
inspection. Figure 13 illustrates the equation and zones from Table 2.

Table 2. Condition index zones.

Zone Cl Range Action
1 70-100 Immediate action not required
2 40-69 Economic analysis of repair alternatives recommended to
determine appropriate maintenance action
3 0-39 Detailed evaluation required to determine the need for
repair, rehabilitation or reconstruction, safety evaluation
recommended
100
90
80
ZONE 1
ba 70
a
a
Z 60
INI
z 50 ZONE 2:
=
B40
Zz
a
o 30
20 ZUNE, 3:
10
0
O01 02 03 04 05 06 0.708 09 10 11 12 13 14 15 16
X/X raax

Figure 13. Condition index related to XX...

Chapter 3 Condition Index

33


64

60-4

504

404

30+

Gote 1 Gate 2
LOCK & DAM 2

Gate 8  Gote 10 Gote 9 Gate 10

Gate 1 Leck Gate

LOCK & DAM 4 LOCK & DAM SA LOW. ST. ANTHONY FALLS

[Nene ave [oder BR exp. Max. exp. Hn

Figure 21. Trunnion assembly wear.

100

90-4

e0-|

704

604

«0

te 1 Gate 2
LOCK & DAM 2

Gote 6 — Gate 10 Gate 9 Gate 10

Gate 1 Lock Gate

LOCK & DAM 4 LOCK & DAN SA LOW. ST. ANTHONY FALLS:

[lex ave. nose exe. tox Sexe Hn

Figure 22. Cracks.

Chapter 4 Field Testing



Trunnion Assembly Wear
Cracks

5 Structural Considerations ........ 26.06. e cece cence een eee eee 69

6 Summary and Recommendations

References 06... cece cece eee ene e eee enter ee 72

Accesion For

NTIS CRA& x
DTIC TAB
Unannounced o
Justification

By |
Distribution |

Availability Codes

. Avail and] or
Dist Special

Al



7 =

"TN N ‘ / yo

oo Ly m R) rf 7} 4 me

4 My oY 1 L, D

© MI N %N aN

wo L WA BN (4

wo

: NV Ny

%
204 Dm
104 Dt
%

° Gate 1 Gate 2 Cote 8 Gote 10 Gote 9 Gote 10 Gate 1 Lock Gate

LOCK & DAM 2 Lack & DAM 4 LOCK & DAM SA LOW. ST. ANTHONY FALLS

[exp ave. )Moaet PR exp. Max. [Q) Exp. Min

Figure 25. Leaks.

100
| Bom h& Rh o Te VY
4 2 a sy
eo N NENG N BL
N < Mf
70-4 N Mt
oo
lk
wl K i"
404 r
| IN WK p
204 »
e
of
° Gate 1 Gate 2 Gote 8 Gate 10 Gote 9 Gote 10 Gate 1 Lock Gote
Looe & ma 2 nck & DAM 4 LOCK & DAM SA LOV. ST. ANTHONY FALLS

[Nex ave, moder Pl exp. Hox. exp. hn

Figure 26. Overall ratings for the gates.

Chapter 4 Field Testing

67



66

100 x
WR WER
904
N RQ x
0+ sy Ne,
N NI
70-4 g +X 7iKS
4 ~ Y

oo Ly

so ‘4

ao

204

204

104

oi Nwotel Gate 2 Gate ® Gate 0 Gate 9  Gote 10 Gate 1 Locie Gate

Lock & DAM 2 Lock & DAM 4 LOCK & DAM SA LOW. ST. ANTHONY FALLS
[ew ave. moder exo. tox Sexe. Hin

Figure 24. Corrosion/erosion.
Cable/Chain Plate Wear

Because cable/chain plate wear could not be observed, no CI calculations were
performed.

Leaks (Figure 25)

The gates at Lower St. Anthony Falls were submersible, and the expert average
closely approximated the calculated CI for these gates. The gates at the other sites
were nonsubmersible. No leaks were recorded at L&D 2 or at Gate 10 at L&D 4;
however, the expert average CI was less than 100, which cannot be explained by the
authors. Gate 8 at L&D 4 had a 1-in.-long leak and a wetted perimeter of 58 ft. At
L&D 5A, Gate 9 had a leak length totaling 12 in. and Gate 10 had a 2.5-in. leak. The
wetted perimeters on these gates were both 58 ft. In all three cases, the expert average
is lower than the calculated CI. The authors do not feel that the X,,,, for these types of
gates should be reduced at this time because the expert averages for these gates,
though consistently lower than the calculated CI, are highly variable among the gates.

Overall Gate Ratings (Figure 26)

The overall gate ratings from the calculated model tended to track higher than
the expert average, except for Gate | at Lower St. Anthony Falls, which was

Chapter 4. Field Testing



5 Structural Considerations

One of the primary factors taken into account by the experts during the devel-
opment of the CI rules was subjective safety. Subjective safety assumes that an
engineer is capable of using his or her judgment to detect a safety problem. Their
observations during an inspection may indicate that the potential for a problem
exists or that a safety problem is developing and may soon become critical. For
example, a crack in the strut arm almost certainly indicates a safety problem. A
more detailed inspection will reveal the seriousness of the situation. Deterioration
such as this usually is not accounted for in a classical structural analysis technique
and cannot be easily quantified.

The experts took many of these structural considerations into account when
assigning limiting values, tolerances, and weight factors for all the CI rules in
Chapter 3. However, certain distress measurements characterize the structural
adequacy of a gate more than others. This important subset of structural distresses
is listed in Table 5.

To alert an engineer that a potential safety problem could be developing or
already exists, these distresses are flagged with a structural note along with the
corresponding measurement, X. Three CI levels are used to characterize the
severity of the note. The levels and a typical note for anchorage assembly deteriora-
tion are as follows:

Level 1 Flag: 55<CI<70

Note: The anchorage movement was measured to be X inches and should be
monitored.

Table 5. Tainter gate structural distresses.

Structural Distress Brief Description
Anchorage assembly Embedded steel movement and concrete and steel deterioration
deterioration
Crack-strut arms Break in strut arms
Crack-trunnion girders Break in trunnion girder
Crack-main girders Break in main girders
Crack-trunnion hubs Break in trunnion hubs
Crack-trunnion yokes Break in trunnion yokes.
Corrosion-strut arms Loss of strut arm steel
Corrosion-main girders. Loss of main girder steel

Chapter 5 Structural Considerations

69



26

CONCRETE PIER

VERTICAL 4

[7 bral GAUGES

HORIZONTAL

TRUNNION
GIRDER

TRUNNION YOKE

Figure 9. Trunnion assembly wear measurement: dial gauges.

CONCRETE PIER

TRUNNION
GIRDER

STRUT ARMS

UPSTREAM

BOTTOM

Figure 10. Trunnion assembly wear measurement: feeler gauges.

Chapter 2. Field Inspection


12

particular type and function is requested. Some information is used to sort through
the expert rules in the evaluation process, such as gate dimensions. Entries for
historical descriptions of maintenance, modifications, and inspections are also
provided on page 2 for reference only.

Field Measurements

Pages 3 through 6 of the inspection form are used to record field measurements.
Some of the measurements requested include anchorage assembly deterioration,
trunnion assembly wear, cracks, dents, corrosion, cable/chain plate wear, misalign-
ment, noises, and vibrations. The expert rules described in Chapter 3 utilize these
field measurements to determine the CI for tainter gates.

General Notes
The actual inspection form for tainter gates is shown on the following pages.

Illustrations have also been provided to indicate how some of the measurements are
taken. Specific explanations for entries on the inspection form are provided on the

opposing page.

Chapter 2 Field Inspection



18

U.S. ARMY CORPS OF ENGINEERS PAGE 3
TAINTER DAM AND LOCK GATE STRUCTURE INSPECTION

OPENING AND CLOSING OF THE GATE
IS IT NORMAL?

NOISE? Y N Y N
JUMPING? Y N Y N
VIBRATION? Y N Y N
VIBRATION WITH FLOW

GATE VIBRATION (LEVEL 0, 1, 2, 3, or 4):
CAN VIBRATION BE ELIMINATED BY GATE OPENING ADJUSTMENT? Y N

MISALIGNMENT
HOW WILL MEASUREMENTS BE TAKEN? no.) 1. TAPE MEASURES
2. ELECTRONIC LEVEL
COMPLETE IF TAPE MEASURES ARE USED
CLOSED 2' OPEN CLOSED
LEFT EDGE (in.)
RIGHT EDGE (in.)

COMPLETE IF ELECTRONIC LEVEL IS USED

CLOSED 2' OPEN CLOSED
ANGLE (degrees)
ANCHORAGE ASSEMBLY DETERIORATION
LEFT SIDE RIGHT SIDE

CONCRETE CRACKED OR SPALLED? Y N Y N
BOLTS/NUTS: CORRODED? Y N Y N

LOOSE? Y N Y N

MISSING? Y N Y N

IS THE EMBEDDED ANCHORAGE FLEXIBLE OR RIGID? F R
IF FLEXIBLE, LENGTH OF EMBEDMENT (in.):

ANCHORAGE MEASUREMENT (Measurements are taken in the downstream
direction.)

COMPLETE IF NORMAL OPERATING CONDITIONS
LEFT SIDE (in.) RIGHT SIDE (in.)
CLOSED 2'OPEN CLOSED CLOSED 2'OPEN CLOSED
Dials
Trammels

COMPLETE IF BULKHEADED CONDITIONS
LEFT SIDE (in.) RIGHT SIDE (in.)
NO HEAD FULL HEAD NO HEAD FULL HEAD
Dials
Trammels

Chapter 2 Field Inspection



14

U.S. ARMY CORPS OF ENGINEERS PAGE 1
TAINTER DAM AND LOCK GATE 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:
INSPECTION CONDITIONS:

1. NORMAL OPERATING

2. BULKHEADED (no.
FUNCTION AND LOCATION OF GATE:

1.DAM

2. LOCK (no.
TYPE OF PROJECT:

1, POWERPLANT

2. NON-POWERPLANT no.)
TYPE OF GATE:

1, SUBMERSIBLE

2. NON-SUBMERSIBLE (no.)
TYPE OF FRAMING:

1. HORIZONTAL

2. VERTICAL (no.)
TYPE OF SKIN PLATE:

1. SINGLE

2. DOUBLE (no.
TYPE OF LIFTING SYSTEM:

1, CHAIN

2. CABLE no.)
GATE WIDTH: (ft) GATE HEIGHT: (ft)

GATE RADIUS: (ft)

UPPER POOL: (ft) LOWER POOL: (ft)
ELEVATION OF SILL: (ft)

DO YOU ROUTINELY BULKHEAD THE GATE? (Y/N) __ IF YES, WHAT YEAR

WAS THE GATE LAST BULKHEADED? INTERVAL PRD.?
CONSTRUCTION DATE:

Chapter 2 Field Inspection



VV

CONCRETE PIER

HORIZONTAL

feel + TRAMMELS,
4
|

VERTICAL

TRUNNION

TRUNNION
UB GIRDER

TRUNNION YOKE

Figure 11. Trunnion assembly wear measurement: trammels.

