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NIST Internal Report 6660

Workshop on Quantitative Tools for Condition

Assessment of Aging Infrastructure

May 4-5, 2010

Boulder, Colorado

Editors:

Jessica Terry 

Tom Siewert

David McColskey

Ward Johnson

Materials Reliability Division

Materials Science and Engineering Laboratory 

William Luecke 

Mark Iadicola 

Dat Duthinh 

Metallurgy Division

Materials Science and Engineering Laboratory 

October 2010

U. S. Department of Commerce

Gary Locke, Secretary

National Institute of Standards and Technology

Patrick D. Gallagher, Director
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Table of Contents

Executive Summary ....................................................................................................................................... 4

Acronyms....................................................................................................................................................... 5

Introduction................................................................................................................................................... 6

Keynote Presentations .................................................................................................................................. 9

Breakout Sessions........................................................................................................................................ 10

I. Uncertainty in Inspection Data............................................................................................................. 10

A. Introduction..................................................................................................................................... 10

B. Presentations................................................................................................................................... 11

C. Discussion ........................................................................................................................................ 12

II. Advanced Sensors................................................................................................................................ 14

A. Introduction..................................................................................................................................... 14

B. Presentations................................................................................................................................... 14

C. Discussion ........................................................................................................................................ 15

III. Behavior of Connections..................................................................................................................... 18

A. Introduction..................................................................................................................................... 18

B. Presentations................................................................................................................................... 18

C. Discussion ........................................................................................................................................ 18

IV. Mechanical Response of Materials .................................................................................................... 20

A. Introduction..................................................................................................................................... 20

B. Presentations................................................................................................................................... 21

C. Discussion ........................................................................................................................................ 21

Bibliography................................................................................................................................................. 23

Appendix I – Presentations.......................................................................................................................... 25

I. Keynote Presentations.......................................................................................................................... 25
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II. Breakout session Presentations .......................................................................................................... 25

III. Supplemental Information ................................................................................................................. 25

Appendix II – Agenda................................................................................................................................... 26

Appendix III – Topic Rankings...................................................................................................................... 29

Appendix IV a – Stakeholders...................................................................................................................... 31

Appendix IV b – NIST Participants ............................................................................................................... 32
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Executive Summary

The Quantitative Tools for Condition Assessment of Aging Infrastructure workshop was held May 4-5, 

2010, to prioritize measurement and standards needs relative to inspection, maintenance, repair, and 

replacement of the Nation’s physical infrastructure. The workshop focused on steel bridges, and the 

principal stakeholders in attendance included bridge owners, manufacturers of inspection equipment, 

and government and academic researchers. Discussion themes included (1) uncertainty in inspection 

data, (2) advanced sensors, (3) behavior of connections, and (4) mechanical response of materials. 

Many measurement and standards needs were raised and discussed during breakout discussions, from 

which forty-three suggested research topics were deemed to be of high enough interest to be 

considered by the entire workshop. Twenty-three topics were selected and ranked by stakeholder vote 

to be of highest priority to the bridge community. The top eleven topics were: 

Methods for accurate, cost-effective field measurement of absolute stress or strain and any 

neccessary reference artifacts.

Simple and robust methods for rapid load rating of bridges.

Analysis and validation of existing and new crack arrest strategies, especially for distortioninduced cracks.

Methods to determine the location, size, and condition of reinforcing steel in hardened 

concrete. 

Standardized methods for accelerated life-testing of embedded sensors for structural health 

monitoring.

Standard reference specimens and calibration services to validate nondestructive inspection 

techniques and instruments.

Improved documentary standards for visual inspection methods and probability of detection.

Standard test apparatus for qualification of new sensors and instrumentation for structural 

health monitoring.

Critical data on the behavior of high performance steels and connections at high temperatures 

(400 :C to 1100 :C).

Validation of reduced-scale testing approaches to supplement full-scale testing.

Critical data on the fatigue resistance of bolted and riveted connections, especially when loose 

or exposed to high temperatures.

More details on these and other suggested topics can be found in the following report. This information 

will be used by NIST for internal program planning and will form the basis for development of new 

collaborations across organizations to address tasks of mutual interest.
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Acronyms

AASHTO American Association of State Highway and Transportation Officials 

ABC accelerated bridge construction 

AE acoustic emission 

ASR alkali-silica reaction 

BFRL NIST Building and Fire Research Laboratory, after Fiscal Year 2010 referred to as the 

NIST Engineering Laboratory

BMS bridge management systems 

DOT Department of Transportation 

EMAT electromagnetic-acoustic transducers

FEA finite-element analysis 

FEM finite-element model 

FHWA Federal Highway Administration 

GPR ground penetrating radar

HPS high-performance steels

LRFD load and resistance factor design 

MEMS micro-electro-mechanical systems 

MSE mechanically stabilized earth 

MSEL NIST Materials Science and Engineering Laboratory, after Fiscal Year 2010 referred to as 

the NIST Materials Measurement Laboratory

NBIS National Bridge Inspection Standards 

NCHRP National Cooperative Highway Research Program

NDE nondestructive evaluation

NIST National Institute of Standards and Technology 

PAUT phased-array ultrasonic testing 

POD probability of detection 

SHM structural health monitoring 

TIP NIST Technology Innovation Program

TRB Transportation Research Board 

UT ultrasonic technology
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Introduction

Recent high-visibility failures of aging structures in the US infrastructure have highlighted the need for 

improved technology and measurement science to better predict the remaining life of other critical 

structures. 1, 2Since limited funds are available for repair and replacement, the Nation must carefully 

prioritize these activities. These critical issues led to the organization of this workshop, which was 

focused on measurement needs for condition assessment of bridges.

The workshop, “Quantitative Tools for Condition Assessment of Aging Infrastructure,” was held May 4-5, 

2010, at the NIST laboratory in Boulder, Colorado. The goal of the workshop was to sharpen the focus of 

NIST’s programs by matching the measurement technology capabilities of MSEL, in conjunction with 

other NIST organizations (Building and Fire Research Laboratory and the Technology Innovation 

Program), with existing technology gaps in the bridge industry, specifically for assessing the condition of 

bridges to prioritize their repair and replacement. The workshop brought together 30 bridge 

stakeholders representing four categories: bridge owners, manufacturers of inspection equipment, and 

government researchers, and academic researchers. The stakeholders identified areas that prioritize 

measurement and standards needs relative to inspection, maintenance, repair, and replacement of the 

Nation’s physical infrastructure. The workshop began with several keynote presentations to frame the 

topics. After the keynote presentations, the participants developed and ranked a list of potential 

research activities in breakout sessions that focused on four subject areas: (1) uncertainty in inspection 

data, (2) advanced sensors, (3) behavior of connections, and (4) mechanical response of materials. The 

workshop concluded with all the stakeholders reconvening to develop a consensus on the most critical 

technologies. The agenda is included as Appendix II.

The stakeholders in attendance were leaders in the field or their chosen delegates, and were drawn 

primarily from contacts developed by NIST researchers at past bridge events such as the American 

Association of State Highway and Transportation Officials (AASHTO) July 2009 meeting, the 

Transportation Research Board's (TRB) January 2010 meeting, and visits to various universities. The NIST 

workshop provided a unique venue for comparison of NIST mission and MSEL’s expertise with critical 

research topics identified by these stakeholders. These proceedings document the discussed topics 

without comment and constitute no specific commitment by MSEL or NIST to pursue research in these 

areas. Technical conclusions of the workshop were also highlighted in a presentation on research needs 

at the AASHTO Subcommittee on Bridges and Structures Annual Meeting, May 23-27 in Sacramento, 

California [Friedland 2010].

