TECHBRIEF Foundation Characterization

Program (FCP): TechBrief #1—

Workshop Report on the Reuse

of Bridge Foundations

By James G. Collin and Frank Jalinoos

FHWA Publication No.: FHWA-HRT-14-072

FHWA Contact: Frank Jalinoos, HRDI-50, 202-493-3044, 

frank.jalinoos@dot.gov

Introduction

This TechBrief presents the results of a workshop held at 

the 2014 Transportation Research Board (TRB) 93rd annual 

meeting on the reuse of bridge foundations. The workshop 

is the continuation of ongoing effort by the Federal 

Highway Administration (FHWA) to identify research 

and development needs with respect to foundation 

characterization program (FCP). This program includes 

the development and/or evaluation of new and existing methodologies for characterizing existing bridge 

foundations for the determination of unknown geometry, 

material properties, integrity, and load-carrying capacity.

The transportation system in the United States includes 

more than 600,000 bridges built for grade separation, 

interchange configurations, and crossings over natural 

barriers such as rivers. The operation and functionality 

of the highway network depends on the performance of 

these structures. As of December 2012, the National Bridge 

Inventory (NBI) included 607,380 structures (bridges and 

culverts) with a span greater than 20 ft (6 m).(1) Of those 

structures, 36,076 bridges over waterways (riverine 

and tidal) are identified as having unknown foundations. 

The term “unknown foundation” has been associated 

with the population of existing bridges over waterways 

that cannot be evaluated for hydraulic vulnerability 

related to scour. The number of bridges over 

land with unknown foundations, however, is not known 

because this qualifier is not a reportable item in the NBI.

Research, Development, and 

Technology

Turner-Fairbank Highway 

Research Center

6300 Georgetown Pike

McLean, VA 22101-2296

www.fhwa.dot.gov/research
2

On January 16, 2013, a multidisciplinary 

taskforce was formed by FHWA at the 

TRB 92nd annual meeting consisting 

of 14 FHWA and State transportation 

department stakeholders. The taskforce 

members were selected based on their 

recognized expertise in the areas of 

unknown foundation and foundation 

assessment issues. During this meeting, 

the taskforce met and brainstormed on 

steps needed to move forward with a 

multiyear strategic research plan for 

unknown foundations. The consensus of 

the taskforce and FHWA management 

was to broaden the scope of the research 

program from “unknown foundations” 

to “foundation characterization” and 

incorporate several related issues such as 

multihazard concerns, changes in service 

loads, and foundation reuse.

A workshop was held in Arlington, VA, 

from April 30 to May 1, 2013, to solicit key 

stakeholders’ input and was summarized in 

the Characterization of Bridge Foundations 

Workshop Report (FHWA-HRT-13-101).(2) The 

following summary and recommendations 

are a result of that workshop: 

1. A key issue with unknown foundations 

is their characterization. 

2. Much good work is being done in the 

States with the reuse of foundations. 

States have their own individual procedures; there is no ready means of 

assessing the present practice. 

3. The main issues for foundation reuse 

are their condition assessment, their 

load-carrying capacity, their remaining 

service life, and how the reuse of foundations interacts with new codes. 

4. Research and development on foundation reuse will also benefit unknown 

foundations. 

In support of foundation characterization 

and reuse, the following specific recommendations were made:

1. Research is needed for load testing of 

existing foundations and better methodologies for condition assessment.

2. Research is needed for instrumenting 

new foundations (“smart piles”) or 

existing foundations for on-demand 

assessment of condition.

3. A synthesis of common practices on 

foundation reuse should be developed 

as soon as possible. 

4. Guidelines for field evaluation of unknown and known foundations should 

be developed to include site investigation, destructive and nondestructive

testing or monitoring, numerical modeling, and load testing.

5. Guidance for the reuse of foundations 

is needed and should include consideration of structural, hydraulic, and 

geotechnical issues in a holistic manner.

In support of the workshop recommendations, an open workshop (workshop 160) 

and a separate session (session 395) on the 

reuse of bridge foundations were held at 

the 2014 TRB 93rd annual meeting. Table 1 

lists the presentation topic and speakers 

for the TRB workshop, and table 2 lists the 

speakers for the separate session.
3

Paper Number Presentation Title Author/Speaker

W160-01 FHWA Characterization of Bridge 

Foundation Workshop Frank Jalinoos, FHWA

W160-02

Research on Foundation Reuse at 

BAM (presented by Dr. Herbert 

Wiggenhauser)

Ernst Niederleithinger, Federal Institute 

for Materials Research and Testing (BAM) 