CONCRETE
PIER

LATERAL

MOVEMENT

<<. >»
I x Ay

TRUNNION YOKE
TRUNNION GIRDER <

—————————|

Figure 12. Trunnion assembly wear: lateral movement.

Chapter 2 Field Inspection

27



Prestressed anchors: In many cases, prestressed anchors are used to attach the
trunnion girder to the pier.

Lifting chain or cable: The lifting chain or cable connects the operating
machinery with the gate (Figure 3). It moves the gate between its open and
closed positions.

Lifting bracket: The lifting brackets are located near the bottom of the gate on
either the upstream or downstream side of the skin plate. They connect the
chain or cable to the gate structure (Figures 3 and 4).

Cable or chain bearing plate: A bearing plate is a thickened or doubled strip
of the skin plate or back-to-back channels located on the upstream side

(Figure 4). It reduces the wear on the skin plate caused by the sliding contact of
the cable or chain as the gate is moved.

Seals: Rubber seals are used on each side and sometimes on the bottom of a
gate to prevent leakage around the gate perimeter (Figure 5).

Rubbing plates: Steel side-seal rubbing plates are placed in the pier or lock-
wall to maintain a smooth contact surface for the side seals as the gate is moved
(Figure 5).

Diagonal bracing: Diagonal bracing is commonly used across the downstream
flanges of the main girders (Figure 4). It aids in the field erection of the gate
and adds to its rigidity.

Strut bracing: The strut bracing acts as an internal truss framework (Figure 3).
The specific arrangement of the members varies from gate to gate.

Chapter 1 Introduction



68

slightly lower. The primary reason that most calculated CIs were higher is that the
experts based their overall gate rating on the lowest individual distress Cls, gener-
ally leak and corrosion CIs, without considering the other distresses.

Summary

Overall, the calculated CIs tracked fairly well with the expert ratings. Two very
good discussion sessions were held with experienced Corps of Engineers experts to
develop the framework for the rules and to establish Xj values. The initial set of
rules will require continual monitoring as the inspection procedure is put into use.

There are a few shortcomings regarding the development of the rules and the
field test. First, the field calibration involved only five experts. If one of the five
gives a much different rating, the average is affected significantly by that individ-
ual.

Also, the gates that were inspected were generally in very good condition. The
expert ratings and the calculated CIs were both quite high relative to Zone 3 in
Table 1. The result is that the rating system was calibrated only for the upper range
of the CI scale. A more complete calibration of the CI scale could have been
achieved if one or more of the gates would have been in worse condition.

Finally, more testing and calibration should be performed. Although several
field tests were performed, improvements in the rules may be required to better
portray the experts’ evaluation of a gate condition. However, at this point it is
justifiable to implement the procedure in its current state and allow the rules to
evolve as Corps personnel apply them.

Software has been written to automatically calculate the Cls, using data from
the inspection form (Chapter 2) and the rules in this chapter. The software is also
capable of maintenance and repair analysis with evaluation of repair alternatives by
economic analysis and consequence modeling. User implementation is similar to
steel shéet pile, miter lock gates, sector gates, and emptying and filling valves.

Chapter 4 Field Testing



and the percent volume loss is calculated from Eq. (3.42).

X, = 100 x —1% __ = 3.6%
144 x 0.375
The limiting value from Eq. (3.44) is
Xnaxp = 20%

The CI for the lower portion of the downstream skin is

Cly = 1000.45 = 85

From Table 1, this CI is rated excellent.

Cable/Chain Plate Wear Distress
Definition and Causes

Cable or chain plate wear is a loss of steel material on the bearing plate or skin
plate of a gate. The wear is caused by the sliding contact between the cable or chain
and the surface it bears on while the gate is being raised or lowered.

Measurement and Limits

Measurement of this distress is based on the reduced thickness of the bearing
surface. The X value is the maximum percent of wear depth on the bearing surface.
If a bearing plate is attached to the skin plate, only the thickness of the bearing plate
is used to determine the percent of wear depth. The limiting amount of depth loss
for a bearing plate is

Xnaxgp = 50% (3.46)

When a bearing plate is not present, the skin plate acts as the bearing surface and
the limiting percent of wear depth is

Xnaxsp = 25% (3.47)

If the depth of wear can not be measured or is not visible, the CI for this distress can
not be calculated and is, therefore, not included in the combined gate CI.

Chapter 3. Condition Index 53



1 Introduction

Background

Over the past 100 years the U.S. Army Corps of Engineers has designed and
constructed numerous civil works structures such as locks and dams on the naviga-
ble inland waterways and coastal systems and dams for power generation. Re-
cently, however, the potential for such undertakings has become limited, and the
need for maintenance of the present facilities has become more significant. The
Corps has responded by initiating and developing a Repair, Evaluation, Mainte-
nance, and Rehabilitation (REMR) program.

A research effort concentrating on the inspection and rating of tainter dam and
lock gates has been developed by the project team at Iowa State University (ISU).
As part of the REMR program, the research has established a consistent means of
identifying potential problems for tainter dam and lock gates through the use of an
inspection procedure. With this tool the engineers have the capability to analyze
and evaluate the inspection information before problems become severe.

Being able to rely on the functionality and structural integrity of tainter dam and
lock gates as operating components of a navigation lock and dam, or a power dam
facility, or a reservoir is essential. If a tainter lock gate does not work properly,
navigation along the entire river may be held up, incurring large user costs. Tainter
dam gates are critical for maintaining the upper pool and for use in flood control at
lock and power dam facilities. If a dam gate fails, causing the loss of pool, naviga-
tion along an entire stretch of river may be at a standstill until the pool is restored.

A power dam project faces decreased power generation capacity if head is lost.

Objective

The objective of this project was to develop an inspection and rating procedure
that describes the current condition of tainter dam and lock gates in a uniform
manner.

Chapter 1 Introduction



U.S. ARMY CORPS OF ENGINEERS PAGE 4
TAINTER DAM AND LOCK GATE STRUCTURE INSPECTION

TRUNNION ASSEMBLY WEAR

LEFT SIDE RIGHT SIDE
ANY PROBLEMS WITH THE LUBRICATION SYSTEM? Y N NA Y N NA

INDICATE HOW VERTICAL AND HORIZONTAL MEASUREMENTS WILL BE
TAKEN: no.) 1, FEELER GAUGES & TRAMMELS
2. DIAL GAUGES & TRAMMELS

COMPLETE IF NORMAL OPERATING CONDITIONS
LEFT SIDE (in.) RIGHT SIDE (in.)
CLOSED 2'OPEN CLOSED CLOSED 2'OPEN CLOSED
HORIZONTAL:
Dials
Feeler US
DS
Trammel
VERTICAL:
Dials
Feeler TOP
BOT

LATERAL: 0 1/16 1/8 1/4 3/8 1/2 O 1/16 1/8 1/4 3/8 1/2
IS ANY GOUGING NOTICEABLE? Y N YN

COMPLETE IF BULKHEADED CONDITIONS

LEFT SIDE (in.) RIGHT SIDE (in.)
CLOSED 2'OPEN CLOSED CLOSED 2'OPEN CLOSED

HORIZONTAL:
Dials
Feeler US

DS
Trammel
VERTICAL:
Dials
Feeler TOP

BOT

LATERAL: 0 1/16 1/8 1/4 3/8 1/2 O 1/16 1/8 1/4 3/8 1/2
IS ANY GOUGING NOTICEABLE? Y N YN

Chapter 2 Field Inspection



60

lq— 9 Ft. 2 Ft. >

5.75 Ft.

BOX
TRUNNION
W-BEAM GIRDER

LOCK WALL

—>
DOWNSTREAM

MOUNTING PLATE FOR >

TRUNNION YOKE
4

Figure 17. Flexible anchorage at lower St. Anthony Falls.

The following bar charts (Figures 18 to 25) present the experts’ subjective CI
versus the Cl calculated by Chapter 3 rules for the distresses associated with tainter
dam and lock gates. Each graph is for an individual distress. Within each group of
data are four columns of data that represent

* expert average

¢alculated CI (Chapter 3 rules)
highest index assigned by an expert
* lowest index assigned by an expert.

The results of a comparison between the expert rating and the calculated values for
each distress are summarized below. In addition, there is a comparison for the
overall CI of each gate (Figure 26).

Chapter 4 Field Testing



62

00
NZ uN N gy Wan 0 N
94 N Ny N
80+ N NI N A
nd 1.
oo
so
ol
304
zo
vod
° Gate It Gate 2 Gate 8 Gate 10 Gate 9 Gote 10 Gote 1 Lock Gate
Looe «ban 2 nex & an a LOK 6 OA SALW. ST. ANTHONY FALLS
[ieee ave ZDaoset exp. toe Kleen nn

Figure 19. Vibration with flow summary.

Misalignment

The misalignment distress was measured on each gate using tape measures.
However, the accuracy of the data collected was in question and, therefore, the
results were not plotted.

