Verification of large-diameter bored pile performance using full-scale static loading tests: A case study of the Anhsin bridge foundation of the Taipei MRT

Abstract

Full-scale pile static loading tests provide reliable field verification for large-diameter bored piles supporting long-span bridge structures subjected to extreme axial loads. This study presents a full-scale static loading test conducted for the foundation of the Anhsin Bridge in the Ankeng Light Rail MRT System, New Taipei City, Taiwan. The adoption of an asymmetrical cable-stayed truss-frame system resulted in exceptionally high axial forces concentrated on the main pylon foundation, requiring verification beyond conventional analytical design methods. A 2.0 m diameter cast-in-place bored pile was tested using a hydraulic loading system capable of applying a maximum axial load of 2,881 tons, exceeding both service-level and seismic design demands. The measured load–settlement response was smooth and progressive, with a maximum settlement of 16.67 mm at peak load and a residual settlement of 3.52 mm after unloading, indicating predominantly elastic pile–soil behavior and a safety factor greater than three with respect to service loading. The test results confirm the adequacy and robustness of the foundation design. From a sustainability perspective, the field verification reduced design uncertainty and avoided unnecessary overdesign, thereby supporting efficient material utilization and long-term structural reliability. The findings provide a practical engineering reference for foundation verification in long-span metro bridges subjected to extreme axial loads.