W160-03

Issue and Challenges with 

Foundation Reuse at North Carolina 

DOT

Mohammed A. Mulla, 

North Carolina Department of 

Transportation

W160-04

Experience with Evaluation and 

Reuse of Bridge Foundations at 

Massachusetts DOT

Peter Connors,

Massachusetts DOT

W160-05 Virginia DOT I-95 Bridge 

Rehabilitation: Substructure Repairs

Joe Hardee,

URS Corporation

W160-06

Henley Bridge Rehabilitation Project 

with Emphasis on Original Historic 

Design

Saieb Haddad, 

Tennessee DOT

W160-07

Reuse of Foundation at Arthur Mills 

Crossing Railroad Bridge, Salt Lake 

Valley, Utah

Jon E. Bischoff, 

Utah DOT

W160-08 Ohio DOT Experience with 

Foundation Reuse

Jawdat Siddiqi,

Ohio DOT 

None Workshop Roundup Jerry A. DiMaggio, TRB

Table 1. Topics and speakers for workshop 160, “Characterization of Foundations of Bridges and Other Structures 

for Reuse.”

 1FHWA DISCLAIMER: Please note you are accessing a non-government link outside of FHWA, U.S. Department of 

Transportation (DOT). Our standard FHWA Web sites have many links to other organizations, including educational 

institutions and non-profit associations. Please note: While links to Web sites outside of DOT are offered for your 

convenience in accessing transportation-related information, please be aware that when you access non-DOT Web sites, 

the privacy policy—including tracking technology, computer security, and intellectual property protection—and Section 

508 of the Rehabilitation Act (accessibility requirements) no longer apply. In addition, DOT cannot attest to the accuracy, 

relevancy, timeliness, or completeness of information provided by linked sites. Linking to a Web site does not constitute an 

endorsement by DOT or any of its employees of the sponsors of the site or the products presented on the site. For more 

information, please view DOT’s Web site linking policy.

TRB COMMITTEES AFP30 DISCLAIMER—The information contained in this Web site is maintained by members of the 

TRB committee AFP30. Information included here does not imply an endorsement by the TRB, the National Academy of 

Sciences, or the National Research Council.

The presentations are available on the 

TRB Committee on Soil and Rock Properties (AFP30) Web site.(3) It is accessible 

at https://sites.google.com/site/

trbcommitteeafp30/characterizationof-bridge-foundations. 1
4

Paper Number Presentation Title Author/Speaker

S395-01 Evaluating Foundations for Reuse: 

Looking Ahead 

Benjamin Rivers, 

FHWA

S395-02 Issues of Risk and Liabilities Relating 

to Reuse of Existing Foundations 

Dan Brown, 

Dan Brown and Associates

S395-03

Reuse of Structural Foundations: 

Engineering and Program 

Management Considerations

Jerry A. DiMaggio, 

TRB

S395-04 Testing and Modeling of Pile and 

Shaft Foundations for Reuse

Michael C. McVay, 

University of Florida

S395-05

Potential of Structural Identification 

Method for Reusing Existing Bridge 

Foundations

A. Emin Aktan, 

Drexel University

S395-06

Henley Bridge Rehabilitation Project 

with Emphasis on Original Historic 

Design

Pamela Moore, 

GCI Incorporated

This TechBrief summarizes the key issues, 

findings, and recommendations that were a 

result of the TRB workshop 160 and session 

395.

Drivers for Bridge Foundation Reuse

U.S. Transportation Sector Perspective

In both the workshop and panel discussion 

session, numerous speakers identified the 

following drivers and reasons for reuse of 

bridge foundations:

• Asset management. Existing foundations 

are assets with a functional value.

• Technical drivers. Replacing piles may 

be difficult.

• Time savings. Using existing foundations would minimize impacts on 

mobility.

• Economic drivers. Reusing bridge 

foundations would lead to direct and 

indirect cost savings.

• Efficiency. Reusing bridge foundations 

is a viable option for replacing structurally deficient superstructures.2

• Past performance. The foundation has 

performed adequately in the past; in 

essence, it has been load tested.

• Environmental benefits. The use of 

existing foundations would have a more 

limited impact on the environment.

• Sustainability issues. Reusing bridge 

foundations would save resources.

• Historic preservation considerations. 

Existing foundations would be better 

suited for structures with historical 

value.

European Perspective

The Reuse of Foundations for Urban Sites 

(RuFUS) was a European Union-funded 

research project centered on setting 

guidelines to allow foundations (predominately building foundations) to be reused 

more often; the project was completed 

Table 2. Topics and speakers for session 395, “Reuse of Bridge and Other Structural Foundations.”

 2Given that close to one-quarter of bridges in the NBI are identified as deficient (either structurally deficient or 

functionally obsolete), the potential savings for the bridge owners in reusing existing bridge foundations is significant.
5

in 2006.(4,5) The project partners were BRE 

(coordinator), Arup and Cementation 

Foundations Skanska from the United 

Kingdom, Soletanche-Bachy from France, 

the Technical University of Darmstadt 

and BAM from Germany, Stamatapoulos 

Associates from Greece, and the Swedish 

Geotechnical Institute. 