Anchorage Assembly Deterioration (Figure 20)

The calculated anchorage assembly CIs closely approximated the expert
averages, except for Gate 1 at L&D 2, Gate 8 at L&D 4, and the lock gate at Lower
St. Anthony Falls. Movements of 0.001 in. were recorded for Gates 1 and 8, which
result in a calculated CI of 83. The experts assigned a limiting X,,,, value of 0.005
in. for rigid anchorage motion under normal operating conditions. However, the
higher CIs assigned by the experts do not support the appropriateness of this
limiting value, and suggest that X,,,, should be increased. Nevertheless, the authors
feel that the movement is significant, especially because the load variation on the
gate is small under a normal operating condition, and that the calculated CI is
appropriate. The calculated CI for the lock gate at Lower St. Anthony Falls was
11 points lower than the expert average. The limiting value for flexible anchorage
movement is 0.065 in. using Eq. 3.16 with an embedment length, L, of 9 ft, which is

Chapter 4 Field Testing



100
“HA or —
oo A
w! BANNAN Nal NEN Nal aN by
nd
oo!
so!
wo!
ao!
a!
104
° Gate 1 Gate 2 Gate 8 Gate 10 Gate 9 Gate 10 Gate 1 Lock Gate
ee & ban 2 Loe & ban 4 LOCK Ba SA LOW. ST. ANTHONY FALLS
(Nex. avo, ZModet PR exp. Max. QJ Exp. Hin

Figure 20. Anchorage assembly deterioration.

the length of the W-beam (Figure 17). The movement measured during the inspec-
tion was 0.013 in. The calculated CI would more closely approximate the expert
average if the rule, which is based on an allowable axial deformation, included the
deformation of the 5-ft box trunnion girder. However, the authors feel that the
anchorage configuration is unique, and therefore an analysis is not warranted. Long
term movements could not be determined because only current readings were
available. The accuracy of trammel measurements may not be sufficient.

Trunnion Assembly Wear (Figure 21)

The calculated CIs for trunnion wear closely approximated the expert average
with the exception of Gate 1 at Lower St. Anthony Falls. The authors have no
explanation for the difference. Horizontal and vertical measurements were made
using feeler gauges at every site except at Lower St. Anthony Falls, where dial
gauges were used.

Cracks (Figure 22)

No cracks were recorded on any gate, resulting in a calculated CI of 100 for the
crack distress on each gate. Similar to the noise, jumping, and vibration distress,
though, the experts rated the gates slightly lower than 100.

Chapter 4 Field Testing

63



| Chapter 2 Field Inspection

This Page Intentionally Left Blank

21


Form Approved
OMB No. 0704-0188

REPORT DOCUMENTATION PAGE

Public reporting burden for this collection of information is estimated to average 1 hour per response, Including the time for reviewing Instructions, searching existing data Sources,
gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this
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T. AGENCY USE ONLY (Leave Blank) _[2. REPORT DATE
September 1995

3. REPORT TYPE AND DAT
Final

ES COVERED.

4. TITLE AND SUBTITLE

5. FUNDING NUMBERS

Condition Rating Procedures for Tainter Dam and Lock Gates Civil Works Research WU 32672

6, AUTHOR(S)
Lowell Greimann, James Stecker, and Michael Nop

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION

. oo. . REPORT NUMBER
U.S. Army Construction Engineering Research Laboratories (USACERL)
P.O. Box 9005

REMR-OM-17
Champaign, IL 61826-9005

‘9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES)
Headquarters, U.S. Army Corps of Engineers (HQUSACE)
ATTN: CECW-O
20 Massachusetts Avenue, NW.

Washington, DC 20314-1000

10. SPONSORING / MONITORING
AGENCY REPORT NUMBER

11. SUPPLEMENTARY NOTES:
Copies are available from the National Technical Information Service, 5285 Port Royal Road, Springfield, VA 22161.

12a. DISTRIBUTION / AVAILABILITY STATEMENT 12b. DISTRIBUTION CODE

Approved for public release; distribution is unlimited.

13, ABSTRACT (Maximum 200 words)

The mission of the U.S. Army Corps of Engineers has been shifting from constructing new facilities to maintaining the large
inventory of existing facilities. The objective of this work was to develop an inspection and rating system that uniformly and
consistently describes the current condition of tainter dam and lock gate structures.

The objective was achieved by conducting site visits and field investigations with experts from the U.S. Army Corps of
Engineers, and by using the experts’ opinions to develop the rules which form the basis of the rating system.

This document provides a general ‘description of the inspection and rating system, which includes the definition of a condition
index and a description of tainter gate distresses. This is followed by a detailed description of the inspection and rules for
calculating condition indexes for tainter gates.

14, SUBJECT TERMS
condition rating

15. NUMBER OF PAGES:
82

locks and dams

condition indexes
navigation structures

46. PRICE CODE

17. SECURITY CLASSIFICATION
OF REPORT

Unclassified

18. SECURITY CLASSIFICATION
OF THIS PAGE

Unclassified

19. SECURITY CLASSIFICATION
OF ABSTRACT

Unclassified

20. LIMITATION OF
ABSTRACT

SAR

IN 7540-01 -280-5500 Standard Form 298 (Rev. 2-89)
Prescribed by ANSI Std 239-18

298-102



Tables

Table 1. Condition index scale and zones
Table 2. Condition index zones
Table 3. Tainter dam and lock gate distresses
Table 4. Unadjusted weighting factors for tainter gate distresses ..
Table 5. Tainter gate structural distresses



Figures

Figure 1. Inspection and rating procedure ............. 20s sees eee e eee ee eee 3
Figure 2. Tainter lock and dam schematic
Figure 3. Side view of tainter gate
Figure 4. Elevation view of tainter gate
Figure 5. Side seal detail ....
Figure 6. Example trunnion assembly detail (individual projects differ
considerably)
Figure 7. Misalignment measurement
Figure 8. Anchorage measurement
Figure 9. Trunnion assembly wear measurement: di
Figure 10. Trunnion assembly wear measurement: feeler gauges .
Figure 11. Trunnion assembly wear measurement: trammels .

Figure 12. Trunnion assembly wear: lateral movement
Figure 13. Condition index related to X/X,,.. -
Figure 14. Percent head with tailwater
Figure 15. Percent head without tailwater
Figure 16. Weight adjustment factor for condition index ...
Figure 17. Flexible anchorage at lower St. Anthony Falls . .
Figure 18. Noise, jumping, and vibration . .
Figure 19. Vibration with flow summary . .
Figure 20. Anchorage assembly deterioration .
Figure 21. Trunnion assembly wear
Figure 22. Cracks
Figure 23. Dents ..
Figure 24. Corrosion/erosion
Figure 25. Leaks .. wees
Figure 26. Overall ratings for the gates . .



10

2 Field Inspection

Inspection Procedure Development

Simplicity and adaptability are the two ideas that form the basis of the inspec-
tion procedure. Applying the concept of simplicity to tainter dam and lock gates
means that the inspection program must be simple to learn and easy to execute in
the field. The inspection program must also be adaptable to both structures and the
conditions under which they function.

Previous work done by the ISU project team suggests that field inspection be
based upon easily obtainable data. Data that can be obtained from the pier, lock-
wall, or on the gate itself is considered to be easily obtainable. The safety aspect of
gathering data while on the gate was also an important consideration in the develop-
ment of the field inspection program. Each district takes special precautions to
ensure the safety of its workers. Some districts allow their personnel to walk
around on the gate if a safety harness is worn and some do not allow walking on the
gate, but will lower personnel down to a gate by means of a basket or platform.
Data is also considered easily obtainable if no underwater diving and ultrasonic or
other sophisticated devices are implemented. All data would be gathered using a
tape measure, a ruler, a trammel, dial gauges and the like. An interview with the
chief lock or dam operator will assist the collection of data. The intent of this
inspection procedure is that no specific engineering training or experience is needed
to perform an inspection, although the interpretation of the inspection results often
requires engineering expertise.

Gate configurations, function, project type, and operating conditions also affect
inspection procedures. Single-skin and double-skin gates are inspected differently.
The function of a tainter gate depends on whether it is a lock or dam gate. Power
plant and non-power plant projects have different applications that require different
rating rules. Operating conditions relate to the amount of head, if any, on the gate.
Each aspect affects the inspection procedure and rating rules to some degree. For
example, a gate that can be loaded first with full head and then have the head totally
removed gives the best indication of anchorage wear. However, this situation
seldom occurs, and the procedure for measuring wear is limited by the amount of
head on the gate at the time of inspection. Often the total amount of head cannot be
removed by placing bulkheads upstream to hold back the water, because it may be
impractical. Or, if bulkheads are used to isolate lock gates, navigation along a river
could be delayed if no auxiliary lock exists at the site. Addressing these types of

Chapter 2 Field Inspection



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 0929 square meters

vii



16

U.S. ARMY CORPS OF ENGINEERS PAGE 2
TAINTER DAM AND LOCK GATE STRUCTURE INSPECTION

IS THE ORIGINAL GATE CURRENTLY IN PLACE? (Y/N)
IF SO, WHAT YEAR WAS IT PUT INTO OPERATION?
IF NOT, IDENTIFY CURRENT GATE HISTORY:

ARE DRAWINGS AVAILABLE FOR THE GATE 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):,

A):

PREVIOUS INSPECTIONS OR STRUCTURAL REVIEWS (attach avail. copies)

DATE DESCRIPTION
(1):

(2):
(3):.
(4):

CONDITION OF LIFTING EQUIPMENT:

CONDITION OF GREASING SYSTEM:

OTHER COMMENTS:

Chapter 2 Field Inspection



US Army Corps

of Engineers
Construction Engineering
Research Laboratories

Technical Report REMR-OM-17
September 1995

REMR Management Systems—Navigation
Structures, Condition Rating Procedures for

Tainter Dam and Lock Gates

by Lowell Greimann, James Stecker, and Mike Nop
Engineering Research Institute

Approved For Public Release; Distribution Is Unlimited.

Prepared for Headquarters, US Army Corps of Engineers

19960117 022



Measurement and Limits

If anchorage movement becomes significant, it can be detected by visually
inspecting the interface around the anchorage connections. This is usually the first
indicator of a significant problem. Any structural cracking or spalling of the
concrete in this area will reduce the CI by a factor of 0.85. If any of the anchor or
casting bolts and nuts are corroded, loose, or missing, the CI decreases by a 0.70
factor. When more than one reduction factor is applicable, the CI is reduced by the
most severe reduction factor only.

Measurements of the anchorage movement are made between the concrete pier
or lockwall and the trunnion yoke or girder using dial gauges and trammels
(Figure 8). The measurements are made in the downstream direction to detect
elongated or broken anchor bolts, loose anchor nuts, or deterioration of the
anchorage system. Anchorage motion is divided into two categories: (1) short-term
movement and (2) motion over long periods of time. Short-term movement is
generally detected by changing the loading conditions on the gate at the time of
inspection in order to measure the amount of motion in the anchorage system.
Motion of the anchorage over time refers to the long-term displacements of the
trunnion girder. Short- and long-term motion measurements are made under two
distinct conditions: (1) normal operating conditions and (2) bulkheaded conditions.