The four breakout sessions were led by researchers with experience in the specific subject areas. For 

 

1

http://www.infrastructurereportcard.org/

2

http://www.ntsb.gov/dockets/Highway/HWY07MH024/404995.pdf
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each session, a NIST representative recorded the discussions and provided some guidance on whether 

the ideas would fit within the NIST mission. A brief background for each breakout session is presented 

below, and the results of the ensuing discussions are presented later in this report. Discussion of some 

pertinent current research is also included. 

1. Uncertainty in Inspection Data – Session chair: George Hearn, Session recorder: Jessica Terry

Goal: Reduce the uncertainty in the data developed during inspections and periodic NDE 

investigations

Background – Bridge inspection is a predominantly subjective undertaking, and relies heavily on 

inspector training and experience, as well as agency preferences. The National Bridge 

Inspection Standards (NBIS) stipulate maximum intervals for routine, underwater inspections as 

well as inspections of fracture-critical bridges. Routine and underwater inspections intervals are 

influenced by agency preferences for frequency as well as extensions subject to FHWA approval. 

Inspection and repair costs could be optimized if a bridge’s remaining life could be quantified 

through specific testing, tools, and measurement technology. This topic is currently under 

investigation with FHWA’s NCHRP Project 12-82, “Developing Reliability-Based Bridge Inspection 

Practices.” The project’s goal is to match the inspection cycle with the need for inspection, not 

just the calendar. Development of tools for in-depth and special inspections that locate damage 

that is undetected during visual inspections may be limited to certain classes of bridges. These 

classes of bridges may be the type where expensive replacement motivates maximizing the 

bridge’s life span. NDE tools have been developed to assist in bridge monitoring, but in many 

cases their application has been limited by complexity, availability, cost, and lack of guidance on 

field deployment. Certain methods can provide false readings (both positive and negative) due 

to improper calibration. An opportunity exists to expand the use of these advanced tools if their 

error and uncertainty could be reduced and their output could be simplified. 

2. Advanced Sensors – Session chair: Steven Lovejoy; Session recorder: Ward Johnson

Goal: Development and certification of practical SHM sensors

Background - Continuous SHM of bridges with permanently mounted sensors is now widely 

viewed as offering the potential of characterizing structural degradation in a more objective, 

complete, and timely manner than the periodic inspections that are currently employed. 

Although some new bridges are instrumented for SHM, approaches for sensor design and 

function are not well established. Methods of network integration and information processing 

are also not standardized.

3. Behavior of Connections – Session chair: Karl Frank; Session recorder: William Luecke

Goal: Improved prediction of actual performance of steel bridges through a better 

understanding of the behavior of connections

Background - The actual performance and safety of structural connections designed by use of 

simple empirical formulas are difficult to assess in the presence of initial imperfections in 

geometry or materials. Further scrutiny is needed, especially in the case of structures without 
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redundancies in the load path. Finite-element modeling (FEM) is a powerful tool to design a 

single connection or (through simplifications) an entire structure. Currently, however, it is too 

computationally complex to model an entire structure down to the level of a rivet, bolt, or weld, 

but it is in these details that the performance and critical failure conditions of the connections 

lie. Further refinement of models by adding fatigue, corrosion, realistic failure criteria, and the 

effects of fire for the materials at these critical links is also not routinely possible. To address 

these deficiencies, measurement of bridge connection degradation mechanisms and the 

resulting effect on performance is necessary. These measurements and observations must then 

be converted into simple but accurate numerical models that capture the current state of the 

overall system. Once established, these models could provide the necessary foundation for 

more accurately determining system safety during operation and could aid in establishing 

guidelines for sensor specifications and placement strategies for improved bridge inspection. 

Current collaboration with FHWA is shown in the recent output from NCHRP Project 12-84 

“Gusset Plate Connections for Steel Bridges” *Hartman 2010+.

4. Mechanical Response of Materials – Session chair: Theodore Zoli; Session recorder: Dat Duthinh

Goal: Quantify effects of environmental degradation, normal service loading, occasional 

accidental loading, design errors and extreme events such as fire or impact, on failure potential

Background - Structural engineers design for expected service conditions by use of well 

established, validated design rules backed by decades of experience, and for accidental loading 

by use of a limited probabilistic method- load and resistance factor design (LRFD)-. However, the 

in-service performance of structural materials under extreme conditions caused by fire, 

explosion, impact, and natural disasters, especially in aged, degraded conditions typical of the 

US infrastructure, is not well addressed in the design codes. Possible exceptions are in the 

structural response to hurricane and earthquake loadings and structural responses, which have 

attracted significant research funding for many years. Design errors may also cause dangerous 

conditions under normal service loads. Furthermore, next-generation materials intended as 

replacements may respond in unexpected ways, or their mechanical properties may not have 

been fully explored. In addition, most structural models assume average material properties 

(e.g., tensile strength of steel) based on data acquired at ambient temperatures under 

specifically defined load conditions – in fact, fire is not a design consideration for bridges at all! 

Accurate estimation of the residual factor of safety for aged structures under normal and 

“extreme” conditions is critical to prioritizing the need for repair or replacement. 

The breakout sessions started with additional presentations by stakeholders, followed by development 

of a list of potential research topics for NIST. The breakout sessions lasted two hours in the afternoon of 

the first day and another hour in the morning of the second day, which allowed the stakeholders to 

discuss potential research topics and their fit to the NIST mission and capabilities.

The top five to seven ideas from each breakout session were brought back to a plenary session. Here, 

the stakeholders heard explanations of all the ideas, and voted on their importance. The votes of each 

of the four categories of participants (bridge owners, manufacturers of inspection equipment, and 
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government and academic researchers) were kept separate to identify any group preferences. Based on 

the final vote in the plenary session, recommendations for the eleven highest priority areas of research 

include: 

Methods for accurate, cost-effective field measurement of absolute stress or strain and any 

neccessary reference artifacts.

Simple and robust methods for rapid load rating of bridges.

Analysis and validation of existing and new crack arrest strategies, especially for distortioninduced cracks.

Methods to determine the location, size, and condition of reinforcing steel in hardened 

concrete. 

Standardized methods for accelerated life-testing of embedded sensors for structural health 

monitoring.

Standard reference specimens and calibration services to validate nondestructive inspection 

techniques and instruments.

Improved documentary standards for visual inspection methods and probability of detection.

Standard test apparatus for qualification of new sensors and instrumentation for structural 

health monitoring.

Critical data on the behavior of high performance steels and connections at high temperatures 

(400 :C to 1100 :C).

Validation of reduced-scale testing approaches to supplement full-scale testing.

Critical data on the fatigue resistance of bolted and riveted connections, especially when loose 

or exposed to high temperatures.

Details on the voting breakdown are tabulated in Appendix III.

While this research list will help NIST determine the direction of research projects, the magnitude of the 

tasks is too great for NIST to complete by itself in a timely fashion. Collaborators and partners will be 

necessary to leverage NIST efforts.

Keynote Presentations

Five keynote presentations were given as broad overviews that would provide general guidance and 

background to the four breakout sessions3:

1. Frank Gayle (Metallurgy Division Chief, NIST), NIST Overview: Organization and Mission

This presentation described the structure of NIST, its mission, and the mission of MSEL.

 

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The slides from the keynote and breakout session presentations can be found in Appendix I
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2. Stephanie Hooker (Materials Reliability Division Chief, NIST), Overview of MSEL Plan: 

Quantitative Tools for Condition Assessment of Aging Infrastructure

This presentation described MSEL’s proposed plan to address the measurement needs in our aging 

infrastructure.

