Testing and assessment of FRP strengthened concrete T-beam bridges in Pennsylvania

Abstract

It is increasingly becoming of great concern that the transportation infrastructure is in poor condition and in need of rehabilitation. Reinforced concrete (RC) structures such as bridges are a prime example for displaying rehabilitation needs. Harsh environmental conditions and age, along with the use of deicing salts in the winter seasons, greatly increase deterioration rates. Addressing bridge conditions in an effective manner and ensuring the safety of the public is a challenge for engineers and owners. The Pennsylvania Department of Transportation-District 3 (PennDOT-D3) initiated a program to address the condition of their concrete T-Beam bridges. 128 concrete T-Beam bridges constructed between 1920 and 1960 are included in the district's bridge inventory. Many of these bridges have become structurally deficient or obsolete due to aging and deterioration. PennDOT-D3 paired with West Virginia University researchers to develop a program that would use FRP rehabilitation technology to repair and strengthen its large number of concrete T-Beam bridges. The work presented in this thesis focuses on the third phase of a three-phase project concerning the rehabilitation of bridge #49-4012-0250-1032 built in 1934 near Sunbury, Pennsylvania. Quality control and assurance was performed with several field visits during the construction process. Load testing was performed to replicate the load testing performed prior to rehabilitation in Phase II of the project. Data resulting from load tests before and after rehabilitation was compared. An FE model of the bridge was developed and calibrated using field testing data and inspection. The FE model was subjected to the same loading conditions as applied in the field and also compared for a more thorough structural evaluation. The FE model was also subjected to AASHTO standard live loading conditions to investigate current load rating methods for these types of structures. Discrepancies resulting from accurate FE analyses when compared to simplified methods of analysis are discussed. Based on existing literature and knowledge gained throughout the project, design, construction, and testing/long-term monitoring guidelines were drafted in PennDOT-D3 desired formats. These guidelines are considered important outcomes for Phase III of the project and for the development of this thesis. The guidelines were developed for incorporation into PennDOT standard documentation for the successful transfer of knowledge concerning the FRP repair technology. With the design guidelines, an FRP design program was created specifically for simple span concrete T-Beam bridges. The design program is user friendly and allows for detailed input based on field inspection. The program gives structural capacities for the original, existing, and strengthened conditions of primary bridge members. Load rating factors are also presented for the existing and strengthened T-Beam analysis.