Normal operating conditions: Dial gauge measurements are taken in the
closed and 2-ft open positions and then again in the closed position. The short-term
movement, Xg, is found by taking the difference between the 2-ft open and the
closed measurements.

Some embedded anchorage systems are designed to permit movement. These
types of anchorage configurations are called flexible anchorage systems. All other
anchorage systems are termed rigid. A short-term displacement of 0.005 in. has
been selected as the limiting motion at the steel and concrete interface for a rigid
anchorage.

Xnarrs) = 9-005 in. (3.6)

The limiting value for flexible anchorage motion is a function of the embedment

length, L, in inches.
Xnaxris) = 9.0001(L) (3.7)

The Corps experts judged that motion greater than this could indicate a significant
structural problem.

Chapter 3 Condition Index 39



Field Inspection

Figure 1 illustrates the inspection and rating procedure. The field inspection is
the means of gathering consistent data for any particular tainter dam or lock gate.
The first two pages of the inspection form are used to record descriptive data, such
as the type and location of the gate, general component information, and mainte-
nance history. Additional pages provide space for field measurement data, such as
anchorage assembly deterioration, corrosion, and cracks. The field measurement
data is representative of the current state of the structure. All the information
collected on the inspection form is entered into a data file on a microcomputer that
performs all the calculations necessary to rate the gate.

Field Inspection

'
Data Entry

'
Expert Rules

J

Condition Index

Report
Generation

Structural
Notes

Figure 1. Inspection and rating procedure.

Chapter 1 Introduction



Mode of Technology Transfer

It is recommended that the inspection procedures developed in this study for
tainter dam and lock gates be incorporated into Engineering Regulation (ER) 1110-
2-100, Periodic Inspection and Continuing Evaluation of Completed Civil Works
Structures.

Overview

The concepts in this report for the inspection and rating of tainter dam and lock
gates stem from work in similar projects for steel sheet pile structures (Greimann
and Stecker 1989, 1990), miter lock gates Greimann, Stecker, and Rens 1990),
sector gates (Greimann, Stecker, and Rens 1991), and tainter and butterfly valves
(Greimann, Stecker, and Veenstra, 1993). Basic ideas such as condition indexes,
safety and serviceability, quantification of distresses by field measurements,
limiting values of distresses, and others have been refined as the investigation of
new structures has broadened. Several enhancements and new ideas have been
developed and applied to tainter dam and lock gates.

The investigation by the ISU project team consisted of meetings, site visits, and
field investigations with Corps of Engineers personnel at several lock and power
dam facilities. At these meetings and site visits, Corps experts expressed their
opinions on the critical components and problems associated with the operation and
repair of tainter dam and lock gates. They suggested means of quantifying these
components and problems by relating them to the overall condition of the gates.
Using the experts’ comments, the project team formulated an inspection procedure
and a tentative set of rating rules.

Field Test

A field test consists of performing the inspection procedure at several lock and
dam facilities. The field test serves two purposes: First, to determine the plausibil-
ity of the inspection procedure, and second, to compare and calibrate the rating rule
results with the experts’ opinions to ensure that the current condition of a gate
would be reflected. A field test was conducted at several lock and dam facilities in
the St. Paul District. The ISU project team and Corps experts performed the
inspections. The problems encountered in the inspection procedure and the discrep-
ancies between the experts’ opinions and the results attained from the rating rules
were addressed.

Chapter 1 Introduction



The limiting value for section losses on the strut arms, main girders, and trunnion
girders is

Xue = 10% (3.43)

The ribs, upstream and downstream skin plates, and bracing have a limiting value
equal to 20 percent of the original volume:

Xia = 20 % (3.44)
The CI for corrosion is the minimum of the CIs from all the components.
CI = Minimum (ClypClypClypClpsClpClipClpClgClg) (3.45)

Example: A gate has a skin plate thickness of 3/8 in. From an inspection, the
average pit depth due to corrosion is recorded to be 1/8 in. on the upstream skin at
the splash zone, and it is estimated that approximately 10 percent of the one-square-
foot area is affected by the pitting. The percentage volume !nss is calculated from
Eq. (3.39).

_ 10 x 0.125 _

= 3.3%
0.375

UZ

The limiting value from Eq. (3.44) is
X,

maxUZ =

20%

The CI for the upstream skin at the splash zone is

Clyz, = 100(0.4)-” =

From Table 1, this CI is rated excellent.

Example: A gate has skin plate thickness of 3/8 in. From an inspection, the
average pit depth is recorded to be 1/8 in. on the downstream skin, the average
diameter is 2.0 in., and five pits are recorded on the one square foot section. From
Eq. (3.41)

Sxmx 2? x 0.125
4

Volume loss = = 1.96 in?

Chapter 3 Condition Index



* floating debris
* damaged gate.

Normal noises, jumping, and vibration are generally caused by seals or operating
machinery.

Measurement and limits

The presence of any noise, jumping, and vibration are recorded as the gate is
opened and closed through a 2-ft cycle. If any of the three occur, they are further
classified as normal or abnormal. Subjective judgement is required, in consultation
with the chief gate operator. Normal occurrences do not reduce the CI. The CI for
the possible combinations of abnormal noise, jumping, and vibration is shown

below:
Abnormal Noise, Jumping, or Vibration CL
None 100
Yes for one of the three 70
Yes for any two 40
Yes for all three 30

Obviously, this distress is more subjective than quantifiable; however, its impor-
tance should not be minimized. Abnormal jumping, for example, can indicate
structural problems.

Example: As a gate was lifted, it made a popping noise. Also, a squealing
noise due to the gate seals occurred throughout the gate operation. The CI is
CI = 70

because the popping noise is abnormal. From Table 1, this CI is rated very good. If
the popping noise had not occurred, the CI would have been 100 because the
squealing noise due to the seals is considered normal.

Chapter 3. Condition Index 35



ANCHORAGE MEASUREMENT: Measurements of relative movement between the
concrete pier and trunnion yoke or girder are taken in the downstream direction

(Figure 8). If the inspection is performed under NORMAL OPERATING
CONDITIONS, dial gauges are used to measure this movement and measurements are
taken with the gate in the closed and 2 ft. open positions and then again in the closed
position. For tracking relative movement over time, permanent reference points or
benchmarks are established on the trunnion girder and on the pier adjacent to the girder.
The distance between these points are recorded with the gate in the closed position after
the gate has been lifted and reset. A convenient means of doing this is by using a
trammel with permanently fixed trammel points for benchmarks. If BULKHEADED
CONDITIONS exist, dial gauge measurements are taken in the closed position with no
head on the gate and with full head on the gate. The term, no head, implies that the
water on the upstream face of the gate will be removed by opening the gate. If a
tailwater is present on the gate, the upper pool will be equal to the level of the lower
pool with no net head. To apply full head or load, lift the bulkhead and flood the gate.
Dial gauge measurements should be recorded to 0.001 inch. Trammel measurements
between the permanent reference points are taken in the no head condition. Trammel
measurements should be recorded as accurately as possible (about 0.0313 in. or 1/32

CONCRETE
PIER

in.).

Van GAUGE
TRUNNION
HUB

eo

TRAMMEL,

TRUNNION YOKE F|
“BENCHMARK
TRUNNION GIRDER af
—

Figure 8. Anchorage measurement.

Chapter 2 Field Inspection

23



40

Trammel measurements are used to measure long-term displacements and are
recorded in the closed position after the gate has been lifted and reset. This motion,
X,, is found by taking the difference between the maximum and minimum trammel
measurements (normal operating and bulkhead conditions) since the last repair. At
best, trammel measurements can probably be made with 1/32 in. accuracy.
Improved accuracy in this measurement is needed. Rigid anchorages have a
limiting long-term motion of

Xpar) = V8 in, (3.8)

The limiting motion for flexible anchorages is a function of L, the embedment
length.

Xx,

‘maxr(t) = 9.0025 (L) (3.9)

The CI for anchorage assembly deterioration will be the minimum of the Cls
calculated for the short- and long-term motion.

Cl = Minimum (ClsCI,) (3.10)

Example: Measurements of anchorage movement were made during an
inspection performed under normal operating conditions. The anchorage system
was flexible with an embedment length of 72 in. The maximum displacement
found using dial gauges was

X, = 0.005 in.

Trammel measurements indicate a displacement of

X, = 16 in.

occurred between this inspection and a bulkheaded inspection 10 years ago.
Cracked and spalled concrete was evident around the trunnion yoke. Also, the
casting bolts and nuts had a significant amount of corrosion. The limiting value of
short-term anchorage motion is found using Eq. (3.7).

Xnaxris) = 0.0001 (72) = 0.0072 in.

The limiting value of long-term anchorage motion over time is found using Eq.
(3.9).

Xx,

‘marry = 0.0025 (72) = 0.180 in.

Chapter 3 Condition Index



22

U.S. ARMY CORPS OF ENGINEERS PAGE 3
TAINTER DAM AND LOCK GATE STRUCTURE INSPECTION

OPENING AND CLOSING OF THE GATE

IS IT NORMAL?
NOISE? Y N Y N
JUMPING? Y N Y N
VIBRATION? Y N Y N

VIBRATION WITH FLOW,
GATE VIBRATION (LEVEL 0, 1, 2, 3, or 4):
CAN VIBRATION BE ELIMINATED BY GATE OPENING ADJUSTMENT? Y N

MISALIGNMENT
HOW WILL MEASUREMENTS BE TAKEN? (no.)__1. TAPE MEASURES
2, ELECTRONIC LEVEL
COMPLETE IF TAPE MEASURES ARE USED
CLOSED 2' OPEN CLOSED
LEFT EDGE (in.)
RIGHT EDGE (in.)

COMPLETE IF ELECTRONIC LEVEL IS USED
CLOSED 2' OPEN CLOSED
ANGLE (degrees)

ANCHORAGE ASSEMBLY DETERIORATION
LEFT SIDE RIGHT SIDE

CONCRETE CRACKED OR SPALLED? Y N Y N
BOLTS/NUTS: CORRODED? Y N Y N
LOOSE? Y N Y N
MISSING? Y N Y N

IS THE EMBEDDED ANCHORAGE FLEXIBLE OR RIGID? F R
IF FLEXIBLE, LENGTH OF EMBEDMENT (in.):

ANCHORAGE MEASUREMENT (Measurements are taken in the downstream
direction.)

