A

 comprehensive study of the

reliability of Visual Inspection of

highway bridges was recently conducted

by the NDEVC. The goal of this 2-year 

study was to determine the accuracy and 

reliability of bridge inspection as

implemented by State DOTs.

The study involved having bridge

inspectors from 25 States complete 10

inspection tasks on 7 of the NDEVC test 

bridges. Seven of these inspections were 

Routine Inspections, while three were InDepth Inspections. In addition, one of

the Routine Inspections was performed

as a State-Dependent Inspection where

inspectors performed the inspection

using their home State data collection

and recording procedures.

Forty-nine State bridge inspectors

participated in the field testing portion of 

the study. This group included

inspectors of diverse backgrounds,

qualifications, and persona l 

characteristics. 

Routine Inspection Results

Routine Inspections are the standard

bridge inspections that are performed on 

the majority of the bridges in the United 

States. One of the goals of these

inspections is to rate the condition of the 

primary elements of the bridge on a 0 to 

9 scale. 

Overall, there is significant variability in 

the assignment of condition ratings. The 

results indicate that approximately 68

percent of condition ratings will vary

within ± 1 condition rating point from

the average, and 95 percent will vary

within ± 2 points. An average of

between four and five different condition 

ratings were assigned to each primary

element of the bridges inspected.

In-Depth Inspection Results

In-Depth Inspections are close-up, 

hands-on inspections completed on a

portion of a bridge. These inspections 

are usually implemented with the intent

of locating specific deficiencies that may 

exist in the bridge. In this study, two InDepth Inspection tasks were performed

on steel superstructures.

It appears that an In-Depth Inspection

completed by a State bridge inspector

may not detect many of the types of

deficiencies for which it is frequently

prescribed. For example, the correct call 

rate for identifying crack indications

during one of the inspection tasks was

only 4 percent. The correct call rate for

identifying defective bolts was 24

percent. In another In-Depth Inspection 

task, only 7 percent of the inspectors

correctly identified the crack indication.

A few factors seemed to relate to the In-

(Continued on page 4)

Inspector checking behind the end floor beam.

Volume 2, Issue 1

Visual Inspection Results Finalized, Published

Spring 2001

T

he NDEVC has recently provided

technical assistance to the FHWA

D.C. Division Office in relation to a

structure in the District of Columbia. A 

wingwall adjacent to a bridge abutment

on the Whitehurst Freeway had been

experiencing large amounts of water

flow from weep holes in the structure. 

Since the abutment is adjacent to the

C&O Canal, there were concerns that

the water flow was due to a leak in the

canal wall. Initial visual observations of 

the wingwall showed movement relative 

to the abutment. 

To determine future structural

movement and to access the 

effectiveness of any repairs to the canal, 

a continuous monitoring system was

(Continued on page 3)

Inside this issue:

Visual Inspection Results 1

Wingwall Sensor 1

Project Updates 2

PC Box Girder Testing 3

NDEVC Staff Roster 4

Wingwall Kept in Check by NDEVC

U.S. DEPARTMENT OF TRANSPORTATION FEDERAL HIGHWAY ADMINISTRATION

NDEVC News • Spring 2001 FHWA-RD-01-088 1
M ost States currently require some level of shop assembly of fabricated 

steel bridge members. The NDEVC is continuing to work on

developing a laser-based system that could provide virtual assembly of these

bridge members, eliminating the need for physical shop assembly. Further

proof-of-concept tests have been completed and the project is likely to move

into an advanced testing phase in the near future. For further information,

contact Paul Fuchs at (202) 493-3095.

A

utomated ultrasonic testing (UT) is an inspection technique ideally suited 

to the inspection of butt welds created during the bridge fabrication

process. The NDEVC is working on aiding in the transfer of automated UT

technology to this industry. Proof-of-concept tests were recently conducted at 

High Steel Structures, Inc. in Lancaster, PA. These tests showed that

automated UT can provide results similar to those gained from manual UT and 

from radiographic testing (RT). The advantage of automated UT is that it

provides both permanent storage of inspection data and multiple views of the

data, thus aiding in its interpretation. A parallel testing study, including

automated UT, manual UT, and RT, is expected to commence soon. For

further information, contact Glenn Washer at (202) 493-3082.

C

oncern about overhead sign structure and light pole failures has led many 

State DOTs to reevaluate their inspection procedures for these highway

structures. The NDEVC is in the process of surveying States to determine

how these inspections are completed and what sort of problems are generally

found. A market survey of techniques currently available to inspect these

structures is also being performed, along with research into promising

techniques. In addition, a task group is being formed to bring together States 

interested in disseminating pertinent information and sharing their experiences 

with these structures. For further information, contact Dennis Rolander at

(202) 493-3120.