A major part of the RuFUS initiative was 

to demonstrate to construction teams that 

foundation reuse is a viable, reliable alternative that is not completely novel (i.e., a 

research project). The end result of RuFUS 

was a set of guidelines for the reuse of 

existing foundations.(4,5)

Dr. Niederleithinger presented the results 

of the RuFUS research at the workshop. 

From the European perspective, he 

identified the following reasons for reuse of 

existing foundations:

• Ground congestion (utilities, tunnels, 

neighboring foundations).

• Archaeology (e.g., long-term delays 

after Roman structure discovery).

• Construction technical drivers (difficulty in replacing piles).

• Economic drivers (cost savings).

• Environmental / sustainability issues 

(limited use of resources).

Reuse Applications and Challenges

Reuse applications for bridge foundations identified by the participants of the 

workshop and panel discussion included 

replacement of the superstructure of 

an existing bridge because of structural 

deterioration, widening of an existing 

bridge, repurposing (i.e., using an existing 

railroad bridge foundation for a pedestrian/bike path), and reuse with enhanced/

strengthened foundation and accelerated 

bridge construction (ABC)/prefabricated 

bridge elements and systems (PBES).

However, there are many challenges to 

the reuse of existing foundations. The

evaluation of the suitability of an existing 

bridge foundation for reuse is a multidisciplined task that needs to involve 

structural, hydraulic, geotechnical, and 

construction expertise. The following list 

is composed of the challenges for reuse 

as presented by the speakers at both the 

workshop and the panel discussion:

• Normally, the current design specifications and geometric standards 

require a larger structure and therefore 

an increase in foundation loads.

• Foundations may lack critical 

documentation.

• There is a lack of confidence in as-built 

plans. 

• Construction and monitoring standards at the time of the original 

construction were different. 

• Foundations set on soft, compressible 

soils may not be suitable for reuse.

• States lack means to reduce and 

account for uncertainty.

• Existing foundations may have experienced critical levels of deterioration. 

• There is a lack of reliability of existing 

and new field methods to characterize 

current conditions and remaining 

service life.
6

• Cultural change and its impact may 

affect the use of existing foundations.

• States must determine the standard of 

care for designers in evaluating reuse.

• States must determine how and/or 

if to incorporate load and resistance 

factor design (LRFD) into reuse of 

foundations.

• Risk and liability issues may be 

associated with the reuse of existing 

foundations, not only for the State but 

also the design consultant (if outside 

services are used) and the contractor.

• There is a lack of existing State and/or 

Federal guidelines.

Selective State Practice and Policies

Prior to the workshop, several State 

transportation department workshop 

participants briefly collected information 

from a few nearby States on the extent 

of foundation reuse. The North Carolina 

Department of Transportation (NCDOT) 

created a simple spreadsheet with specific 

questions regarding reusing existing foundation for rehabilitation, replacement, or improvement. Table 3 summarizes the results.

From this limited dataset, it is clear that 

the majority of State transportation departments have reused existing foundations in 

one form or another. However, as discussed 

below, very few State transportation departments have established specific policies or 

guidelines.

Table 3. Summary of foundation reuse by NCDOT and other State transportation departments.

State 

transportation 

department

Has your State reused 

existing foundations for 

bridge replacement?

Has your State improved 

or fixed existing bridge 

foundations to mitigate 

for additional load, scour, 

seismic activity, etc.?

Are policies and guidelines 

available to evaluate existing 

foundations?

ALDOT No Yes No

CDOT Yes No No

Caltrans No Yes No

INDOT No Yes No

KYTC Yes Yes No

MnDOT Yes Yes No

NYSDOT Yes Yes No

NCDOT Yes Yes No

TDOT Yes Yes No

UDOT Yes No No

ALDOT = Alabama Department of Transportation.

CDOT = Colorado Department of Transportation.

Caltrans = California Department of Transportation.

INDOT = Indiana Department of Transportation.

KYTC = Kentucky Transportation Cabinet.

MnDOT = Minnesota Department of Transportation.

NYSDOT = New York State Department of 

Transportation.

NCDOT = North Carolina Department of Transportation.

TDOT = Tennessee Department of Transportation.

UDOT = Utah Department of Transportation.
7

Massachusetts 

Foundation reuse is written into the Massachusetts bridge manual.(6) Massachusetts 

Department of Transportation (MassDOT) 

policy on reuse of existing foundations is 

represented in bridge replacement, bridge 

rehabilitation, or superstructure replacement projects. Reuse of bridge foundations 

is allowed if the existing foundations have 

no scour issues or structural deficiencies, or 

if they can be rehabilitated to meet current 

American Association of State Highway 

and Transportation Officials (AASHTO) 

LRFD specifications and have their service 

life extended for at least another 75 years. 