3. Ian Friedland (Technical Director, Bridges and Structures R&D, FHWA), Bridge Research: Current 

Issues and Future Opportunities

This presentation summarized the mission and capabilities of the FHWA and suggested how NIST could 

help to address critical research needs in highway infrastructure.

4. Dan Frangopol (Fazlur R. Khan Endowed Chair of Structural Engineering and Architecture, Lehigh 

University), Assessing and Predicting the Performance of Bridges to Prioritize their Repair and 

Replacement: Accomplishments and Challenges

This presentation was an academic perspective on the multi-faceted incorporation of reliability and 

optimization of bridge performance assessment, with comments on remaining challenges.

5. Alex Wilson (Customer Service Technical Manager, ArcelorMittal), American Iron and Steel 

Institute (AISI) Bridge Task Force, Overview and measurement needs that MSEL might fill

This presentation was a material supplier’s perspective of the research needs in infrastructure.

Breakout Sessions

I. Uncertainty in Inspection Data 

A. Introduction

The majority of topics discussed in the Uncertainty in Inspection Information breakout session fell within 

three categories: accessibility, validation, and evaluation. 

Accessibility refers to the need to effectively inspect (determine condition or behavior of) bridge 

elements that cannot be visually inspected. Non-visible elements include concrete reinforcing steel bars, 

prestressing strands (post-tensioned and pre-tensioned), some underwater foundation elements, steel 

pins, multiple plies of built-up material, joints in pre-fabricated structures, certain box girders, rock 

bolts, and steel straps embedded in mechanically stabilized earth (MSE) walls. Because inspections are 

performed primarily with visual techniques, many of the discussions related to the accessibility of 

various bridge elements could apply and overlap with the Advanced Sensor discussion.

The stakeholders identified a need for reference specimens that enable third-party validation of 

inspection technologies and technicians. This would enable greater confidence and justification for the 

use of existing NDE techniques that service industries provide. Again, many of these topics could have 

equally applied to the Advanced Sensors breakout session, but were raised here due to the desire for 

accurate conclusions from data obtained during inspections or periodic NDE investigations.

Evaluation combines needs in data mining and bridge management systems (BMS). Many state DOTs 

already perform element-level inspections, but methods for using data from these inspections are in 

need of refinement. First, routine visual inspections report obvious problems, but guidance in 
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determining responses to problems is needed. For example, is a reported problem critical? Is the 

problem in a critical member? Has the growth of a crack relieved the stresses that produced it? Second, 

upon discovery of a problem in one bridge, what are the criteria for determining how comparable 

bridges with potentially similar problems should be investigated, and with what priority?

B. Presentations

Mike Loeffler (Bridge Operations and Maintenance, Ohio DOT) highlighted problems in determining the 

condition and the remaining load capacity of steel bridge pins. Determining whether the pins have 

frozen and should be considered fixed or whether they are they truly behaving as pins, are questions 

that sometimes remain unanswered. The limited capacity that results from corroded pins is illustrated 

by a particular bridge in Ohio. This bridge would have the capacity for two additional traffic lanes if the 

pins behaved as pins. However, the pins have seized, and the resulting analysis has shown that two 

lanes of traffic needed to be removed. 

In another example, one pin was removed because NDE concluded that it was cracked. Upon removal, 

no crack was found. Yet another example, the load rating of one bridge in Ohio is governed by steel pins 

whose condition cannot be evaluated because of inaccessibility. The majority of a pin’s surface is 

covered by the plates it connects, and so typically the ends are the only features that are visible. In some 

cases, the geometry of the connection is such that only one end of a pin is accessible.

D. Robert Hay (Waves in Solids LLC, State College, PA) presented an overview of (1) short-term 

monitoring systems of acoustic emission with associated strain that have been deployed by Waves in 

Solids LLC, (2) the role of these systems in risk-informed management of bridge maintenance, and (3) 

active (conventional) ultrasonic technology (UT) inspection methods.

George Hearn (Associate Professor, University of Colorado, Boulder) provided an introduction to the 

inspection discussion by pointing out different types of inspections, the motivation for any deviation in 

inspection intervals, and thresholds for decision making with reference to Connecticut, Oregon, and 

Michigan’s inspection guidelines. 

Sougata Roy (Senior Research Scientist, ATLSS Engineering Research Center, Lehigh University, 

Bethlehem, PA) presented an overview of orthotropic decks. Even though orthotropic decks can provide 

life spans exceeding 100 years and are considered an ABC technique, their implementation in the US is 

rare because of the high initial cost and potential for fatigue cracking if the fabrication quality is low. The 

most critical weld is the rib-to-deck weld because of its tight tolerances. Many fabricators do not want 

to specify a tighter tolerance weld because of the higher level of sample preparation, welder 

competence, and inspection required for that type of weld. A protocol for welds specific to orthotropic 

decks is desired, specifically distinguishing between a small versus a large discontinuity, as it would

permit evaluation of what welds need to be repaired and which are acceptable. PAUT was highlighted as 

a potential NDE technique, but it requires standards and guidelines for use. The development of 

standard, consistent protocols, and guidelines for automated application would naturally fall within 

NIST’s mission.
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C. Discussion 

The stakeholders identified fifteen bridge inspection topics during the breakout session. The first six are 

those topics that were deemed most important by the stakeholders and are listed in order of decreasing 

rankings in the final plenary vote. 

1. Buried steel – determining location, size, and condition (corrosion) of concrete passive or 

prestressed reinforcement.

Determining the size and condition of reinforcing steel in hardened concrete (including obsolete 

rebar types) is a measurement need. Older bars have different surface deformations (raised 

pattern) than modern bars. Very old bars are smooth. A new technology to see inside concrete 

elements must be proven on old bars, since their surfaces are so different. Bridge records 

would ideally consist of many items [American Association of State Highway and Transportation 

Officials 2008]; an illustrative selection of items for this discussion includes construction plans, 

shop drawings, as-built plans, specifications, and material certifications. The need for 

information on existence, location, type, and amount of buried steel in structures is not limited 

to older structures where construction plans and/or as-built drawings do not exist; it is also 

desired for younger structures for confirmation of current and future performance with 

calculations or justification for a proposed repair. Strands in post-tensioned members provide 

another venue for determination of the location and condition of inaccessible members. 

2. Inspection reference specimens for validation of methods 

This discussion hinges around justification and confidence in many NDE techniques (particularly 

ground penetrating radar (GPR), PAUT, and UT) where the DOTs would like to provide more data 

to justify their preferred action. Standardized and certified visual output greatly improves the 

confidence of owners and ensures that the technicians employing the technique are interpreting 

it properly. Mike Loeffler’s presentation illustrated the effect of not having accurate conclusions 

from NDE technologies. Development of reference specimens for buried as well as surface 

cracks was raised during the session. Another vein of this topic brought up the desire to 

automate or build in a post-processor for the output of some NDE techniques such that a 

qualified (yet not necessarily experienced) user would be able to make precise conclusions 

about the member’s actual condition. The suggestion was to provide locations where NDE 

providers could obtain a third-party validation of their devices, setup, and conclusions. This idea 

fits well within NIST’s mission to provide independent calibration, evaluation, and validation of 

measurement tools. 

3. Visual inspection detection rates and validation

Visual techniques dominate inspection methods defined in the NBIS. Inspections of fracture 

critical bridges consist of a very detailed visual inspection “that may be supplemented by 

nondestructive testing” *Electronic Code of Federal Regulations 2010]. FHWA published a report 

that showed that inspectors do not always satisfactorily locate or identify defects on reference 

specimens [Moore 2000]. Specific topics related to the visual inspection and probability of 

detection (POD) study were to define standards that defined a critical defect, the rate of 
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detection relative to the defect’s size (specifically of fatigue cracks), and the relation of critical 

defects to detectable defects. Studies of these topics could provide a basis for modification of 

existing inspector training courses. 