COMPLETE IF NORMAL OPERATING CONDITIONS
LEFT SIDE (in.) RIGHT SIDE (in.)
CLOSED 2'OPEN CLOSED CLOSED 2'OPEN CLOSED
Dials
Trammels

COMPLETE IF BULKHEADED CONDITIONS
LEFT SIDE (in.) RIGHT SIDE (in.)
NO HEAD FULL HEAD NO HEAD FULL HEAD
Dials
Trammels

Chapter 2 Field Inspection


4 Field Testing

As summarized in Chapter 3, several site visits were conducted to establish the
condition index rules. To test the performance of the rating rules, a field test was
conducted to compare the calculated CI values based on those rules to the CI values
subjectively determined by several Corps engineers who are tainter dam and lock
gate experts. The experts involved in the initial rule development that took place at
Ice Harbor Lock and Dam in the Walla Walla District were Scott Sutliff (Walla
Walla District), Brian Schmidtke (Portland District), Ed Reynolds (Seattle District),
Al Hokanson (Walla Walla District), Marty Mendiola (Walla Walla District), Jim
Bluhm (Walla Walla District), and Tom Schmitz (Seattle District).

In July 1993, inspections were performed in the Little Rock District on gates at
David D. Terry Lock and Dam 6 and at Greers Ferry Dam and Powerhouse. The
experts who participated in the inspections and furthered the development of the
rating rules were Scot Sutliff, Brian Schmidtke, Bob Harris (Little Rock District),
and Jon Gartner (Omaha District). No calibration with expert judgments was
performed.

In November 1993, a field test was conducted in the St. Paul District. The
experts involved were Bob Harris, Brian Schmidtke, Gerald Cohen (St. Paul
District), Jim Bigham (Rock Island District), and Fred Joers (Rock Island District).
The field test was conducted at four different sites along the Mississippi River:
Lock and Dam 2, 4, and 5A, and Lower St. Anthony Falls. Two gates were in-
spected at each site. The gates at Lock and Dam 2, 4, and SA were all nonsub-
mersible tainter dam gates with rigid anchorages. Gate 1 at Lower St. Anthony
Falls was a submersible dam gate with a flexible anchorage. The inspections on
these gates were performed under normal operating conditions. The other gate
inspected at Lower St. Anthony Falls was a submersible auxiliary lock gate with a
unique flexible anchorage configuration (Figure 17). The inspection of this gate
was performed under bulkheaded conditions. The results of these field tests were
used to make minor modifications and one major modification (Eq. 3.53), and to
calibrate the rating system for tainter dam and lock gates. Each expert was asked to
assign a CI to the individual distresses for each gate investigated, based on their
expert judgment. The experts also were asked to rate the overall condition of each
gate. Their subjective ratings were compared to the CIs calculated from the rating
tules. This led to some adjustment of the X,,,, values and weighting values to better
fit the experts’ ratings. The previous portions of Chapter 3 include these changes.

Chapter 4 Field Testing 59



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, “Devel-
opment of Uniform Evaluation for Procedures/Condition Index for Deteriorated
Structures and Equipment,” for which Stuart D. 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; Dr. Anthony M. Kao was the Problem Area Leader for the Operations
Management problem area during this study. Mr. David T. McKay is the current
Problem Area Leader for the Operations Management problem area.

This study was performed by the Department of Civil and Construction Engi-
neering, Iowa State University, under contract to the U.S. Army Construction
Engineering Research Laboratories (USACERL). Principal Investigators for lowa
State University were Lowell Greimann, James Stecker, and Michael Nop. The
study was conducted under the general supervision of Dr. Paul A. Howdyshell,
Chief of the Engineering and Materials Division (FM), Infrastructure Laboratory
(FL), USACERL. The USACERL technical editor was Linda L. Wheatley, Techni-
cal Resources Center.

COL James T. Scott is Commander and Acting Director, USACERL, and Dr.
Michael J. O’Connor is Technical Director.

vi



Chapter 2 Field Inspection

This Page Intentionally Left Blank

13



50

The CI for all dents is the minimum of the Cls for the individual components:

Xn = 1 (3.35)
Xpaxp = 3 (3.36)
Xnaxe = 3 (3.37)
CI = Minimum (ClipClpyClClypClyyCly) (3.38)

Example: The only dent data observed were six dents on the upstream skin
plate of a tainter gate.

Xy = 6

The CI for upstream skin dents is

Cly = 100(0.4)" = 58

The CI for all dents is
CI = Minimum (58,100,100,100,100,100) = 58

The Cl is rated fair.

Corrosion/Erosion Distress

Definition and Causes

Corrosion involves the uniform loss of steel material on a gate structure because
of interaction with the environment. Pitting is a result of corrosion, caused by the
loss of steel section in localized areas. Erosion describes an accelerated rate of
deterioration caused by movement between water and metal. Varying rates of
degradation exist, depending upon the length of time the gate has been submersed,
the site-specific water conditions (chemistry and abrasive material content), the
environmental conditions of the air, and the normal amount of head on the structure.

Chapter 3 Condition Index



ously affect the structural integrity of the gate. In that case, the combined CI for the
gate is automatically reduced to 30.

CI = 30 (3.53)

Previous work done by the ISU project team has established that the relative
importance of a distress should be greater as the distress becomes more severe.
This concept is established by introducing a variable adjustment factor, which will
increase the distress weighting factor w, as its CI approaches Zone 3. The adjust-
ment factor plotted in Figure 16 has a maximum value of eight; that is, if a distress
has a CI that is less than 40, its importance increases eight times.

Chapter 3. Condition Index 57



30

U.S. ARMY CORPS OF ENGINEERS PAGE 6
TAINTER DAM AND LOCK GATE STRUCTURE INSPECTION

CRACKS RECORD COMPONENT, LENGTH, AND LOCATION
COMPONENT: US SKIN PLATE (U), DS SKIN PLATE (D), RIBS (R), MAIN
GIRDERS (M), BRACING (B), STRUT ARMS (S), TRUNNION HUB (H),
TRUNNION YOKE (Y), TRUNNION GIRDER (G)

COMPONENT LENGTH (in) LOCATION
(1):
(2):
(3):
(4):
6):

DENTS RECORD COMPONENT, HEIGHT, WIDTH, DEPTH, AND LOCATION
COMPONENT: US SKIN PLATE (U), DS SKIN PLATE (D) 2
COMPONENT HEIGHT(ft.) WIDTH(ft.) DEPTH(in.) LOCATION

(1):
(2):
(3):
(4):
(5):

RECORD COMPONENT, LENGTH OF DENT, OUT OF PLANE DISTANCE, AND
LOCATION. COMPONENT: RIBS (R), MAIN GIRDERS (M), BRACING (B),
STRUT ARMS (S)
COMPONENT LENGTHOF OUT OF PLANE LOCATION
DENT (in.) | DISTANCE(in.)

(1):
(2):
(3):
(4):
(5):

LEAKS RECORD TYPE, LENGTH, AND LOCATION
TYPE: BOTTOM (B), LEFT (L), RIGHT (R)

LOC'N(B,L,R) LENGTH (in) DISTANCE FROM TOP/LEFT(ft.)
(1):
(2):
(3):
(4):
(5):

SEAL CONDITION
HOW MANY (IF ANY) SEAL BOLTS ARE MISSING? __ RECORD LENGTH
AND LOCATION OF DAMAGED(D) AND MISSING(M) SECTIONS.
LOCATION: BOTTOM (B), LEFT (L), RIGHT (R)

COND'N(D,M) LOC'N(B,L,R) LENGTH(in.) DIST FROM TOP/LEFT(ft.)
(1):

(2):
(3):
(4):
(5):

Chapter 2. Field Inspection


70

Level 2 Flag: 40<CI<55

Note: The anchorage movement was measured to be X inches and could be
a problem. Further investigation may be needed.

Level 3 Flag: 0<CI<40

Note: The anchorage movement was measured to be X inches. This is
potentially a structural hazard. Further investigation is needed.

For all the component crack distresses (except main girder cracks) listed in the

structural distress subset, only a Level 3 Flag would apply because the Cl is
automatically 30 if such a crack exists.

Chapter 5 Structural Considerations



Page 6 Comments: Field Data
Completed at site inspection.

CRACKS: The presence of cracks on any component, especially the trunnion girder,
trunnion yoke, trunnion hub and strut arms should be recorded. The location and length
of upstream and downstream skin plate, rib, main girder, bracing, strut arm, trunnion
hub, trunnion yoke, and trunnion girder cracks are made with a ruler or tape measure.
The location of the crack on a component should be adequately described for evaluation
purposes and future comparisons.

DENTS: For upstream and downstream skin plates, the height, width, depth, and
location of dents are recorded using a ruler or tape measure. For rib, main girder,
bracing, and strut arm dents, the length, out of plane distance, and location of each dent
is recorded. Out of plane distance refers to the displacement of the member with respect
to its longitudinal axis.

LEAKS: Record the location of leaks as, bottom (B), left (L), or right side (R). Record
side leaks only if there is more than 2 ft. of head on the gate. Ignore leaks within 3 in.
of the corners. The length and location of each entry is also recorded. The length is
estimated and the location is in reference to the top or left side of the gate.

SEAL CONDITION: Record the number of seal bolts which are missing. Record any
damaged (D) or missing (M) sections of seal and record the location as, bottom (B), left
(L), or right side (R). A section of seal is considered damaged if it is cracked, ripped, or
improperly attached. Missing sections refer to complete sections broken off because of
debris, age, or other causes. Also, the length and location of each entry is recorded.
The length is measured with a ruler and the location is in reference to the top or left side
of the gate.

Chapter 2 Field inspection

31



46

measurements would have been taken under the no-head and full-head conditions
with the gate in the closed position.

Trammel measurements also are recorded under the no-head and full-head
conditions. These measurements are used with the normal operating trammel mea-
surements to determine the maximum and minimum values. First-time measurements
taken under the no-head condition probably will yield a critical reference distance.

Example: A first-time inspection was performed on a gate. It was found that
the lubrication system was leaking grease. From dial gauge measurements taken
under normal operating conditions, the following horizontal and vertical short-term
movements were calculated by taking the difference between the 2-ft open and the
closed readings.

Xypys) = 0.032 in.

rons) = 0.060 in.