The reuse strategy is evaluated during 

preliminary engineering, when as many 

of the project parameters as possible are 

optimized without violating the project 

constraints. This evaluation includes 

investigation, testing, and analysis. The 

merits and cost of rehabilitating the existing 

foundation are presented in a preliminary 

structures report. If the existing foundation 

is not deemed to be serviceable for reuse 

in the new bridge structure, then the merits 

of reusing the existing abutments and 

wingwalls as an earth-retaining structure 

or scour protection independent of the 

new bridge structure are considered. In 

addition, if the bridge to be replaced is 

historic, found in a historic area, or is in 

sensitive wetlands, then the abutments 

may be retained without being incorporated into the new structure to minimize

the impacts on those resources. For 

superstructure replacement projects or 

bridge rehabilitation projects involving 

a historic structure, the requirements to 

design these projects in accordance with 

the current AASHTO LRFD specifications 

are modified to meet the anticipated truck 

traffic loadings or past editions of the 

AASHTO specifications. These exemptions 

require prior written approval from 

MassDOT.

North Carolina

NCDOT has no specific guidelines or policy 

for reuse of existing foundations. Current 

state of practice for NCDOT for low-impact 

bridges (i.e., bridge maintenance bridges) 

founded on timber piles is to reuse the 

foundation from the pile cap or column 

down, and repair damage to the cap or 

column if necessary. However, the majority 

of bridges in North Carolina are replaced 

with new foundations. 

Ohio

Based on the 2006 FHWA LRFD guidance 

that states, “For modification to existing 

structures, States would have the option 

of using LRFD specifications or the 

specifications which were used for the 

original design,” the Ohio Department of 

Transportation has elected to use the 

specification for driven piles that was 

in place at the time of the design of the 

original structure. However, for drilled 

shafts and spread footings, Ohio uses the 

following LRFD specifications:

• Driven piles. For driven piles to bedrock, 

reuse is based on the structural 

capacity of the pile. For friction piles, 

if they were originally designed based 

on the pile driving formula, then the 

geotechnical limit/capacity is verified 

by dynamic testing.

• Drilled shafts. For drilled shafts socketed into bedrock, the State controls 

structural limits. For friction drilled 

shafts, the State controls geotechnical 

limits, and reuse is generally not 

permitted. 
8

• Spread footings. For spread footings on 

rock, the State controls structural limits. 

For spread footing on soil, the State 

controls geotechnical limits and both 

structural and geotechnical analysis.

Illinois

As described in the previous FHWA workshop report, Illinois has a formal and 

elaborate methodology for evaluating 

foundation reuse.(2) The new policy, issued 

in 2008, allows an abbreviated analysis 

when the substructure is in good or repairable condition and the dead load increase 

is less than 15 percent.

Utah

Utah does not have a specific policy on the 

reuse of existing foundations and has only 

completed two projects to date in which 

existing foundations were reused.

Field Testing

The workshop and panel discussion did 

not focus directly on methods to verify 

foundation conditions. However, the presenters briefly discussed the following 

options:

• Pile integrity testing.

• Parallel seismic.

• Ultrasonic echo.

• Half-cell potential.

• Ground-probing radar.

• Surface resistivity testing.

• Material testing.

• Unload monitoring (example presented 

by Michael C. McVay3).

• Load rating of foundations based on 

finite element method analysis and 

settlement criteria (example presented 

by Pamela Moore).

• Structural identification for bridge load 

testing (as presented by Ahmet Emin 

Aktan).

• Foundation static load test. 

• Foundation dynamic load test.

Foundation Options for New and 

Existing Bridges

Four options for new developments on 

bridge sites with existing deep foundations 

are presented here and illustrated in 

figure 1 through figure 4. 

Option 1 features a new foundation built 

adjacent to an existing foundation. This 

option is perhaps the simplest from an 

engineering and implementation perspective. However, in river crossings, analysis 

is required to account for scour vulnerability due to the pier interference. Vortices 

shedding of adjacent piers can cause 

scour holes to overlap that are deeper than 

from a single pier. Accordingly, the old piers 

are typically removed to an elevation of 

2 ft (0.6 m) below the mud line.

Option 2 features a new in-place foundation. The existing foundation is demolished 

and replaced with a new one. When the 

location of the new structure is required 

to be in the same place as the existing 

structure, removal and replacement of the 

existing foundation is an option, albeit a 

costly one.

 3Please refer to the AFP30 Committee Web site for workshop presentations: https://sites.google.com/site/

trbcommitteeafp30/characterization-of-bridge-foundations.
9

Option 3 features the complete reuse of the 

existing foundation. This option requires 

characterization of the existing foundation. 