4. Data mining applied to inspection data

Analysis of data recorded from inspections (past data sets) offers the potential of optimizing 

maintenance effectiveness, scheduling, remaining life, and basic degradation rates. There is a 

need for employing inspection data (existing and new) in better software-based decision-aiding 

tools. Ideally, these applications would provide interfaces with existing software for ease of use. 

5. Steel pins and rivets—methods for condition determination and validation of conclusions

Although pin and rivet connections do not dominate new construction, certain classes of bridges 

in the existing inventory contain large quantities of these connections, which are sometimes 

inaccessible and, therefore, difficult to inspect. Methods are needed for determining the 

condition of these connections, including quantifying section losses in connections with multiple 

plies.

6. Validation methods for training received

This topic is very similar to topic 3 with the slight distinction of focusing more on the ability of 

the inspector, rather than the type of defect, and external factors that may affect identification 

and description of problem areas. 

7. Corrosion

Existing devices that detect and characterize corrosion need to be validated. Magnesium 

chloride (MgCl2) is known to aggravate the corrosion of steel members, so standards for 

material performance and rates of corrosion that account for various de-icing programs and the 

local climate are also desired. Magnesium chloride has replaced sodium chloride at some DOTs, 

and road sand replaces it at some others. Any salt is bad for bridge steel, but sodium chloride 

(NaCl) has been thought by some to be more harmful than MgCl2. In Colorado, road sand has 

contributed substantially to particulate pollution (as measured by the P10 indicator of air 

quality). Therefore, Colorado DOT has reduced its use of sand and, correspondingly, increased 

its use of MgCl2, even though salt is detrimental to bridges. The ability to measure the corrosion 

of buried steel elements, such as steel straps in MSE walls and rock bolts, was also mentioned. 

8. Standards for inspecting inaccessible or poorly accessible elements are desired to guide 

procedures for sampling, destructive testing, and replacement.

Scour is the most frequent cause of bridge collapse, but inspection of scour damage is difficult, 

because of lack of visibility and stressful inspection situations (difficult and sometimes 

hazardous underwater working conditions for divers). Therefore, guidance on inspection of 

underwater piers is needed, so that it can be performed in the most effective and timely 
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manner. A review of existing technologies for detection and monitoring of scour, leading to 

guidelines for bridge owners, was also suggested. 

9. Monitoring 

Standards that extend Florida DOT’s work on long-term monitoring of cracks in steel and the 

provision of artifacts that can be used for calibration of crack lengths and expected growth rates 

are desired. This applies both to surface and buried cracks. Monitoring of the remaining 

population of bridges (or elements) of the same type after a failure was suggested as a 

measurement and data need. 

10. There is a need to validate load capacity determination with sensor technologies and FEM, 

which includes appropriate boundary conditions and the stress history of the bridge. 

11. Validation of techniques that determine the condition of inner plies of steel connections (gusset 

plates) is needed.

12. Field measurements of total and residual stresses.

One application for the absolute stress device would be distinguishing between distortioninduced stress and direct stress. Growth in the distortion-induced stress may exhaust the spare 

capacity in the original design. 

13. Potential for monitoring movement of structures with a more accurate GPS-type device (with 

millimeter resolution) was suggested.

14. Metrology is needed for determining the depths of unknown foundations. 

15. Metrology is needed for determining the effects of multiple applications of heatstraightening on 

the material locally and the bridge globally.

II. Advanced Sensors

A. Introduction

The principal foci of the Advanced Sensors session were the development, standardization, and 

validation of sensors, data transmission/compression, and data analysis/interpretation for long-term 

and short-term monitoring of bridges. Other closely related topics discussed in these sessions 

overlapped with those in the session on Uncertainty in Inspection Information, and these included the 

development and validation of devices and methods for periodic NDE investigation of bridge 

components.

B. Presentations

Catherine French (I.T. Distinguished Professor, Department of Civil Engineering, University of 

Minnesota, Minneapolis) reviewed the permanent instrumentation, data acquisition, and structural 

modeling of the new I-35W St. Anthony Falls Bridge. The University of Minnesota is responsible for 

sensor-data collection and interpretation over the first three years and for development of a long-term 

monitoring system. 
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Larry Olson (Olson Engineering, Wheat Ridge, CO) reviewed impact-echo methods and laser-based 

methods employed by Olson Engineering to characterize concrete delamination and bridge deflection, 

respectively.

C. Discussion 

The stakeholders identified fourteen technical areas in which research would serve to advance SHM of 

bridges. The first seven of these areas are listed in the order of their ranking in the final plenary session. 

1. Absolute and residual stress measurements and reference specimens

A number of types of sensors are currently commercially available or in the process of being 

developed for measuring changes in quasi-static strain relative to that at the time of installation 

of the sensor. However, methods are not established for accurate and cost-effective field 

measurements of absolute stress or strain, and such data are desired for determining how close 

metals are to their yield point. In the absence of such metrology, the initial state of stress in 

new bridges can only be estimated from the design, unless initial stresses in the unloaded stage 

are measured with permanently mounted sensors during the entire construction process. In 

older bridges, engineering estimates of stress based on the design generally have large margins 

of uncertainty, because of unknown structural history, such as settling of piers and impact 

damage. To address this situation, NIST could perform research on methods for absolute-stress 

measurements in the field and develop artifacts for validation of methods. 

2. Environmental and aging effects on sensors for long-term monitoring

New bridges are designed to have lifetimes of many decades, but no sensors currently being 

installed for structural monitoring have been tested over such long periods of time. This raises 

questions about whether such sensors will survive and provide reliable data over the lifetime of 

a bridge. For example, measurements provided by vibrating-wire strain gages on the new I-35W 

bridge are dependent on the tension of the metallic wires, which may drift over time because of 

relaxation of the wires. NIST could potentially provide impartial research and evaluation of such 

degradation, leading to standardized accelerated-test procedures.

3. Standard testing apparatus (test beds) for SHM technologies

No mechanisms or standards exist for impartial validation of the performance of many new SHM 

technologies. This places end users, such as state DOT engineers, in the difficult position of 

deciding on the usefulness of committing great long-term resources to the deployment of 

technologies that have been validated only by the manufacturers with non-standardized tests. 

To address this situation, NIST could develop and house standardized apparatus for evaluating 

SHM sensors and instrumentation. This apparatus could include testbeds with elements that are 

either destroyed during the tests (for example, with known time-dependent fatigue damage) or 

that remain constant (for example, with known static strain, curvature, displacement, 

vibrational modes, or defects). 
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4. Corrosion sensors 

Corrosion of steel reinforcements and prestressing strands is a major cause of structural 

deterioration of reinforced concrete bridges. Because such corrosion occurs at internal material 

interfaces, it cannot be detected through visual inspection. Therefore, the development of 

sensors for detecting and characterizing the extent and rate of corrosion is a high priority.

5. Calibration acceptance and rejection criteria

Data obtained from NDE inspection can be complex and difficult to interpret on real structures 

in the field, and this leads to ill-defined acceptance/rejection criteria. An example of this is 

phased-array ultrasonic testing (PAUT), which provides information on discontinuities within 

structural components in the form of spatial maps. NIST could help to resolve this problem by 

establishing calibration methods and systematic methods for evaluating data.

