ABSTRACT

This research was conducted to observe behavior of 3.0 m x 3.0 m large scale model of Short Piled Raft foundation system on peat soil during loading test. The sequence of loading test consists of loading - unloading - reloading - remain - unloading, from 0 kN - 100 kN (100% design load) - 0 kN - 160 kN (160% design load) - remain for 24 hours - 0 kN, with increment or decrement of 20 kN. Five locations were observed, one at the centre and four others at each corner. After conducting the test under the load of 100 kN, 160 kN and remain of 160 kN for 24 hours, it can be seen that the maximum of total settlement ST(max) occurs at the center [CR], each is 7.80 mm, 29.90 mm and 36.20 mm respectively. While the maximum of difference in total settlement between any two points ∆ST(max) is 1.95 mm ([SW] – [NE]), 10.30 mm ([SW] – [SE]) and 9.65 mm ([SW] – [SE]), under the load of 100 kN, 160 kN and remain of 160 kN for 24 hours respectively. The ST(max) occurs at the centre is easily understood, because the load is acting on it. Differential settlement may occur, because peat soil underneath the foundation is not homogeneous, thus, response of piles to contribute supporting load may also be different, and finally produce differential settlement. It can also be seen that the pile can function as stiffener of concrete slab effectively. The tolerable settlement is ST(max) < 50 mm and ∆ST(max) < 20 mm, therefore it can be concluded that ST(max) and ∆ST(max) which occur are tolerable.

Keywords: Differential settlement, Total settlement, Loading test, Short piled raft, Peat soil