Option 4 features the reuse of existing 

foundation while at the same time strengthening and enhancing the capacity of the 

foundation by extending the pile cap, including drilled shafts; using micropiles; implementing soil improvement measures such 

as compaction grouting and permeation 

grouting; and so forth. The enhancement of 

the existing foundation is an obvious way 

to reduce the risk associated with option 3. 

Innovative ABC/PBES techniques can 

be implemented with option 4, as seen 

in the Milton-Madison Bridge.4 Figure 5 

shows a preassembled steel truss superstructure (placed on temporary piers) 

that was moved laterally 55 ft (16.7 m) on 

refurbished piers.(7) Four of the five main 

piers were reused, but the pier stem had 

to be widened. Soil structure interaction 

was evaluated for the existing foundations, 

which were ultimately strengthened by coring and adding supplemental reinforcing to 

the existing pneumatic caisson foundation.

Table 4 lists case histories from the workshop presented in the next section and the 

foundation reuse option that was used in 

each case.

Case Histories from the Workshop

Hurricane Deck Bridge, Missouri (Option 1)

An example for option 1 is the Hurricane 

Deck Bridge at Lake of the Ozarks, MO. 

Hurricane Deck Bridge crosses the main 

channel of the Lake of the Ozarks at 

approximately mile marker 35. It carries 

Missouri Highway 5 between Versailles and 

Camdenton. The bridge was built in 1936, 

5 years after the new Lake of the Ozarks 

was filled; prior to that time, traffic crossed 

by ferry. Because of deterioration of the 

bridge and increased traffic volume, a 

replacement/widening project was initiated by the Missouri Department of Transportation in 2005. After extensive study 

of the existing foundation, the project was 

bid with the option to reuse the existing 

foundation or use a new foundation. The 

low bid contractor chose to use a new foundation. The photo in figure 6 was taken 

during demolition, indicating pier position 

of the replacement bridge in relation to an 

old pier. 

Bridge B-23-005-M-18-002, Massachusetts 

(Option 2)

MassDOT replaced a two-span bridge 

between the towns of Bridgewater and 

Middleborough in Massachusetts. Bridge 

B-23-005-M-18-002, which carries Summer 

Street over the Taunton River, was replaced 

with a single-span, integral abutment bridge. 

The new pile-supported integral abutments 

eliminated bridge joints and were placed 

behind the existing abutments and wing 

walls (figure 7). Placing them behind these 

existing structures minimized work in water, 

provided temporary earth support to build 

the new bridge, and provided additional 

scour protection. The existing structures 

were modified by cutting them down to an 

elevation that would allow future inspection 

of the new bridge.

 4One of the reasons to reuse foundations is ABC/PBES. For a complete bridge replacement, a full environmental impact 

statement may be required, which can delay the project significantly. This requirement is avoided by replacing only the 

superstructure.
10

Figure 2. Bridge foundation, option 2. 

Figure 1. Bridge foundation, option 1. 

Option-1

Option-2
11

Figure 3. Bridge foundation, option 3. 

Option-3

Figure 4. Bridge foundation, option 4. 

Option-4
12

Table 4. Case history examples of foundation reuse.

Case History State Transportation Department Foundation Option No.

Hurricane Deck Bridge Missouri Department of Transportation 1

Bridge B-23-005-M-18-002 Massachusetts Department of Transportation 2

Arthur Mills Bridge Utah Department of Transportation 3

Clipper City Rail Trail Massachusetts Department of Transportation 3

Virginia I95 Corridor Virginia Department of Transportation 3

Yadkin River Bridge 91 North Carolina Department of Transportation 4

Henley Street Bridge Tennessee Department of Transportation 4

©Michael Baker Jr., Inc./www.miltonmadisonbridge.com

Figure 5. The Milton-Madison Bridge after the new steel truss superstructure was laterally moved from temporary piers to 

permanent refurbished piers.(7) 
13

©JB Simpson/www.lakeexpo.com.

Source: MassDOT.

Figure 7. Bridge B-23-005-M-18-002, Bridgewater, MA.

Figure 6. Hurricane Deck Bridge, Lake of the Ozarks, MO.(8)
14

 Source: Utah Department of Transportation.

Arthur Mills Bridge, Utah (Option 3)

The Arthur Mills Bridge in Salt Lake Valley, 

UT, was constructed in the 1960s to allow 

vehicular traffic on State Route 201 to pass 

over an existing railroad line. The original 

bridge was a three-span, reinforcedconcrete bridge; the center bents and 

abutments were supported by spread 

footings designed for an allowable bearing 

capacity of 4,000 psf (192 kPa). The bridge 

was reconfigured in 2013 to eliminate the 

existing abutments and shorten the bridge 

from three spans to one span. The existing 

bents were to be converted into abutments 

with the addition of mechanically stabilized 

earth (MSE) walls (figure 8). Four new 

borings were performed as part of the geotechnical evaluation for the reconfiguration. 