6. Micro-electro-mechanical systems (MEMS) or other low-cost technologies that measure 

acceleration, strain, or displacement

The costs of sensors and instrumentation for processing sensor data are major obstacles to the 

practical realization of widespread SHM of bridges. MEMS offer particularly great promise for 

reducing costs and associated complexity of mechanical sensing and signal processing through 

wafer-level fabrication and integration of electronics. A potential role of NIST in this area is the 

invention and development of MEMS or other low-cost sensors for characterizing acceleration, 

quasi-static and/or dynamic strain, large-scale displacement, or local displacement. 

7. Frameworks for sensor selection and placement

Determining an approach for efficient and cost-effective deployment of SHM sensors on a 

structure can be a complex process, involving an analysis of principal structural vulnerabilities 

and related properties/parameters, and, from these, selection of optimal sensor types and their 

placement. The broad expertise and impartial perspective of NIST place it in position where it 

could effectively help establish guidelines for sensor selection and placement. 

8. Sensors for alkali-silica reaction (ASR)

ASR is a chemical reaction between the cement and aggregate of concrete that causes

expansion and cracking. Microscopy techniques are employed in the laboratory to detect such 

reaction, but detection in the field, before obvious structural degradation, is much more 

challenging. New, inexpensive, fast, easy, and reliable methods for early detection of ASR in the 

field are required to enable early mitigation of weakened bridges [Cooley 2006]. 

9. Wireless, robust, self-powered sensors with on-board processing

The cost of installing wiring to power sensors on bridges is a major impediment to widespread 

deployment of networks for structural health monitoring. The cost and complexity of processing 

large amounts of data from such sensing networks are also impediments. Wireless sensors with 

on-board data processing could overcome these problems. However, currently available 
17

wireless sensors are limited with respect to their robustness and battery life. Therefore, the 

development of new sensors with long-term reliability, self-sustaining power, and integrated

data processing (minimizing the volume and complexity of transmitted data) is a high priority.

10. Sensing of fatigue cracks

Monitoring the initiation, growth, and state of fatigue cracks in steel is required for effective 

risk-based assessment of priorities for bridge repairs or replacement. Various approaches, 

ranging from periodic visual inspection to short-term acoustic-emission sensing, have been

pursued, but none has been demonstrated to provide a reliable and cost-effective long-term 

solution. Practical sensors and associated electronics and algorithms for signal- and dataprocessing are needed for long-term unattended monitoring of fatigue cracks.

11. Data-compression methods

Digital processing and analysis of large volumes of data generated by hundreds (or, potentially, 

thousands) of sensors in a network on a bridge are major challenges. Therefore, developing 

methods and establishing protocols for data compression is a high priority.

12. Protocols for networking and communication of sensor arrays specific to bridges

Standards for sensor network structure, in relation to the hierarchy and paths of communication 

and the format of transmitted data, are not established. Differing opinions on this topic were 

expressed at the workshop. On the one hand, NIST, as an impartial agency with expertise in 

information technology, could expedite progress in this technical area, with a focus on 

nonproprietary algorithms and code. On the other hand, an NDE supplier expressed the opinion 

that technical advances in this field would best be developed privately, because users are 

already employing commercially produced algorithms and related instrumentation that 

overcome some of the networking challenges 

13. Tools for data interpretation

Methods of data interpretation, including modeling strategies and algorithms, are not fully 

established or standardized for either NDE inspection or new SHM sensor networks. NIST would 

play a useful role by developing analytical tools and establishing guidelines for choosing 

approaches to the analysis of specific types of measurements.

14. Guidelines for structural health monitoring of new bridges, starting with construction

Uncertainty in the quantification of the mechanical state of new bridges is introduced by 

incomplete or indirect information on initial dead-load conditions (stress or strain in the 

absence of applied traffic load). Rather than relying on engineering calculations of stresses and 

strains based on the idealized bridge design, it is preferable to obtain direct measurements that 

serve as a baseline for subsequent time- and load-dependent sensor data. An appropriate role 

for NIST in this area may be to provide guidelines for monitoring strain during the process of 

construction. New bridge construction is increasingly focused on accelerated bridge 
18

construction (ABC) methods, which are dominated by prefabricated concrete sections. 

Therefore, any approach for obtaining baseline sensor data during construction must address 

these techniques and materials. 

III. Behavior of Connections

A. Introduction

This summary documents the discussion in the Tuesday and Wednesday breakout sessions. Some 

background material has been added that did not appear in the discussion. Much of this information is 

referenced to research results and documents that the participants mentioned during the discussion.

At the close of the session, the participants reviewed the potential research areas that they had raised 

during the discussion. The research topics naturally fell into three groups: (1) timely, important, and 

NIST-suitable; (2) important but not suited for NIST research areas; and (3) not discussed in detail. After 

selecting the first group, the stakeholders voted by show of hands on the importance of each topic 

within the group. 

B. Presentations

Karl Frank (Hirschfeld Industries, Austin, Texas, recently retired from the University of Texas at Austin) 

reviewed connection design and construction issues, including the need for a new mid-strength bolt, the 

use of epoxy bearing bolts and fillers, and galvanizing-treatment effects on weld cracking.

Todd Helwig (University of Texas at Austin) reviewed the effects of cross-frame connections on bridges 

with skewed supports and construction difficulties with bridges with curved girder systems.

Arturo Schultz (University of Minnesota) presented research on structural health monitoring for 

response modification of bridges. 

C. Discussion

The stakeholders identified six research areas that were deemed timely, important, and potentially 

suited for NIST research. They are listed below in descending order of significance as ranked during the 

final plenary session by the stakeholders.

1. Methods to rapidly determine load rating of bridges 

An on-going problem is determining the load rating for new and existing bridges. The discussion 

of this research area ranged quite widely. Participants were clear that methods that used strain 

gages on bridges were not rapid. They did include the possibility of using a diagnostic load test. 

One participant speculated that the ideal system for producing a bridge’s load rating would be 

able to take a photo, digitize it, and input the results to an analysis tool. The methods need to be 

simple and robust, so much so that a “guy from the county department” can use them. Another 

opined that low-cost meant the ability to characterize twenty bridges per day. Another 

possibility would be to use methods that monitored the ambient vibration level by use of the 

live load of the bridge itself. 

Apparently, the Army Corps of Engineers is conducting similar research devoted to rapid rating 

of bridges for force projection, due to the weight of military equipment (Chowdhury and Ray, 
19

2003). Ian Friedland pointed out that a FHWA project exists in this area (NCHRP 12-78 

scheduled to be completed 3/2/2010). 

Fuchs described an existing FHWA program to implement a laser system that could measure 

bridge deflections during fabrication [Fuchs 2004]. The discussion in the breakout session 

centered on the entire laser system. This system would have the capability to determine the 

actual load rating without reference to the original plans. 

2. Improved crack-arrest strategies 

Two separate issues were joined in the discussion of this area: (i) dynamic fracture toughness 

requirements to incorporate crack arrest in design of fracture critical members, and (ii) better 

ways to arrest fatigue cracks, supported by more experimental results, especially for distortioninduced cracks. 

The advent of high-performance steels (HPS) with enhanced toughness may provide crack-arrest 

capability in fracture critical members. Wright has discussed potential application of highperformance steels and the FHWA perspective [Wright 2002]. Development of toughness 

requirements coupled with large size tests to validate performance in welded fabricated girders 

would accelerate the use of HPS. The payoff would be reduced inspection costs when higherstrength steel requires fewer members Distortion-induced cracking is the most prevalent form 

of cracking in steel bridges. Bridges built through the 1970’s contain numerous locations 

susceptible to this form of fatigue cracking. The cracks form where differential displacements of 

the structure elements are concentrated in local gaps between connection elements. Typically, 

these are slow-growing fatigue cracks that initially are no cause for concern. However, as they 

grow, the cracks can turn and become normal to the bending stress in the girders. Reliable 

methods of arresting these cracks are needed. Traditionally, hole drilling at the crack tip 

followed in some cases by the insertion of a tightened high-strength bolt has been used. This 

and other techniques have not always been successful. A fracture mechanics analysis of existing 

and new techniques is needed. The results should be verified by laboratory and field studies. 