Trammel measurements were also taken for the first time and, therefore, no
movements were calculated because no previous measurements between the
benchmarks existed. The total movement is found by Eq. (3.18):

Xrop = V.060)? + (0.032 ° = 0.068 in.

The CI for total movement is

Clyop = [100(0.4)°°%75}0.85 = 52

where the 0.85 factor was used because of problems with the lubrication system.
The lateral movement was estimated as 1/8 in.

Xyar = V8 in.

The CI for lateral movement is

Cliyr = (10000.4)""5®]0.85 = 63

Therefore, the final CI for trunnion assembly wear is the minimum of the individual
Cls

CI = Minimum (52,63) = 52

This Cl is rated fair.

Chapter 3 Condition Index


Page 3 Comments: Field data
Completed at site inspection.

OPENING AND CLOSING OF THE GATE: Observation of the gate during operation
is a good indicator of problems. Open the gate 2 ft. and record the occurrence of any
noise, jumping, or vibration of the gate. Observe the gate during closing also. If any of
the three exist indicate whether or not it is normal.

VIBRATION WITH FLOW: During opening of the gate to 2 ft., indicate the level of
gate vibration observed using the scale below.

Level Description of Vibration Level

0. No vibration
1 Feel with finger tips, hear humming noise, or water standing in gate
structure ripples
2 Large ripples (% in. high) on upper pool
3 Rattles grating, handrails, and bracing, etc.
4 Vibrates or shakes pier
If vibration exists determine whether or not it can be eliminated by adjusting the height
of the gate.

MISALIGNMENT: Measurements are recorded with the gate in the closed and 2 ft.
open positions and then again in the closed position. Measurements can be made by
attaching a tape measure to the skin plate on each side of the gate and recording the
distance from a fixed reference point above the gate to the top of the gate (Figure 7).
An alternative method of measurement consists of placing an electronic level
horizontally along the skin plate and recording the angles (in degrees) at each gate
position. (Levels should measure angles to the nearest 0.001 degrees.)

ANCHORAGE ASSEMBLY DETERIORATION: Indicate the presence of excessive
cracked or spalled concrete at the interface around the anchorage connections.
Excessive concrete spalling may indicate a displacement occurred at this location at
some time and may or may not show up in the current inspection. Small hairline
cracks, probably caused by thermal expansion or contraction of the concrete, should be
ignored in this analysis. Indicate whether the anchor or casting bolts and nuts are
significantly corroded. Significant corrosion refers to an approximate 10% volume
reduction. Indicate whether or not the anchor and casting nuts are tightened properly.
This is done with a torque wrench or by visual inspection for signs of movement
between the bolted components during operation. Indicate if there are any broken or
missing anchor or casting bolts and nuts. Some embedded anchorages are designed to
permit small movements. These types of anchorage configurations are called flexible
anchorage systems. Indicate if the embedded anchorage is rigid or flexible and if
flexible give the length of embedment in inches.

Chapter 2 Field Inspection 19



The Cl for all other cracks is 100. The individual distress CI for cracks using Eq.
(3.31) is

Cracks CI = Minimum (30,100,100,100,100,100,100,54,100) = 30

Because a crack is present in the strut arms, the combined CI for the gate is
automatically reduced to

Combined CI = 30

From Table 1, the crack CI and the combined CI are rated as poor; function is
seriously impaired.

Dents Distress
Definition and Causes

Dents represent a disfiguration of the major components of tainter gates. Dents
are typically caused by:

* vessel or barge impact
¢ debris impact
* operation with ice.

Dents could pose a safety problem, particularly if a badly deformed component
cannot safely carry its design load.

Measurement and Limits

The number of dents on the upstream skin plate (U), downstream skin plate (D),
strut arms (S), main girders (M), bracing (B), and ribs (R) will be recorded. Size
and location of dents also will be recorded, but are not used in the CI calculation.
The limiting values for these components are

Xa = 10 (3.32)
Xnap = 10 (3.33)
Xnas = 1 (3.34)

Chapter 3 Condition Index 49



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Chapter 3 Condition Index

58


Contents

List of Figures and Tables ..

Introduction
Background .
Objective
Mode of Technology Transfer
Overview

Field Inspection 0.00.0... 0. cece eee cece eet eee nen ener e eee e eens
Inspection Procedure Development
Overview of Inspection Procedure .
Overview of Inspection Form

Condition Index 0.0.0... cece cee cece nnn e een enn nen ees
Distress Descriptions and X,,,,
Noise, Jumping, and Vibration Distress .
Vibration With Flow Distress
Misalignment Distress
Anchorage Assembly Deterioration Distress .
Trunnion Assembly Wear Distress
Crack Distress
Dents Distress
Corrosion/Erosion Distress . .
Cable/Chain Plate Wear Distress
Leaks Distress ..........

Seal Condition Distress
Multiple Distresses ........ 6600-0 c eee e eee cece eee eee e eee eee

Field Testing
Noise, Jumping, and Vibration .
Vibration With Flow
Misalignment
Anchorage Assembly Deterioration



38

inhibit gate movement along the pier. The limiting value of the X measurement
(height differential between the two edges of the gate) is, therefore, a function of the
width and height, H, of the gate:

Xpax = (0.25 in.)(WIH) (3.5)

Example: A gate is 60 ft wide and 30 ft high. Measurements reveal that the
right edge of the gate rises 0.30 in. higher than the left side during the nominal 2-ft
opening. From Eq. (3.5),

Xnax = (0.25)(60/30) = 0.50 in.

The CI for misalignment is

CI = 100(0.4)°9 = 58

From Table 1, the CI for misalignment is described as being good.

Anchorage Assembly Deterioration Distress

Definition and Causes

Anchorage assembly deterioration represents the displacement of the embedded
anchorage system and the current condition of the assembly components, especially
the trunnion casting and anchorage bolts. Movement can occur during opening and
closing of a gate or, over time, because of sustained loading. There are several
causes of anchorage deterioration:

* corrosion

* concrete cracking and spalling

* anchor bolt elongation or movement
* loose or missing casting bolts

* additional load.

The anchorage system on either side of the pier or lockwall is the only mechanism
that connects a gate to the concrete support. Hence, the presence of anchorage
movement may indicate a significant structural problem, or it could eventually
introduce structural problems into other gate components. In addition, corroded,
loose, or missing casting and anchorage bolts and nuts can cause irregular
movement of the gate, introducing functional and structural problems into various
components. Corrosion of high strength steels, such as prestressing tendons, may
be particularly important.

Chapter 3 Condition Index


Vibration With Flow Distress
Definition and Causes

The vibration with flow distress represents the level of vibration present on a
gate opened 2 ft as water flows underneath it. The causes of this distress can be
attributed to:

* loose connections

* poor inflow conditions
* poor lip design

* trash or debris.

A gate subjected to vibration over an extended period of time could reduce the
structural integrity of the gate due to fatigue.

Measurement and Limits
The level of gate vibration is recorded on the inspectioi, form. The severity of

gate vibration and the corresponding CI are determined by comparing sensory
observations with the following descriptive levels:

CL Level Level Description
100 0 No vibration
90 1 Feel with finger tips, hear humming noise, or standing

water in strut arm ripples

70 2 Large ripples, approximately ¥ in. high, on upper pool
40 3 Rattles grating, handrails, and bracing, etc.
30 4 Vibrates or shakes pier

If vibration can be eliminated by lifting or lowering the gate, then the CI is raised to
the CI of the next lower level.

Example: The grating and handrails were rattling as water rushed underneath
the gate. The gate was raised another foot and the signs of vibration discontinued.
The CI for vibration with flow is CI = 70 because the Level 3 vibration could be
eliminated. Table 1 indicates the Cl is rated very good. If the vibration had
continued, the CI would have been 40.

Chapter 3 Condition Index


Noise, Jumping, and Vibration (Figure 18)

Because no abnormal noise, jumping, or vibration was recorded, the calculated
Cl values were 100. Although no abnormal distress information was recorded, the
experts did not give this distress a perfect rating. Normal vibration was observed on
Gate 2 at Lock and Dam (L&D) 2 and on Gate 10 at L&D 4; also, normal noise and
vibration were observed on Gate 9 at L&D 5A. The experts may have rated this
distress lower than 100, particularly on the gates where normal occurrences were
observed, because they did not feel that a distress CI should be 100 if the structure
was not new. This phenomena is consistent with what experts have felt about
previous structures. Gate 8 at L&D 4 has an expert average rating of 89, which is
unexplainably low because no normal or abnormal occurrences of this distress were
recorded.

100

90 N ry N N

N LL ry _| 7 NI N N]

e+ N

707) NI x KY

604 *

504 «

«04

nd Ki]

- :

104

° Gate 1 Gate 2 Gote 8 Gate 10 Gate 9 Gate 10 Gate 1 Lock Gate

Lock & DAM 2 Lock & DAM 4 LOCK & DAM SA LOV. ST. ANTHONY FALLS
Dex. avo (Mode Bexn. Hox exe. tn

Figure 18. Noise, jumping, and vibration.

Vibration With Flow (Figure 19)

Again the calculated CIs for each gate were 100 and the experts rated the gate
lower. Level 1 gate vibration was experienced on Gate 2 at L&D 2 and on Gate 9 at
L&D 5A, which explains the lower-than- normal expert average rating for these two
gates. However, the vibration disappeared when the position of the gates was
adjusted and, therefore, the calculated CI was 100.

Chapter 4 Field Testing



water to pass over them. Partially submersible dam gates can also be raised to allow
water to pass underneath.

Tainter Gate Component Identification

To inspect and rate tainter dam and lock gates requires familiarity with the
configurations and components of such structures. Definitions and sketches of
these components are presented in the following paragraphs:

Skin plate: An upstream skin plate is welded or riveted to the ribs to provide
stiffness to the structure (Figures 3, 4, and 5). It dams the water and transfers
load to the ribs. A downstream skin plate also may be present.

Ribs: The ribs, usually tees, are welded or riveted to the main girders. The ribs
transfer load from the skin plate to the main girders (Figures 3, 4, and 5).

Main girders: The main girders can be either horizontally or vertically posi-
tioned. They span the width or height of the gate and transfer load from the
skin plate and ribs to the strut arms (Figures 3, 4, and 5).

Strut arms: Strut arms are the steel girders that transfer load from the main
girders to the trunnion assembly (Figures 3, 4, and 6). Some strut arms are
parallel to the pier face and some slope toward the center of the gate from the
trunnion, as shown in the figures.