The geotechnical report concluded that the 

existing bridge foundations were not 

anticipated to be adversely affected by 

the MSE wall backfill, and a strength limit 

bearing resistance of 14,000 psf (670 kPa) 

may be used for existing bridge footings, 

assuming a resistance factor of 0.45 is used. 

Settlement was estimated to be between 

1⁄2 and 3⁄4 inch (1.3 and 1.9 cm) owing to 

the MSE fill.

Justification for using the existing foundation for the reconfiguration was based on 

the following factors:

• New footings would require excavation 

and shoring at tight locations 

supporting the railroad.

• A larger span to avoid the railroad 

would be costly.

• A new structure would impose less 

load than the old structure.

• Builders had confidence in as-built 

plans of existing structure.

• The performance of existing footings 

was excellent.

• The existing foundation was on 

excellent soil.

Figure 8. Reconfiguration of the Arthur Mills Bridge.(9)
15

Clipper City Rail Trail, Massachusetts (Option 3)

MassDOT repurposed the existing railroad 

bridge to carry the Clipper City Rail Trail 

over Merrimac Street in Newburyport, MA. 

The granite block abutments were originally 

built in 1850. Because of the good condition 

and past performance of the existing granite block abutments (figure 9), they were 

reused. The anchor bolts that secured the 

rehabilitated superstructure were replaced, 

railroad tracks and ballast were removed, 

and hardwood decking was installed as a 

riding surface (figure 10).

Source: MassDOT.

Source: MassDOT.

Figure 9. Clipper City Rail Trail Bridge.

Figure 10. Clipper City Rail Trail bridge deck replacement.
16

Virginia I95 Corridor (Option 3)

The Virginia Department of Transportation 

(VDOT) made the decision to reuse the 

existing foundations with ABC/PBES 

(figure 11) on 10 bridges along the I95 corridor for several reasons. First, the dead 

load was reduced by about 7 percent with 

the use of lightweight concrete decks in 

the replacement superstructures. The 

original foundations were analyzed with 

this reduction in dead load and the 

proposed loading. The analysis indicated 

that the existing foundations were 

adequate to support the new superstructure and the imposed loads. The 

second item considered was cost. Substructure repair and corrosion-protection 

costs were computed and compared 

against replacement cost. The most costeffective solution was to repair and provide 

the corrosion protection for the existing 

foundations. Finally, VDOT did not want to 

disrupt traffic for the length of time that 

would have been required to rebuild the 

existing foundations. Because the existing 

foundations were found to be adequate 

for the proposed loads, the decision was 

made to repair and provide corrosion protection for the existing foundations and 

reuse them. The corrosion protection for 

the prestressed concrete and steel H-pile 

foundations included electrochemical 

chloride extraction and sacrificial corrosion 

protection systems.

Source: URS Corporation.

Figure 11. ABC/PBES on I95 in Virginia.
17

Yadkin River Bridge 91, North Carolina (Option 4)

The Yadkin River Bridge 91 is located in 

Forsyth County, NC. In 2005, distress in the 

superstructure was observed (figure 12). 

It was determined that bent #7 had settled and rotated, causing the distress in 

the superstructure (figure 13). A team of 

structural, geotechnical, and hydraulic 

engineers was tasked with evaluating the 

problem. Divers inspected the foundation

of the pier and assessed the bearing 

materials and scour. Divers were 

instructed to use an airlift to try to remove 

any loose material below the foundation, 

down to the bedrock. Using the airlift, 

the divers were able to reach below the 

footing. However, 4 ft (1.2 m) below the 

bottom of the footing, no bedrock was 

found. Material under the footing consisted 

of cobble, sand, and silt. The original 

design was to have the footing for the piers 

embedded 6 inches (15.2 cm) into rock. 

However, at pier #7, the footing was 

founded on residual soil, and scour over 

the years had removed support, resulting 

in the pier tilting (figure 14). The remedial 

solution for this bent was to enhance the 

foundation with micropiles to provide the 

additional support lost due to the scour 

(figure 15 and figure 16). No discussion 

was presented on how the design load for 

the micropiles was determined or what the 

capacity of the existing pier foundation 

was. This case history presents the 

remediation of an existing foundation 

because of the effects of scour and 

raises the question or perhaps points out 

the need for a definition of foundation 

reuse, because many engineers would 

suggest this action is remediation and not 

reuse.

 1 inch = 2.54 cm

Source: NCDOT.

Figure 12. Yadkin River Bridge superstructure distress.
18

Source: NCDOT.

Source: NCDOT.

Figure 14. Scour at the upstream edge of the pier. 

Figure 13. Yadkin River Bridge Bent #7 settlement and rotation.
19

Source: NCDOT.

Source: NCDOT.

Figure 15. Yadkin River Bridge micropiles remediation.