T

he NDEVC is continuing its work on the ultrasonic inspection of bridge 

hanger pins. The goal of the current work is to develop a procedure for 

the inspection of pins that can be used by State transportation agencies that are 

either inspecting pins themselves or contracting for inspection services. The

resulting report will include a description of general hanger pin inspection

procedures, including cleaning requirements, scanning patterns, use of angle

beam transducers, available sizing techniques, and interpretation of signals. In 

addition, a general description of the types of documentation usually required

and of inspector qualifications and certifications will be developed. For further 

information, contact Brent Phares at (202) 493-3121.

Project Updates

2 NDEVC News • Spring 2001

NDEVC NEWS is the newsletter of 

the Federal Highway Administration’s 

Nondestructive Evaluation Validation

Center.

The NDE Validation Center was

established by the Federal Highway

Administration in 1998. The objective

of the NDEVC is to improve the state of 

the practice for highway bridge

inspection. The Center is designed to

act as a resource for State transportation 

agencies, industry, and academia

concerned with the development and

testing of innovative NDE technologies. 

The NDEVC provides State highway

agencies with independent evaluation

and validation of NDE technologies,

develops new NDE technologies, and

provides technical assistance to States

exploring the use of these advanced

technologies. 

The NDE Validation Center utilizes a

series of unique resources to evaluate

and assess the factors affecting the

reliability and performance of NDE

systems. The Validation Center is

located at the Turner-Fairbank Highway 

Research Center in McLean, Virginia. 

To supplement the capabilities of these

laboratory facilities, a series of bridges

located in Northern Virginia and

southern Pennsylvania are utilized to

conduct field investigations. In

addition, a collection of component test 

specimens are used in various test

programs.

NDE Program Manager

Glenn Washer

(202) 493-3082

glenn.washer@fhwa.dot.gov

NDE Validation Center

(202) 493-3118

Fax: (202) 493-3126

www.tfhrc.gov

Steel Bridge Virtual Shop Assembly

Automated UT of Butt Welds

Overhead Sign Structure Inspection

Procedure for UT of Hanger Pins
T

he third in a series of full-scale 

tests of prestressed-concrete box

girders was recently completed at the

Turner-Fairbank Highway Research

Center. These 40-year-old girders were

donated by the New York State DOT

after having been removed from service

due to severe deterioration. The goal of 

the testing was to improve the

knowledge base for the behavior of

bonded composite laminates used in

retrofitting deteriorated concrete beams.

The five donated girders were each

approximately 21.5 m (70 ft) long and

had depths of 0.84 m (33 in). 

Deterioration of the bottom flange of the 

girders caused these girders to be

removed from service. The deterioration 

included spalling concrete, corroded 

strands, and broken strands.

In practice, a number of States have

recently become interested in retrofitting 

the bottom flange of this type of girder

with bonded composite laminates. The

retrofits are designed to replace any loss 

of strength that may have occurred due

to deterioration. 

The first two tests in the series were on

girders that had not been repaired. 

These tests provided information on the

pre-repair strength and behavior of the

girders. 

The third girder was repaired on site at

TFHRC. The repair included removal of 

deteriorated bottom flange concrete,

patching of spalled areas, and

application of the composite laminate

repair material. A carbon fiber laminate 

was used for this test. The application of 

the laminate included applying multiple 

layers of the composite in three strips

along the bottom flange.

The testing of the girders was completed 

by the application of loads at two load

points, each 1.5 m (5 ft) from midspan. 

Four 445-kN (100-kip) hydraulic jacks

were used. The girder was instrumented 

to measure horizontal and vertical

deflection, as well as strain in the

concrete and the laminate. 

A number of NDE techniques were also

used throughout this testing. Prior to

testing, the Virginia Polytechnic Institute 

NDE team assessed the quality and

presence of the adhesive bond between

the laminate and the

concrete. This testing was 

performed with infrared

thermal imaging. Also

prior to the test, NDT

Engineering, Inc . 

performed sonic testing on 

the concrete to determine

its strength. During the

test of the repaired girder, 

Physical Acoustic s 

Corporation assessed the

condition of the concrete

prestressing strands 

through the use of acoustic 

emission monitoring. 

New York State DOT is in 

the process of analyzing

the results of the three box 

girder tests.