Trunnion assembly: The trunnion assembly consists of a trunnion hub with
bronze bushing and heavy flanges, a trunnion yoke, and a trunnion pin (Figure
6). The trunnion assembly transfers load from the strut arms to the trunnion
girder.

Trunnion hub: The trunnion hub consists of a cylindrical plate and bushing
which encompass the hinge pin and transmit load from the strut arms to the

trunnion yoke (Figure 6). The flanges align the strut.

Trunnion yoke: The trunnion yoke is bolted to the concrete or steel trunnion
girder (Figure 6). It transfers load from the trunnion hub to the trunnion girder.

Trunnion pin: The trunnion pin acts as the pivot point of the gate.
Trunnion girder: The concrete or steel trunnion girder is anchored into the

pier or lockwall (Figures 3 and 6). It transfers load from the trunnion yoke to
the pier or lockwall.

Chapter 1 Introduction



48

felt that, should a crack be present on any one of these components, the
individual CI for the crack distress should be reduced to 30.

Cly Cl Cl or Clg = 30 (3.29)

But, more importantly, the combined Cl for the entire gate should also be
reduced to 30.

Combined CI = 30 (3.30)
The experts judged that a crack in these critical items could result in the loss

of a gate and the upper pool. This could have serious consequences on navigation
or power generation. Some cracks in concrete may be due to shrinkage and should
not be recorded. The CI for all cracks is taken as the minimum of the CIs for all the
components.

CI = Minimum (ClClgClpClyClypClpClClypCly) (3.31)

Example: The following number of cracks were counted on a gate:

Since the strut arm is a critical member, the CI for strut arm cracks by Eq. (3.29) is
Cl, = 30

By Eq. (3.27), the limiting value is three cracks and the CI for upstream skin plate
cracks is

Cl, = 1000.48 = 54

Chapter 3. Condition index



54

Example: A 3/4-in. bearing plate has been worn 1/4 in. deep by the lifting
cable. The percent wear is
i

X= (100) = 33%

4

The CI for cable/chain plate wear is
CI = 100(0.4)" = 55

The Cl is rated good.

Leaks Distress

Definition and Causes

Leaks occur around the wetted perimeter of the gate. The two main causes of
leaks are:

* improper gate alignment
* seal damage.

Leaks are recorded because they are an indication of how well a gate performs its
primary function of holding back water.

Measurement and Limits

The length, height, and location of leaks are recorded on the inspection form.
Only the length of leaks is used in the calculation of the CI. The X value is the
percent of total length with seal distress (that is, the total length of all leaks) divided
by the length of the wetted perimeter multiplied by 100. If the gate is submersible,
the X value is the total length of all side leaks divided by the length of the wetted
side perimeter multiplied by 100. The limiting X,,,, is dependent upon the type of
gate and project. Tainter dam and lock gates used in a power plant application have
a limiting value of

Xpaxp = 2% (3.48)

Chapter 3 Condition Index



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tamer ;

Nes sem
}—v

Figure 6. Example trunnion assembly detail (individual projects differ

DOWNSTREAM

considerably).
Chapter 1 Introduction



Repair, Evaluation, Maintenance, and
Rehabilitation Research Program

REMR Management Systems—
Navigation Structures
Condition Rating Procedures
for Tainter Dam and Lock Gates

by Lowell Greimann, James Stecker, and Mike Nop
Engineering Research Institute

lowa State University
Ames, lowa 50011

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

Technical Report REMR-OM-17

September 1995



Page 5 Comments: Field Data
Completed at site inspection.

CORROSION: An area of one square foot of corrosion or erosion is selected on each
component. This area should characterize the maximum density of average depth
corrosion or erosion. For each component, indicate if corrosion (C) or erosion (E)
caused the material loss. Estimate or check drawings for the original section thickness
(SECT THICK) of each component. The maximum pitting depth (MAX. DEPTH) is
recorded in column 3. For the one square foot, the average pitting depth (AVG DEP-
TH) is also recorded. Deterioration can be measured in one of two ways. For the
selected area record either the percentage of the area (% AREA) which is pitted or count
the actual number of representative pits (NO. PITS). If the data was entered by
counting the number of pits, record the average diameter (AVG DIA) of the representa-
tive pits in the last column. In some cases, when the percentage area method is used
and the deterioration is uniform, the percentage of area affected could be 100% and the
average pitting depth is the average thickness reduction.

CABLE/CHAIN PLATE WEAR: Indicate if there is a bearing plate attached to the skin
plate for the cable or chain to bear upon. Estimate or check drawings for the original
section thickness of the bearing plate, if one exists, or the skin plate. Circle the proper
answer to indicate if wear is visible. If visible, estimate the maximum depth of wear
and circle the correct depth.

Chapter 2 Field Inspection

29


6 Summary and
Recommendations

The inspection and rating procedures described in this report have intentionally
been kept as simple as possible. The inspections require only simple tools such as a
tape measure, dial gauge, and ruler. An inspection form has been developed for
tainter gates to record historical information (location, previous inspections, repair
history, and so forth) and to document distress information (anchorage assembly
deterioration, cracking, corrosion, and so on).

The tools and the inspection procedures are relatively simple, but preparation
for an inspection is not always as simple. An inspection performed under bulk-
headed conditions requires setting the bulkhead(s) in place. There are distresses,
such as corrosion and trunnion assembly wear, that require several measurements.

Once the data is obtained, software has been developed to compute the CI
directly from the inspection records. The CI is a numbered scale from 0 to 100 that
indicates the current state of the structure. It is primarily a planning tool that
indicates the relative need to perform REMR work. CIs below 40 indicate that
immediate repair may be necessary or possibly that a more detailed inspection and
analysis is required.

Several distresses reduce the CI according to rules based on the opinion of
Corps experts. They involve at least two considerations: (1) serviceability, or how
the structure performs its function on a day-to-day basis, and (2) subjective safety,
or how, in the judgment of expert engineers, the safety of the structure has been
degraded by various distresses. A combined CI for each gate is calculated by
weighting each distress. Structural considerations are flagged on the CI list on the
basis of subjective safety. A structural note is generated on the summary report for
the structural subset of distresses as the CI decreases.

The inspection and rating procedure has been applied in one field test on eight
different gates (November 1993). The results of these tests have been incorporated
into the current version of the procedure. The current inspection and rating proce-
dure for tainter gate structures will undergo some modifications.

Chapter 5 Summary and Recommendations

71



Page 2 Comments: Historical or General Data
Completed prior to the site inspection and verified or changed during the site inspection.

Gates are sometimes replaced or removed during rehabilitation. It is important for later
reference to record the history of the gate which is currently in place.

Enter major MAINTENANCE, REPAIRS, OR OTHER MODIFICATIONS performed
on the gate within the last 10 years. A major repair is any repair which takes the gate
out of service.

Enter PREVIOUS INSPECTION information for reference purposes.

Record the CONDITION OF LIFTING EQUIPMENT and the overall CONDITION OF
GREASING SYSTEM.

Chapter 2 Field Inspection

17



The contents of this report are not to be used for advertising, publication,
or promotional purposes. Citation of trade names does not constitute an
official endorsement or approval of the use of such commercial products.
The findings of this report are not to be construed as an official
Department of the Army position, unless so designated by other authorized
documents.

DESTROY THIS REPORT WHEN IT IS NO LONGER NEEDED

DO NOT RETURN IT TO THE ORIGINATOR


The CI calculated for short-term anchorage movement is

Cl, = [100(0.4)°%5"972]9.79 = 37

where the 0.70 factor was used because the casting bolts and nuts had significant
corrosion. The CI for long-term anchorage assembly motion is

CI, = [100(0.4)°%518}9,79 = 51

Therefore, the CI for anchorage assembly deterioration is

CI = Minimum (37,51) = 37

From Table | the Cl is rated poor; that is, there is serious deterioration of the
anchorage.

Bulkheaded conditions: Dial gauges are used to measure short-term movement
under bulkheaded conditions. This displacement, Xg, is the difference between the
full-head and no-head readings. The limiting value is dependent upon the percent
of head present on the gate, %H, which is equal to the head applied to the gate when
the bulkhead is removed, expressed as a percent of gate height, H (Figures 14 and
15). For a rigid anchorage, the limiting values are, if there is less than 20 percent
head on the gate,

Xpasns) = 0.005 in, (3.11)

Chy = HD
m = 4 con

UPPER POOL
ELEVATION
Z

Hy q LOWER POOL
ELEVATION
Z

ELEVATION
OF itt Hy

SPILLWAY

Figure 14. Percent head with tailwater.

Chapter 3 Condition Index

41



Page 4 Comments: Field data
Completed at site inspection.

TRUNNION ASSEMBLY WEAR: Indicate whether the lubrication system is
functional. If a unique situation exists, such as a nonlubricated trunnion, NA can be
circled. The horizontal and vertical measurements are used to detect motion between
the trunnion pin and the bushing. Indicate whether feeler or dial gauges will be used to
take the horizontal and vertical measurements. For some gate designs the trunnion pin
is exposed and, therefore, it may be possible and simpler to take the horizontal and
vertical gap measurements using feeler gauges. Trammel measurements are required.

For an inspection performed under NORMAL OPERATING CONDITIONS the
horizontal and vertical measurements are made with the gate in the closed and 2 ft. open
positions and then again in the closed position. If dial gauges are used to measure the
horizontal and vertical movement, it is important that the bearing surface for the dial
gauge stem be smooth, with no unevenness, since the trunnion hub rotates. If feeler
gauges are used, gap measurements are taken between the pin and bushing in four
locations: upstream, downstream, top, and bottom. Horizontal trammel measurements
are taken between permanent reference points or benchmarks which have been
established in convenient positions on the trunnion hub and yoke. Trammel
measurements are recorded in the closed position after the gate has been lifted and reset.
Estimate lateral movements and circle correct answer. Gouging occurs when the
trunnion hub bears on the trunnion yoke.

Under BULKHEADED CONDITIONS the measurements will be recorded with the
gate in the closed position when no head or load is present on the gate and when full
head exists. If feeler gauges are used, gap measurements shall be taken between the pin
and bushing in the same locations as under NORMAL OPERATING CONDITIONS. If
dial gauges are used, no special precautions are required to ensure a smooth bearing
surface for the stem because the trunnion hub will not rotate. Horizontal trammel
measurements are also taken between the permanent reference points for the no head
condition.