3 Methods for inspecting multiple plies for corrosion 

A method for detecting corrosion underneath multiple-ply plates, such as are found in gusset 

plates, would be extremely useful. Current ultrasonic methods are defeated by the reflections 

from the interfaces between the plates. Ian Friedland pointed out that the FHWA TurnerFairbank Research center is currently evaluating two commercial methods for identifying buried 

corrosion. 

4. Methods for determining bolt pretension 

Methods for determining the bolt tension in a connection in the field could help assess the 

condition of connections. Some participants noted that the existing, commercial ultrasonic 

devices required the bolts to be machined at both ends, and that this requirement made the 
20

devices cost-prohibitive. An affordable device could also be useful for rivets. Many existing

bridges use riveted, rather than bolted, connections. 

Existing, commercial ultrasonic strategies typically use length measurements made 

ultrasonically before and after tightening. These methods may also require specially prepared

bolts. Some research already exists on methods that do not require the bolt to be measured 

beforehand. These use the difference between shear and pressure waves to determine the 

actual stress state in the bolt [Jhang 2006, Kim 2009, Toda 2000, Walaszek 2006]. Some of these 

use electromagnetic (EMAT) instead of piezoelectric transducers. It is not clear what fieldperformance tests have been completed, and how effective the technique is on real bolts.

5. Retrofits for cable hangers for fire protection

The anchorages for suspenders in suspension bridges and cable hangers in arch bridges are 

vulnerable to fire at the deck level, for example, from a tanker fire [Zoli 2007]. The socket is 

attached to the wire rope by brooming out the ends of the wire rope and potting them in either 

molten zinc or epoxy. Zinc melts at approximately 400 °C, and epoxy is limited to about 200 °C. 

Little data exists on the strength degradation of epoxy with temperature. The issue extends 

beyond suspension bridges, since cable-stayed bridges, stadiums, and glass-wall buildings all use 

socketed cables or wire ropes. These structures have high occupancy, and failure could lead to 

large loss of life. Methods to retrofit these existing systems to improve their reliability at 

elevated temperatures are needed as well as development of new systems that are not 

vulnerable during a fire. Furthermore, the research could take advantage of a unique NIST 

facility, the 35 MN tensile test machine on the Gaithersburg campus (53 MN in compression, 35 

MN in tension).

6. Acoustic Emission 

Although the participants acknowledged that a separate breakout session was devoted to 

inspection strategies, they chose to discuss acoustic emission characterization, as it related to 

connections. They identified four areas of particular concern: (1) developing lower-cost sensors, 

(2) improving signal processing of AE signals, (3) developing new or improved communication 

protocols for ad hoc networks, and (4) developing improved accept/reject criteria for what 

constitutes a non-noise signal.

IV. Mechanical Response of Materials

A. Introduction

This summary documents the discussion in the Tuesday and Wednesday breakout sessions.

At the close of each session, the stakeholders reviewed the potential research areas that they had raised 

during the discussion. The research topics naturally fell into three groups: (1) timely, important, and 

NIST-suitable; (2) important but not suited for NIST research areas; and (3) not discussed in detail. After 

selecting the first group, the stakeholders voted by show of hands on the importance of each topic, and 

selected the top five to present during the final plenary session. 
21

B. Presentations

Theodore Zoli (HNTB) presented a broad overview of the topic of bridge failure due to extreme events. 

Truss bridges are overrepresented in bridge failures in the US (defined as inability to carry live loads, not 

necessarily catastrophic). Flooding is a more frequent cause of damage than scour. Impact often renders 

many truss bridges unstable, but collapse is rare, fortunately, because typically bridge columns are 

designed for impact, although bridge decks are not. In AASHTO LRFD (Load and Resistance Factor 

Design), non-redundant bridges are designed for only 5 % more load than redundant bridges. A bridge 

failure database is needed.

Dennis Mertz (University of Delaware) commented briefly on the need to clarify the difference between 

a subjective description of a bridge condition (used for allocation of funds) and load rating by testing 

(that has little to say about actual failure). He further discussed the measured behavior of a structure 

versus the calculated behavior based on the overdesign for safety. He pointed out the need to 

understand the uncertainties and assumptions for all of these measurements and designs.

Todd Helwig (University of Texas Austin) reviewed issues associated with curved girder design and 

erection modeling. He pointed out the need to understand how certain reports define “failure.”

C. Discussion

The stakeholders identified eight research needs, described below in descending order of significance as 

indicated by votes during the final plenary session (not as ranked in the breakout session).

1. Resistance to fire 

The behavior of high performance steel (HPS) at temperatures ranging between 400 °C and 

1100 °C needs to be better defined for use in design and analysis.

Fires from tanker trucks present a danger to bridges. Guidance is needed for bridge design, 

repair, and replacement, as well as fire-fighting strategies (cooling the fire, particularly steel 

members with water, evacuating the bridge, commitment of fire-fighting personnel, etc.). It 

usually takes two hours before a tanker truck fire can be brought under control. Double-deck 

bridges are particularly vulnerable, as tanker accidents, spills and fires can occur on the lower 

deck, thus exposing the upper deck to flames. Asphalt pavement can do more than burn; it can 

also act as a sponge for fuel. 

The Throgs Neck Bridge fire is an example of fire damage on deep girders with thin webs 

(slenderness ratio approaching 200) whose strength after a moderate-temperature wood fire 

was difficult to evaluate because of web buckling. Thin webs are much more difficult to 

straighten than flanges. Guidance is also needed as to how many times one can heat-straighten 

steel before the properties of the steel are changed. In another example, a coconut fire under a 

cable bridge ignited the anti-corrosion layer around the cable, exposing a significant 

vulnerability.

The behavior of connections in fires also needs to be better understood, in particular the fatigue 

resistance of bolted and riveted connections, especially when they are loose or exposed to high 
22

temperatures. Connections are typically not designed for member over-strength (that is, 

connected members fail before the connection itself fails).

2. Size (scale) effects 

The strength of structural members and connections is determined by small-scale tests, which 

are not always a faithful representation of full-size behavior. The problem has been studied for 

reinforced concrete members in shear, but is not limited to that. The full-scale tests of steel 

gusset plates at FHWA present a unique opportunity to study this problem for steel connections 

(NCHRP Project 12-84 “Gusset Plate Connections for Steel Bridges”).

3. Load rating, structural deterioration, and monitoring

Changes in emphasis on resilience, robustness, and safety require a reconsideration of load 

rating, which is based on calculations, not necessarily in accordance with physical 

measurements. The problem of scour of bridge piers, in particular, requires better modeling 

and measurements. 

We need a better understanding of the fatigue resistance of bolted and riveted connections, 

especially when they are loose or exposed to high temperatures. Connections are assumed to be 

stronger than the members they connect, but are typically not designed for member overstrength.

4. Resistance to impact 

Most impacts on bridges are caused by trucks whose height exceeds clearance, but barge 

impacts on bridge piers, or even impacts caused by a weather-induced event, are possible. (For 

example, on 29 August 2005, Hurricane Katrina pushed the offshore platform PEMEX's PSS 

Chemul, a 13,000 t semisubmersible accommodation unit that was under renovation, and 

wedged it under the Cochrane Bridge in Mobile, Alabama.) We also need better understanding 

of high strain rate effects. Train and vehicular impacts usually occur at speeds below 90 m/s 

(200 mi/h), but the fighter jet that cut the cables of a funicular in Italy was traveling at more 

than 270 m/s (600 mi/h). Flying objects set in motion by an explosion range in speed from 

180 m/s (400 mi/h) to 610 m/s (1320 mi/h).

