Graduation Semester and Year

2018

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Civil Engineering

Department

Civil Engineering

First Advisor

Nur Yazdani

Abstract

Deterioration of aging highway bridges has been a serious concern in the U. S. A. Almost 39% percent of all bridges in the country have passed their 50-year design life, and approximately 9% of these bridges are structurally deficient due to concrete deterioration and truck weight increases on highways. Compared to superstructures, the deterioration of bridge substructures and associated repair/strengthening/evaluation has received much less attention in previous studies. A reinforced concrete bridge built in 1940 and located in Dallas, Texas, exhibited moderate to severe corrosion related concrete deterioration in the bent caps. Eight such bent caps were selected herein for repair, carbon FRP (CFRP) strengthening for strength gain and confinement, long-term durability, and evaluation. The in-situ performance of the carbon FRP (CFRP) system of bent cap strengthening was evaluated through full-scale load testing. The investigation consisted of three phases: static load testing of deteriorated bent caps before repair and CFRP strengthening, repair/strengthening of the bent caps using an epoxy mortar and longitudinal/transverse CFRP laminates, and follow-up load testing after CFRP repair/strengthening. Test data comparison showed a reduction in the live load strains ranged from 20 to 28% due to a contribution of the CFRP and concrete repair on the strength and stiffness of the bent caps. Numerical models were performed to investigate the flexural behavior of the bridge in the undamaged, damaged, and repaired states. The bent caps after being repaired show that the flexural capacity of the damaged bent caps has been improved.

Keywords

Bent caps, FRP composites, Load testing, Repair, FE model

Disciplines

Civil and Environmental Engineering | Civil Engineering | Engineering

Comments

Degree granted by The University of Texas at Arlington

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