Chapter 2 Field Inspection

25


34

Distress Descriptions and X,,,,

If a tainter gate structure is designed and constructed properly, it has an initial
Cl of 100. Over time the structure will be exposed to varying environmental and
operational situations that will lead to the deterioration of its condition. As a result
of this continuing process the CI will be reduced. Eleven distresses for tainter lock
and dam gates, the first 10 of which affect the combined CI, have been identified for
categorization in this project. Each is identified and described briefly in Table 3.

In the following sections, potential causes of each distress are listed and
discussed. Diagnosing causes for each distress is a complex issue. Many times a
distress may have several possible causes, and often a combination of distresses
must be present before a certain cause can be identified. The sections describe the
measurement of X and limiting X,,,, Values for each distress. Examples also have
been provided to show how the measurements of X and limiting values are used to
produce a CI for each distress.

Noise, Jumping, and Vibration Distress

Definition and causes
Noise, jumping, and vibration represent tainter gate sounds and motions during
opening and closing of the gate. Abnormal noise, jumping, and vibration can be

caused by several factors:

* improper lubrication
¢ misalignment of gate

Table 3. Tainter dam and lock gate distresses,

Distress Description
Noise/ump/vibration ‘Abnormal noise, jumping, or vibration during gate operation
Vibration with flow Vibration of gate as water flows underneath
Misalignment Twisting of gate between piers or lockwalls during lifting
Anchorage assembly Movement of embedded anchorage system and damaged components
deterioration

Trunnion assembly wear | Displacement between pin and bushing

Cracking Breaks in structural steel components
Dents Disfiguration of the steel components
Corrosion/erosion Loss of steel due to interaction with the environment

Cable/chain plate wear Wear on the skin or bearing plate due to sliding action of cable or chain

Leaks Water passing around the gate

Seal condition Condition of seals

Chapter 3 Condition Index


20

FIXED REFERENCE POINT +

PIER

+— TAPE MEASURE

SKIN PLATE

PIER

Figure 7. Misalignment measurement.

Chapter 2 Field Inspection



Condition Index

A condition index (CI) is the numerical measure used to rate the current state of
agate. The CI has two purposes: First, the CI values serve as a planning tool meant
to focus management attention on those tainter dam and lock gates most likely to
warrant immediate repair or further evaluation. Second, the CI values can be used
to monitor change in general condition over time and can serve as an approximate
comparison of the condition of different structures. One of the goals of this project
was to define a CI that uniformly and consistently ranks the condition of structures.

The REMR Cl 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 deterio-
rating characteristics of the structure. For management purposes, the CI scale is also
calibrated to group structures into three basic categories or zones (Table 1).

Tainter Gate Description

Tainter dam gates are used at the top of a dam to control the upper pool eleva-
tion, and tainter lock gates operate as upper gates in a lock chamber (Figure 2).
Although the function of tainter dam gates and lock gates are somewhat different,
their structural components are comparable. Their basic purpose is to hold back and
to pass water. Tainter lock gates are submersible; i.e., they are lowered below the
sill to allow vessels to pass over them during locking. Some dam gates are partially
submersible; i.e., they do not rest on a sill when closed and can be lowered to allow

Table 1. Condition index scale and zones.

Zone Condition Index Condition Description Recommended Action
Excellent: No noticeable defects. Some
85 to 100 aging or wear may be visible.
1 Immediate action is not required.
Good: Only minor deterioration or defects
70 to 84 are evident.
Fair: Some deterioration or defects are
55 to 69 heal but function is not significantly Economic analysis of repair
2 ~ alternatives is recommended to
vale inrati determine appropriate action.
4010 54 Marginal: Moderate deterioration.

Function is still adequate.

Poor: Serious deterioration in at least
25 to 39 ‘some portions of the structure. Function
is inadequate.

Detailed evaluation is required to
Very Poor: Extensive deterioration. determine the need for repair,
Barely functional. rehabilitation or reconstruction.
Safety evaluation recommended.

3 10 to 24

Failed: No longer functions. General
Otod failure or complete failure of a major
‘structural component.

Chapter 1 Introduction



56

Multiple Distresses

The CI for each distress contributes to the combined CI for a gate. However,
some distresses reflect the condition of the gate more than others. To account for
this, weighting factors, w,, are assigned to each distress. Relative initial weights are
listed in Table 4. They reflect to some degree the opinions of the Corps experts and
the opinions of the authors. The normalized weighting factors, W,, are defined by

(3.51)
where
x W, = 100
These normalized values are also listed in Table 4. The combined CI for all
distresses is given by
CI = (W,CI, + W,Cl, + .... W,CI,V/100 (3.52)

where n represents the total number of distresses. (Note: If the cable/chain plate is
not visible and no CI was calculated, it is omitted from Eq. 3.51 and 3.52.)

Equation (3.52) is always valid unless a crack is detected in the strut arms,

trunnion girder, trunnion hub, or trunnion yoke (see section entitled Crack Distress).
The experts have judged that a crack in any one of these components could seri-

Table 5. Unadjusted weighting factors for tainter gate distresses.

Distress Ww Ww,

Noise, jump, and vibration 5.5 10.6
Vibration with flow 5.8 11.2
Misalignment Al 8.0
Anchorage assembly deterioration 10.0 19.3
Trunnion assembly wear 8.5, 16.4
Cracks 5.9 11.3
Dents 0.8 16
Corrosion/Erosion 6.8 13.2
Cable/Chain plate wear 3.0 5.8
Leaks 1.3 2.6
{f cable/chain plate wear is not measurable, the w, must be recalculated based on the w, of the other
nine distresses.

Chapter 3 Condition Index



72

References

Greimann, L., and J. Stecker, User’s Manual: Inspection and Rating of Steel Sheet
Pile Structures, Technical Report REMR-OM-3 (U.S. Army Corps of Engi-
neers, Washington, D.C., 1989).

Greimann, L., and J. Stecker, Maintenance and Repair of Steel Sheet Pile Struc-
tures, Technical Report REMR-OM-9 (U.S. Army Corps of Engineers, Wash-
ington, D.C., 1990).

Greimann, L. Stecker, J., and K. Rens, Management System for Miter Lock Gates,
Technical Report REMR-OM-08 (U.S. Army Corps of Engineers, Washington,
D.C., 1990).

Greimann, L., Stecker, J., Rens, K., and J. Veenstra, Inspection and Rating of Sector
Gates (Submitted to the U.S. Army Corps of Engineers, 1991).

Greimann, L., Stecker, J., and J. Veenstra, Condition and Rating Procedures for
Tainter and Butterfly Valves, Technical Report REMR-OM-14 (U.S. Army
Corps of Engineers, Washington, D.C., 1993).

Greimann, L., Stecker, J., Rens, K., and M. Nop, REMR Management Systems -
Navigation Structures, User’s Manual for Inspection and Rating Software,
Version 2.0, Technical Report REMR-OM-114 (U.S. Army Corps of Engineers,
Washington, D.C., 1994).

References



42

wy = fe
un = 7 100)

UPPER POOL
ELEVATION
va
H
Hy
ELEVATION
OF SILL LOWER POOL
Z ELEVATION

SPILLWAY

Figure 15. Percent head without tailwater.

For 20 to 50 percent head, X,,,, is a linear function of head.

(0.030 - 0.005 )
xX = (0.005 ) + ——————“(% H - 20%
macs) ~ ( ) (50% - 20% ) ( ) (3.12)
If the head exceeds 50 percent, then

Xnaxnts) = 0.030 in. (3.13)

Limiting values for flexible anchorage systems are defined in the following three
equations. If there is less than 20 percent head on the gate,

Xyaxs) = 0.0001 (L) (3.14)

For 20 to 50 percent head,

[0.0006(Z) - 0,0001(Z)] (oH ~ 20%) (3.15)

X eng = 0.0001 (L)
mak) oO (50% - 20%)

If head is greater than 50 percent, then
Xnaxrs) = 9.0006 (L) (3.16)

As in normal operating conditions, trammel measurements are used to monitor
anchorage motion over time. A minimum extension will probably be recorded

Chapter 3. Condition Index


Trunnion Assembly Wear Distress

Definition and Causes

Trunnion assembly wear refers to the total relative movement of the trunnion
pin or hub with respect to the bushing or trunnion yoke. This movement takes place
while the gate rotates through its normal range of motion and, over time, because of
sustained loading. Trunnion assembly wear can occur between the trunnion pin and
the bushing or laterally between the hub and trunnion yoke. It can be caused by
several factors:

* improper lubrication

* improper gate alignment

* opening and closing motion
* jumping and vibration.

Measurement and Limits

The condition of the lubricating system is recorded on the inspection form. If
the lubrication system is not functioning properly, it may not be critical, but over a
long period of time it can cause accelerated wear in the trunnion assembly.
Therefore, a reduction factor of 0.85 is used if lubrication is inadequate.
Measurements of relative movement are made in the horizontal, vertical, and
lateral directions. As with anchorage assembly deterioration, trunnion
assembly wear measurements can be made under normal operating conditions
or bulkheaded conditions. The lateral measurement, X,47, is estimated using a
ruler (Figure 12). The limiting value for lateral motion is the same regardless
of the conditions under which the inspection is performed.

Xnawar = 3/8 in. (3.17)

The measurements taken in the horizontal, Xyjog, and vertical, Xycp »
directions can be made using feeler or dial gauges and trammels (Figures 9,
10, 11). The total motion, no matter what measuring device is used, is
calculated by taking the square root of the sum of the squares of the horizontal
and vertical movements in each direction:

Xror = {non + Xen) (3.18)

Chapter 3 Condition Index


Chapter 1

SKIN

PLATE |

LIFTING
BRACKET

MA\

SPILLWAY

<HORIZONTAL)

LIFTING
MECHANISM

RIBS
STIFFENER PLATES

TRUNNION

GIRDER
STRUT

BRACING

IN GIRDER

<— PIER ———>

A,

Ay

Figure 3. Side view of tainter gate.

RIBS

MAIN GIRDER
CHORIZONTALY

DIAGONAL
BRACING

STRUT
‘ARM

- a)

as

UPSTREAM HALF
ELEVATION

LIFTING

BRACKET €

DOWNSTREAM HALF

ELEVATION

Figure 4. Elevation view of tainter gate.

Introduction