A Case Study on the Bearing Capacity of Large Diameter Bored Piles Plugged in Weathered Limestone for Cable-Stayed Bridge

For bridge projects, load testing for large-diameter bored piles in the middle of a river is a challenge for traditional static load testing methods. The Bi-directional Static Axial Compressive Load—BSACL (ASTM D8169-18) solution is a reasonable method with the advantages of not using weight load and faster progress. This article presents the results of BSACL for a 1500 mm diameter bored pile, 45.5 m long, with the pile tip embedded in a weathered limestone layer. This is a case study of the Hieu River cable-stayed bridge in the center of Vietnam with a 200 m length span. The maximum load reached 17,250 kN applied through a Load Box placed at a depth of −37.4 m, with a movement of the Load Box approximately 11.9 mm upward, 9.8 mm downward, and 6.3 mm at the pile head. The side resistance in the slightly weathered limestone layer (RQD = 30%) achieved 350 kPa, and in the highly weathered limestone layer reached 175 kPa (RQD = 0%). The side resistance of the soil layers above the Load Box is also analyzed through strain gages simultaneously. The research results could help engineers to understand the load distribution along the bored piles.