Efficiency of Strengthening the Sab Takian Canal Bridge Using Shotcrete and Post Tensioning

Abstract

The Sab Takian Canal Bridge on Highway 2247 (ChongkoLam Som Phung), located at km 11+521, experiences heavy traffic from freight transport, leading to deterioration over its long period of service. To address this issue, the Department of Highways has undertaken structural reinforcement by expanding the bridge’s cross-sectional area (RC-Jacketing) in the compression zone. This involves thickening the underside of the bridge deck using shotcrete and reinforcing the tensile zone with external post-tensioning wires installed beneath the supporting beams. These measures aim to enhance the bridge’s load-bearing capacity. This research aims to evaluate the load-carrying efficiency of the Sab Takian Canal Bridge before and after the reinforcement by assessing the safety rating factor (RF) according to AASHTO LRFR standards. The study involves selecting an appropriate bridge segment for a simulated live load test. During the test, sensors are installed to measure vibration, deflection, and strain. The data collected are then used to refine a three-dimensional finite element analysis (FEA) model of the bridge. The safety rating factors (RF) before and after reinforcement are compared to determine the effectiveness of the methods applied. The findings reveal that the reinforcement techniques thickening the compression zone and applying external post-tensioning in the tensile zone significantly improve the safety rating factor. Additionally, reductions in strain and deflection values in the concrete deck and beams demonstrate that these reinforcement methods effectively enhance the bridge’s load-bearing capacity.