Instrumenting a bridge before explosive demolition is an attractive way to better understand 

progressive collapse and the behavior of members and connections under dynamic loads.

5. NDE for corrosion detection below protective coatings or plies 

Corrosion and fatigue are perennial problems for steel bridges. The measurement of section loss 

due to corrosion in steel plates of multiple plies is a problem in bad need of solution. It is also 

desirable to be able to monitor by NDE the condition of the structure through protective 

coatings.
23

6. Dynamic behavior of bridge cables 

We need to better understand the dynamic behavior of cable anchors on suspension bridges. 

Are we under-predicting wind forces against bridges, especially flutter? Cables also retain 

memory of the capstan used to draw them (typical diameter 1.5 m (5 ft)), and their cracking can 

often be traced to the curvature of the capstan.

If hydrogen embrittlement can be alleviated, galvanizing prestressing cables may be an 

attractive way to resist corrosion.

7. New fabrication processes 

Explosive forming is used in making machine parts, but not bridge components and connections. 

Why not? Also, friction-stir welding needs to be investigated for use on bridges. 

8. Concrete 

Various issues were identified: early age cracking, transverse cracking of decks, cement 

replacement (to reduce carbon footprint), thermal control for mass concrete, and difficulties in 

slip forming.

Bibliography

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Washington, DC: AASHTO Publications.

Chase, S. B. (2005). The role of sensing and measurement in achieving FHWA’s strategic vision for highway 

infrastructure. In F. Ansari (Ed.), Sensing Issues in Civil Structural Health Monitoring. (pp. 23- 32). Netherlands. 

Springer.

Chase, S. B. & Laman, J. A. (2000). Dynamics and Field Testing of Bridges. Transportation in the new millennium: 

state of the art and future directions. Retrieved 21 June 2010.

http://onlinepubs.trb.org/onlinepubs/millennium/00029.pdf

Chowdhury, M. R. and Ray, J. C. (2003). Accelerometers for bridge load testing, US Army Engineering Research and 

Development Center, Vicksburg, MS 39180-6199, NDT&E International 36 237–244.

Cooley, A. & Brumfield, J. W. (2006). ASR Benchmark Workshop. Federal Highway Administration. Retrieved 22 

June 2010, from http://www.fhwa.dot.gov/pavement/concrete/asrbench.pdf 

Electronic Code of Federal Regulations. (2010). Retrieved 1 July 2010 from 

http://ecfr.gpoaccess.gov/cgi/t/text/textidx?c=ecfr&sid=86dce31d4371c549d6fcfbbb8beefd56&rgn=div6&view=text&node=23:1.0.1.7.28.3&idno=23

Fisher, J., Kulak, G. L., & Smith, I. F. C. (1998). National Steel Bridge Alliance. A Fatigue Primer for Structural 

Engineers. Retrieved 18 June 2010 from http://www.aisc.org/store/p-1590-a-fatigue-primert-for-structuralengineers.aspx
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Friedland, I. (Speaker). (2010). Every Day Counts [Audiovisual presentation]. AASHTO Bridge Meeting, Sacramento, 

CA.

Friedland, I. (2010). Personal e-mail, 8 June 2010.

Fuchs, P. A., Washer, G. A., Chase, S. B., & Moore, M. (2004). Laser-based instrumentation for bridge load testing. 

Journal of Performance of Constructed Facilities. 18(4). 213-219. 

Hartman, J. (Speaker). (2010). NCHRP 12-84 Gusset Plate Connections for Steel Bridges Update [Audiovisual 

presentation]. AASHTO Bridge Meeting, Sacramento, CA.

Jhang, K. Y. & Quan, H. H. & Ha, J. & Kim, N. Y. (2006). Estimation of clamping force in high-tension bolts through 

ultrasonic velocity measurement. Ultrasonics. 44. E1339-E1342. 

Kim, N. & Hong, M. (2009). Measurement of axial stress using mode-converted ultrasound. NDT & E International. 

42(3). 164-169. 

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Symposium. Retrieved 18 May 2010 from 

http://www.aisc.org/WorkArea/linkit.aspx?LinkIdentifier=id&ItemID=20606

Moore, M., Phares, B., Graybeal, B., Rolander, D., & Washer, G. (2000). Reliability of Visual Inspection for Highway 

Bridges. Federal Highway Administration. Retrieved 1 July 2010 from 

http://www.tfhrc.gov/hnr20/nde/pdfs/01021a.pdf

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Toda, H., Go, Y., Yokoyama, K., Yosikawa, O., &Yawata T. (2000). Measurement of axial-stress in high-tension bolts 

by acoustoelastic velocity-ratio method. In Uomoto, T. (Ed.), Non-destructive Testing in Civil Engineering 2000 –

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Structural Engineering and Materials. 4(1). 96-104. 

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image correlation. Experimental Techniques. 31(1). 34-40.

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25

Appendix I – Presentations

I. Keynote Presentations

II. Breakout Session Presentations

III. Supplemental Information

(These presentations are only on the CD version of the report.)
26

Appendix II – Agenda 

Final Agenda

Workshop on Quantitative Tools for Condition Assessment of Aging Infrastructure

Dates: May 4 and 5, 2010 

Location: NIST, Boulder, CO 

Purpose 

This workshop is designed to sharpen the focus of NIST’s Materials Science and Engineering Laboratory 

(MSEL) programs by matching the measurement technology capabilities of MSEL with existing 

technology gaps in the realm of assessing bridge performance to prioritize their repair and replacement. 

The workshop will include approximately 30 stakeholders from universities, professional societies, 

industry, and the DOTs (state and federal departments of transportation). The stakeholders will help 

NIST researchers identify areas that would provide the best application of their skills and to propose 

potential partners for specific projects. The workshop will start with several keynote presentations to 

frame the topics, followed by parallel breakout sessions to develop and rank potential research 

activities. The workshop will conclude with all the stakeholders to develop a consensus and prioritized 

list.

We have identified four tentative topic areas: uncertainty in inspection information, advanced sensors, 

behavior of connections, and materials mechanical response.

Output

The meeting will develop a ranked list of activities that MSEL staff could perform in support of the 

nation’s bridge infrastructure. The results will be published as a NIST Internal Report, and circulated 

within the bridge industry to find partners in our activities. 

Scope

See separate document. 

Steering committee

Frank Gayle, Stephanie Hooker, William Luecke, Tom Siewert

Organizing committee

Stephanie Hooker, Mark Iadicola, Dave McColskey, Tom Siewert, Jessica Terry, Dat Duthinh, Ward

Johnson
27

Schedule

Tues May 4

8:00 Arrive at the Visitor Center at 325 Broadway, Boulder, CO

Receive badge and parking permit, proceed to the north of Building 1 for parking, enter east door at the 

front of Building 1 (faces Broadway) and proceed to room 1107 for light refreshments

8:30 Welcome

Tom Siewert, Project Leader, Materials Reliability Division

8:35 NIST Overview: Organization and Mission 

Frank Gayle, Metallurgy Division Chief

8:50 Overview of MSEL Plan: Quantitative Tools for Condition Assessment of Aging Infrastructure 

Stephanie Hooker, Materials Reliability Division Chief 

9:30 Keynote: Bridge Research: Current Issues and Future Opportunities 

Ian Friedland, Technical Director, Bridges and Structures R&D, FHWA 

10:15 Break

10:30 Keynote: Research Perspective, Overview and Measurement Gaps that MSEL might fill Dan Frangopol, 

