This report presents the results of a research program aimed at investigating the constructability and effectiveness of externally bonded fiber reinforced polymer (FRP) strengthening systems for improving the flexural capacity of bridge decks and piers. The joint effort of two universities, industry, and a state department of transportation provided the premise for a successful outcome. Bridge J857 was constructed in 1932 and was scheduled for demolition in the fall of 1998 due to highway realignment. Two of the three solid reinforced concrete (RC) decks were strengthened using two FRP systems, namely, near-surface mounted carbon FRP (CFRP) rods and surface bonded CRFP sheets. Bridge decks were tested to failure under quasi-static loading cycles. Flexural strengthening of bridge columns was achieved by mounting CFRP rods on two opposite sides of the columns. Columns were also jacketed with carbon and glass FRP laminates. The experimental moment capacities of the decks compared well with theoretical values. Strengthened decks exhibited ductile behavior prior to FRP failure. The columns were tested to failure by applying lateral load cycles. The proposed strengthening technique for the bridge columns is feasible and effective for improving the flexural capacity of RC columns. The capacity of the strengthened column sections could be predicted using classical methods of analysis. Dynamic tests were conducted on the deck strengthened with CFRP sheets. The objective of dynamic tests was to relate the change in fundamental frequency to the induced damage, which could be used as a tool to assess the damage level of RC structural members. An effective damage indicator was identified that requires no baseline for damage level detection. The final report consists of three volumes. This volume, Volume II, focuses on a feasibility study on damage detection by the dynamic testing. The experimental work in the field is backed by laboratory testing for conceptual verification for the assessment method. Test results are presented and compared with theoretical predictions. Conclusions regarding the use of dynamic testing for structural assessment are presented. This volume also includes a summary of the elastic field-testing system as well as the elastic test results of the middle deck of the bridge. Conclusions are made on the effect of bridge accessories and boundary conditions on the continuity of deck slabs.
[1]
Z. Bažant,et al.
Deformation of Progressively Cracking Reinforced Concrete Beams
,
1984
.
[2]
Antonio Nanni,et al.
Strengthening of bridge G-270 with externally bonded CFRP sheets
,
1999
.
[3]
John T. DeWolf,et al.
Experimental Study of Bridge Monitoring Technique
,
1990
.
[4]
O. S. Salawu.
Detection of structural damage through changes in frequency: a review
,
1997
.
[5]
Ahmet E. Aktan,et al.
MODAL TESTING FOR STRUCTURAL IDENTIFICATION AND CONDITION ASSESSMENT OF CONSTRUCTED FACILITIES
,
2001
.
[6]
Charles R. Farrar,et al.
Damage identification and health monitoring of structural and mechanical systems from changes in their vibration characteristics: A literature review
,
1996
.
[7]
O. S. Salawu.
Non-destructive evaluation of constructed facilities using vibration testing
,
1994
.
[8]
Robert D. Adams,et al.
Vibration Testing as a Nondestructive Test Tool for Composite Materials
,
1975
.
[9]
John M. Biggs,et al.
Introduction to Structural Dynamics
,
1964
.
[10]
O. S. Salawu,et al.
BRIDGE ASSESSMENT USING FORCED-VIBRATION TESTING
,
1995
.
[11]
Mahmod M. Samman,et al.
VIBRATION TESTING FOR NONDESTRUCTIVE EVALUATION OF BRIDGES. I: THEORY
,
1994
.
[12]
D. R. Sanders,et al.
Nondestructive evaluation of damage in composite structures using modal parameters
,
1992
.
[13]
Masoud Sanayei,et al.
Damage assessment of structures using static test data
,
1991
.
[14]
Fu-Kuo Chang,et al.
Structural Health Monitoring: Current Status and Perspectives
,
1998
.
[15]
George C. Yao,et al.
Damage diagnosis of steel frames using vibrational signature analysis
,
1992
.