NDEVC Tests Prestressed-Concrete Box Girders

(Continued from page 1)

designed and built specifically for this

application. The purpose of the system

is to measure the long-term movement of 

the wingwall relative to the abutment. 

An innovative part of the instrument is a 

low-cost electromagnetic displacement

sensor, designed and built for this

application by the NDEVC. The

monitoring system has been providing

information on the condition of the

structure since installation in midAugust.

This project was coordinated with the

cooperation of Kathleen Linehan,

FHWA D.C. Division Office Structural

Engineer. Further information on this

project can be obtained by contacting

Paul Fuchs at (202) 493-3095.

The fiber-composite plates debonded at the conclusion of the test. This photograph was taken at the moment of failure.

NDEVC News • Spring 2001 3

Wingwall Kept in Check . . .
Glenn Washer, P.E. – FHWA NDE Program Manager

 (202) 493-3082 glenn.washer@fhwa.dot.gov

Steve Chase, Ph.D – FHWA Infrastructure Inspection and 

 Management Team Leader

 (202) 493-3038 steve.chase@fhwa.dot.gov

Mark Moore, P.E. – Project Manager

 (404) 577-7444 mmoore@wje.com

Fariba Parvizi – Administrative Support

 (202) 493-3118 fariba.parvizi@fhwa.dot.gov

Paul Fuchs, Ph.D. – Research Engineer

 recent work: Laser, Instrument Development

 (202) 493-3095 paul.fuchs@fhwa.dot.gov

Ben Graybeal – Research Engineer

 recent work: Visual Inspection, Ultrasonics, Laser

 (202) 493-3122 benjamin.graybeal@fhwa.dot.gov

Brent Phares, Ph.D. – Research Engineer

 recent work: Visual Inspection, Ultrasonics

 (202) 493-3121 brent.phares@fhwa.dot.gov

Ali Rezaizadeh, Ph.D. – Research Engineer

 recent work: Radar, Acoustic Emission

 (202) 493-3119 ali.rezaizadeh@fhwa.dot.gov

Dennis Rolander – Research Engineer

 recent work: Visual Inspection, Overhead Sign Structures

 (202) 493-3120 dennis.rolander@fhwa.dot.gov

Habeeb Saleh, Ph.D. – Research Scientist

 recent work: Radiography

 (202) 493-3123 habeeb.saleh@fhwa.dot.gov

Mike Scott, Ph.D. – Research Engineer

 recent work: Radar, HERMES II

 (202) 493-3124 michael.scott@fhwa.dot.gov

NDEVC Staff Information

4 NDEVC News • Spring 2001

(Continued from page 1)

Depth Inspection results. They include time to complete

inspection, comfort with access equipment and heights, and

flashlight use.

Deck Delamination Survey

The third In-Depth Inspection task focused on the

delamination survey inspection of a concrete bridge deck. The 

inspectors worked in pairs to complete the mechanicalsounding-based survey. The bridge deck showed few outward 

signs of distress; however, it was approximately 19 percent

delaminated.

This portion of the study showed that the accuracy of deck 

delamination inspection is relatively poor. Few teams

provided maps that could be considered to accurately portray

the condition of the deck. Also, only about one-quarter of the 

teams provided overall delamination percentages within 5

percentage points of the actual amount. 

State-Dependent Inspection

During one of the Routine Inspections, the inspectors were

asked to complete the inspection as if the bridge were located 

in their home State and were part of their bridge inventory. 

Unlike in the other tasks, the inspectors used their own

inspection forms and followed their home State inspection

format (i.e., element-level inspection and/or condition rating

inspection). 

This portion of the study showed that most States follow

similar inspection procedures and provide the same general

information in

their inspection

results. However,

the presentation of

the reports varied

greatly, as would

be expected. Also, 

approximatel y 

two-thirds of the

States tha t 

participated in this 

study presented

element-level data. 

The use of element-level inspection elements was generally

consistent with the FHWA Commonly Recognized (CoRe)

Element Guide. 

Concluding Remarks

Visual inspection of highway bridges is critical to the

continued fitness of our Nation’s infrastructure. This study

established a benchmark for the state-of-the-practice and

should help to ensure the continued advancement of visual 

inspection techniques for years to come.

Further information can be obtained by contacting the

NDEVC or by referencing FHWA Report Nos. FHWA-RD-01-

020 and FHWA-RD-01-021, which contain the complete

results of the study.

Visual Inspection Results 

Crack indication in a tack weld.

FHWA-RD-01-088