Fazlur R. Khan Endowed Chair of Structural Engineering and Architecture, Assessing and predicting the 

performance of bridges to prioritize their repair and replacement: accomplishments and challenges

11:15 Keynote: AISI Bridge Task Force, Overview and Measurement Gaps that MSEL might fill

Alex Wilson, Customer Service Technical Manager, ArcelorMittal

12:00 Lunch

1:15 Role of Breakout Sessions Tom Siewert

1:30 Breakout sessions 

Room 1107 Uncertainty in Inspection Information Leader: George Hearn, Recorder: Jessica Terry

Contributions from

George Hearn, Overview of inspection information issues

Mike Loeffler, Degradation rates, database for new materials 

Sougata Roy, Improved inspection methods for orthotropic deck fabrication

Room 1103/5 Materials Mechanical Response Leader: Theodore Zoli, Recorder: Dat Duthinh

Contributions from

Theodore Zoli, Overview of mechanical response issues

Todd Helwig, Curved plate girder design

Dennis Mertz, Steel bridge evaluation

3:30 Break

3:45 Breakout Sessions

Room 1107 Advanced Sensors Leader: Steve Lovejoy, Recorder: Ward Johnson

Contributions from

Steven Lovejoy, SHM of bridges 

Catherine French, I-35W Sensors

Room 1103/5 Behavior of Connections Leader: Karl Frank, Recorder: William Luecke

Contributions from

Karl Frank, Overview of connection issues

Art Schultz, SHM of gusset plates in FC bridges

5:45 Meeting Adjourns
28

Weds May 5

8:30 Resume Breakout Sessions

Room 1107 Uncertainty in Inspection Information

Leader: George Hearn, Recorder: Jessica Terry

Contributions from:

Mike Loeffler, Test standards for large steel pin testing

Room 1103/5 Materials Mechanical Response 

Leader: Theodore Zoli, Recorder: Dat Duthinh

Contributions from:

Dennis Mertz, Redundancy in steel bridges

Art Schultz, Enhanced safety of bridges

9:30 Breakout Sessions

Room 1107 Advanced Sensors 

Leader: Steve Lovejoy, Recorder: Ward Johnson

Contributions from:

Steven Lovejoy, Fatigue and fracture of bridges

Catherine French, Consideration for the development of real-time dynamic testing using 

servo-hydraulic actuation

Room 1103/5 Behavior of Connections 

Leader: Karl Frank, Recorder: William Luecke

Contributions from:

Karl Frank, Fatigue strength of welded cruciform joints 

Todd Helwig, Cross-frame connections effect on steel bridges with skewed supports

Sougata Roy, Fatigue critical details in orthotropic decks

10:30 Break

10:45 Report Conclusions and Action Items

Tom Siewert

Uncertainty in Inspection Information

Behavior of Connections 

Advanced Sensors 

Materials Mechanical Response

11:30 General Discussion and Closing 

Tom Siewert

12:00 Lunch

1:30 MSEL Tours: 

Materials Labs in Boulder

Atomic Clock, Building 1

Bulk Mechanical Testing Facilities, Building 2

Mechanical Testing and Pressurized Hydrogen, Building 12

Steel recovered from Big Thompson Canyon bridges, Building 8
29

Appendix III – Topic Rankings 

Stakeholders were each given six votes to be distributed in whatever categories or weighting they chose, 

with the possibility of multiple votes from any individual for any topic. The voting stakeholders 

included: five bridge owners, eleven university researchers, and nine industry personnel. The rankings 

are ordered according to the total number of stakeholders’ votes.

Topic

Bridge OwnersUniversityIndustryTotal

1. Sensors – absolute and residual stress measurements and reference 

specimens

8 6 4 18

2. Connections – methods to rapidly determine load rating of bridges 2 6 4 12

3. Connections – improved crack-arrest strategies 3 4 3 10

4. Inspection – buried steel; determine location, size, and condition 

(corrosion) of concrete reinforcement; determine location, force and 

condition (corrosion) in prestressing steel

3 4 3 10

5. Sensors – environmental and aging effects on sensors for long-term 

monitoring

0 5 4 9

6. Inspection – inspection reference specimens for validation of 

methods

2 3 4 9

7. Inspection – visual inspection detection rates and validation 1 6 1 8

8. Sensors – standard testing apparatus (test beds) for SHM 

technologies

1 3 4 8

9. Material Response – resistance to fire 2 2 3 7

10. Material Response – size (scale) effects 1 3 3 7

11. Material Response – load rating, structural deterioration, and 

monitoring

1 4 2 7

12. Inspection – data mining applied to inspection data 0 5 1 6

13. Sensors – corrosion sensors 1 2 3 6

14. Connections – methods for inspecting multiple plies for corrosion 3 1 2 6

15. Connections – methods for determining bolt pretension 0 3 2 5

16. Sensors – calibration acceptance and rejection criteria 0 2 3 5

17. Material Response – resistance to impact 0 4 1 5

18. Inspection – steel pins and rivets; methods for condition 

determination and validation of conclusions

1 1 2 4

19. Connections – retrofits for cable hangers for fire protection 0 2 1 3
30

Topic

Bridge OwnersUniversityIndustryTotal

20. Sensors – MEMS or other low-cost technologies that measure 

acceleration, strain, or displacement

1 0 2 3

21. Sensors – frameworks for sensor selection and placement 0 0 1 1

22. Material Response – NDE for corrosion detection below protective 

coatings or plies

0 0 1 1

23. Inspection – validation methods for training received 0 0 0 0

 
31

Appendix IV a – Stakeholders

Anderson, Jeffrey Colorado DOT

Atadero, Rebecca Colorado State University

Connor, Robert Purdue University

ElSafty, Adel University of North Florida

Frangopol, Dan Lehigh University

Frank, Karl Hirschfeld Industries

French, Catherine University of Minnesota

Friedland, Ian FHWA

Goldstein, Neil JenTek Sensors

Hay, D Robert Waves in Solids, LLC

Hearn, George University of Colorado

Helwig, Todd University of Texas

Lane, Susan PCA

Loeffler, Michael Ohio DOT

Lovejoy, Steven Oregon DOT

McEleney, William NSBA

Merritt, James PHMSA/DOT

Mertz, Dennis Delaware University

Mulligan, Denis Golden Gate Bridge, Highway and Transportation District

Nowak, Andy University of Nebraska, Lincoln

Olson, Larry Olson Engineering

Piazza, Mark Pipeline Research Council International, Inc

Roy, Sougata Lehigh University

Schultz, Arturo University of Minnesota

Sinha, Sunil Virginia Tech

Snyder, Dan AISI

Verma, Krishna FHWA

Wilson, Alex ArcelorMittal/AISI Bridge Task Force

Zavattieri, Pablo Purdue University

Zoli, Theodore HNTB
32

Appendix IV b – NIST Participants

Baker-Jarvis, James Electromagnetics Division

Drexler, Elizabeth Materials Reliability Division

Duthinh, Dat Metallurgy Division

Fekete, James Materials Reliability Division

Gayle, Frank Metallurgy Division

Hamstad, Marvin Materials Reliability Division

Hooker, Stephanie Materials Reliability Division

Iadicola, Mark Metallurgy Division

Johnson, Ward Materials Reliability Division

Luecke, William Metallurgy Division

McColskey, David Materials Reliability Division

McCowan, Chris Materials Reliability Division

Richards, Mark Materials Reliability Division

Siewert, Tom Materials Reliability Division

Sowards, Jeffrey Materials Reliability Division

Surek, Jack Electromagnetics Division

Terry, Jessica Materials Reliability Division

Weeks, Timothy Materials Reliability Division