Figure 16. An existing foundation strengthened with micropiles. 
20

Henley Street Bridge, Tennessee (Option 4)

The Henley Street Bridge, constructed in 

1931, is a six-span, reinforced concrete 

bridge across the Tennessee River. The 

bridge required significant structural repair 

and seismic upgrade. In addition, the width 

of the bridge was expanded. Figure 17 

shows the bridge before rehabilitation, 

and figure 18 shows some of the structural 

deterioration. This rehabilitation project 

was in reality a complete superstructure 

replacement. The original bridge foundation consisted of driven piles. To support 

the added load from the bridge widening, 

additional drilled shafts were incorporated 

into the foundation system (figure 19). 

Underwater inspection of the existing piers 

was performed and given a structural and 

scour rating of 7 out of 10. Based on this 

inspection and engineering judgment, the 

existing foundation was considered to be 

adequate for reuse. The load-carrying 

capacity of the existing foundation was 

assumed to be 20 percent of the total foundation load. Therefore, the drilled shafts 

were designed to carry the remainder of 

the load. How the load capacity of the existing foundation was determined was not 

included in the presentation of this case 

history. Figure 20 shows the bridge after 

rehabilitation.

 Source: Tennessee Department of Transportation.

Figure 17. Superstructure repair, Henley Street Bridge rehabilitation project. 
21

Figure 18. Structural deterioration of Henley Street Bridge superstructure.

Source: Tennessee Department of Transportation.

Source: Tennessee Department of Transportation.

Figure 19. Combined foundation system for Henley Street Bridge rehabilitation.
22

Discussions

It is a common practice in the United States 

to undertake significant improvements on 

existing bridges (new decks, major rehabilitation, widening, and load capacity 

improvements) without consideration 

and study of the current condition and 

remaining service life of the substructure, 

including the foundations. As the specialty topic of bridge preservation becomes 

more mature, a growing number of bridge 

owners are questioning the soundness of 

this practice and are in need of guidance 

at both a bridge-program level and a 

project-specific level to develop and 

implement consistent practices. This topic 

was addressed at recent workshops and 

sessions at the 2014 TRB meeting. The 

workshop and sessions were very well 

attended, validating the importance 

of the topic and the need for further 

research and development work in this 

area. FHWA is just beginning a research 

program that focuses on foundation 

characterization to provide answers to 

meet this challenge.

At first examination, the question of 

whether to reuse existing foundations 

appears simple and, in fact, is often seen 

as a non-issue. If the existing structure is 

visually sound and not experiencing lateral, 

vertical, total, or differential deformation, 

then one may logically assume that substructure is sound and may serve in a 

satisfactory manner for long extended 

service life. However, in some cases, this 

assumption needs to be corroborated 

through field testing.

The workshop presentations and panel 

discussions highlighted different aspects 

of the reuse of bridge foundations. The 

frequency with which this topic is raised 

in practice (although under a variety of 

different titles and terms) is increasing.

Workshop presenters addressed their 

 Source: Tennessee Department of Transportation.

Figure 20. Henley Street Bridge after completion of the rehabilitation.
23

personal and organization experiences to 

date. Collectively, this workshop demonstrated that the apparently simple question 

of whether to reuse existing foundations 

has broad and far-reaching implications 

for owner agencies, designers, and construction staff. For the most part, the topic 

has been considered from a “bottom-up” 

approach, centering on a question raised 

in conjunction with a specific project rather 

than a “top-down” programmatic directive. 

Although the individual presenters did not 

intentionally compare notes or collaborate 

in advance, they suggested that technical 

and management needs in this area are 

many and include the following topics: 

terminology, historical and new data collection and analysis, investigative tools to 

assist in evaluation of structural and geotechnical limit state performance, the in situ 

condition of the foundation material (time 

deterioration and construction placement 

damage), and policies and design protocols.

Research Needs

From a programmatic level, bridge owners require policy, process, and technical 

guidance and tools to adopt a consistent 

approach that ensures public safety, minimizes future risk, and optimizes study scope 

of their bridge inventory. As an example, 

reuse of an existing substructure for a 

bridge deck replacement may not require 

any indepth study as would bridge widening and a completely new superstructure.

It is clear that the majority of the presenters believe that the most important need 

to advance the reuse of bridge foundations 

is the development of FHWA guidelines on 

what is the required standard of practice to 

evaluate an existing foundation and mitigate the risks involved. Each project should 

not be approached as a research project 

but rather as a sustainable construction 

project. The guidelines should clearly define 

reuse because different State transportation departments have different definitions 

of reuse. The guidance should also include 

well-defined approaches to evaluating the 

existing condition of a foundation. How 

much and what type of testing is adequate/

appropriate to define the unknown? What 

disciplines should be involved in the 

foundation assessment?

