Case study of a piled raft foundation constructed using a reverse construction method and its post-analysis

Abstract

A building and its foundation were constructed in sandy ground using a reverse construction method. The main difference between a reverse construction method and a conventional construction method is that the piles are cast in place and are partially loaded by the superstructure early during the construction process. It is only later that the raft (mat foundation) is constructed to combine with the piles to bear the full building load. Therefore, the foundation is regarded as a pile group in early stages of construction, while the foundation behaves as a piled raft after completion of the raft construction. A simple conservative design approach was used for the design of the foundation. To examine the validity of the design method, settlements of the foundation were observed during construction. The measured settlements were smaller than those predicted in the design stage, satisfying the design requirements for the building. Post-analysis of the deformation of the foundation was carried out using the results of the pile load test at the construction site, and the results of the analysis are compared with the observed settlements of the foundation, aiming at an improvement in pile foundation design.