Performance Evaluation of Reinforced Concrete Piled Raft and Pile Cap Foundation Systems through Full-Scale Field Testing

Abstract

The use of foundation systems on clayey soils poses serious challenges due to their low shear strength and high compressibility, making the need for appropriate sustainable foundation systems necessary. This study analyzed the structural capacity and the material effectiveness of reinforced concrete piled raft and pile cap foundation systems through full-scale field tests. Tests were carried out using reinforced concrete piles with a square cross-sectional size of 30 cm × 30 cm, and lengths ranging from 8–12 m, along with a reinforced concrete raft fabricated through C30 concrete. The tests were carried out based on the ASTM D1143 method to test the load-settlement relationship and the load-sharing mechanism. The results revealed that the piled raft foundation system performed better in terms of load-bearing capacity and settlements than the conventional pile cap foundation system. For instance, the four-pile piled raft system had a maximum load-carrying capacity of 300–310 kN, which is about 20% higher than the pile cap system with a load-carrying capacity of 250 kN. In the same way, the two-pile system had a maximum load-carrying capacity of 225 kN, and settlements were lower. Raft–pile–soil interaction facilitated the efficiency of load sharing and minimization of the use of extra piles. The research is an important contribution to the development of sustainable foundation engineering as it provides practical evidence through experimentation that pile raft foundations can improve the performance of structures while minimizing the use of construction materials. The results will assist engineers in designing optimum reinforced concrete foundations in clay soils.