Additional research into methods of assessing the integrity and capacity of existing foundations should also be pursued. 

However, specifics of this research were not 

provided by the presenters at the workshop 

or panel discussion.

Acknowledgements

We would like to acknowledge the following 

TRB committees for sponsoring the workshop: Soil and Rock Properties (AFP30); 

Foundations of Bridges and Other Structures 

(AFS30), Soil and Rock Instrumentation 

(AFS20), Exploration and Classification of 

Earth Materials (AFP20), Subsurface SoilStructure Interaction (AFS40), and, LowVolume Roads Committee (AFB 30). We 

would also like to acknowledge Dr. Jerry 

Shen of Genex Systems for his assistance.

References

1. FHWA (2012), Bridge—Tables of 

Frequently Requested NBI Information, 

Washington, DC, accessed on August 27, 

2013, http://www.fhwa.dot.gov/bridge/

britab.cfm.

2. Schaefer, V.R. and Jalinoos, F. (2013), 

Characterization of Bridge Foundations 

Workshop Report, FHWA-HRT-13-101, 

FHWA, https://www.fhwa.dot.gov/

publications/research/infrastructure/

structures/bridge/13101/index.cfm.
24

AUGUST 2014 FHWA-HRT-14-072

HRDI-50/08-14(250)E

Researchers—This report was written by James G. Collin of the Collin Group, Ltd. and Frank Jalinoos 

of FHWA R&D. Dr. Collin was a subcontractor to the Genex Systems, LLC through the Turner-Fairbank 

Highway Research Center laboratory support contract DTFH61-11-D-00010. 

For additional information, contact Frank Jalinoos at (202) 493-3082 or in the FHWA office of 

Infrastructure Research and Development, located at 6300 Georgetown Pike, McLean, VA 22101-2296. 

Distribution—This TechBrief is being distributed according to a standard distribution. Direct distribution is being made to the Divisions and Resource Center.

Availability—This TechBrief may be obtained from the FHWA Product Distribution Center by email to 

report.center@dot.gov, fax to (814) 239-2156, phone to (814) 239-1160, or online at http://www.fhwa.dot.

gov/research. 

Key Words—Foundation reuse, prefabricated bridge elements and systems, accelerated bridge 

construction, foundation integrity, bridge substructure, geotech.

Notice—This document is disseminated under the sponsorship of the U.S. Department of 

Transportation in the interest of information exchange. The U.S. Government assumes no liability for 

the use of the information contained in this document. The U.S. Government does not endorse products or manufacturers. Trademarks or manufacturers’ names appear in this report only because they 

are considered essential to the objective of the document.

Quality Assurance Statement—The Federal Highway Administration (FHWA) provides high-quality 

information to serve the Government, industry, and public in a manner that promotes public understanding. Standards and policies are used to ensure and maximize the quality, objectivity, utility, and 

integrity of its information. FHWA periodically reviews quality issues and adjusts its programs and 

processes to ensure continuous quality improvement.

3. Soil and Rock Properties (AFP30) 

Committee (2014), Characterization 

of Bridge Foundations—January 2014 

Workshop (TRB) and Session (TRB) 

Presentations, TRB, Washington, DC, 

accessed on March 24, 2014, https://sites.

google.com/site/trbcommitteeafp30/

characterization-of-bridge-foundations.

4. Butcher, A.P., Powell, J.J.M., and Skinner, 

H.D. (2006), Reuse of Foundations for 

Urban Sites—a Best Practice Handbook,

IHS BRE Press, Bracknell. 

5. Chapman, T.J.P., Anderson, S., and 

Windle, J. (2007), “Reuse of Foundation,” 

Construction Industry Research and 

Information Association (CIRIA).

Publication C653.

6. Highway Division (2013), LRFD Bridge 

Manual—Part I, Chapter 3, LRFD 

Bridge Design Guidelines, MassDOT,

Boston, MA, 2013, http://www.massdot.

state.ma.us/Portals/8/docs/bridge

Manual/2013LRFD/Part%20I/CHAPTER

%203_LRFD_MassDOT.pdf.

7. Indiana Department of Transportation 

and Kentucky Transportation Cabinet 

(2014), Milton-Madison Bridge Project,

accessed on April 15, 2014, http://www.

miltonmadisonbridge.com/ 

8. Simpson, J.B. (2013), Hurricane Deck 

Bridge Demolition, Phase 1, Gallery I, 

LakeExpo.com, Osage Beach, MO, 

accessed on March 26, 2014, http://

lakeexpo.com/lake_events/collection_

ae884ce0-6047-11e3-8fd9-001a4bcf887a.

html?mode=nogs.

9. Structures Design and Bridge 

Management—Geotechnical Section 

(2012), Geotechnical Report, SR-201 

Arthur Mills, Utah Department of 

Transportation, Salt Lake City, UT.