3D Dynamic Finite Element Analyses and 1 g Shaking Table Tests on Seismic Performance of Connected and Nonconnected Piled Raft Foundations

Abstract

Connected and disconnected piled raft foundations have been evaluated under lateral cyclic loading in this study. Connected Piled Raft (CPR) and nonconnected piled (NPR) foundations were considered and evaluated in 1-g shaking table tests. FEM numerical modelling also was employed to evaluate the results. The responses were evaluated and compared using lateral movement of caps, moments and lateral loads along the piles and ground settlements. The results indicate that both nonconnected and connected piled raft foundations effectively reduce the ground settlements, however, connected piled rafts have much higher lateral stiffness and piles contribute to lateral load bearing mechanism more effectively; in connected piled raft, piles bear higher moments and lateral loads and reduce lateral movements more effectively. The cap weight and superstructure (central mass height) effect has been considered through supplementary numerical assessments for CPR case. Superstructure addition tends to increase the pile moment and raft inclination where the frequency effect is also critically important. Also heavier cap experiences higher rotations and associated with higher induced loads to piles.