Development of FEA models to predict the behavior of steel bridge piles strengthened with FRP jackets and grout
Griggs, David M.
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Corrosion of the steel compression members used as bridge piles reduces the axial load carrying capacity significantly. To combat this, the Texas Department of Transportation (TxDOT) initiated a research project to develop cost-effective, yet reliable methods to repair/strengthen the corrosion-damaged bridge steel piles. This study was performed as part of the TxDOT project with focus on the development of finite element (FE) models that can be used to predict the behavior of un-damaged, damaged, and repaired steel piles. Many potential repair methods were proposed in the TxDOT project. Among them, this study focused on a method which uses a fiber reinforced polymer (FRP) jacket to surround the damaged area and is then grouted into place. A series of FE models were created to duplicate existing laboratory test specimens. The analysis results of the FE models were then compared to the experimental results to evaluate the performance of the developed FE models. The performance evaluation showed that the FE models could predict the failure loads with the error ranging from 1% to 27%. Based on the knowledge built on the performance evaluation of the developed FE models, a series of FE models were developed and analyzed to make recommendations to the design of laboratory test specimens (60 in.-long W4X14 sections) of the on-going TxDOT project, which include the location and size of corrosion damage, and the strengthening details such as the number of FRP layers and size of the FRP jackets. The FE models developed in this study assumed that there is the 'perfect bond' between the steel members and grout. Although the FE models have shown good agreement with the experimental results, it is recommended using a shear stress - slip model to simulate the steel-grout interface behavior to further improve the accuracy of the developed FE models.