Performance of piled raft foundations subjected to static horizontal loads

Abstract

A series of static loading tests were conducted vertically and horizontally on piled raft models and their components (single piles and rafts alone) on sand by using a geotechnical centrifuge. Much focus was placed on the load-displacement relationship and the load sharing between the piles and the raft in the piled raft system. Effects of the rigidity at pile head connection on the piled raft behavior were also examined. This paper provides basic information on the performance of piled raft foundations subjected to horizontal loads. Principal findings from the present study are: 1) The stiffness and the resistance of the single pile in piled raft foundations are different from those observed in the isolated single piles of the same size, due to the difference in the confining stress condition around the piles; 2) Piles play important roles in increasing horizontal ultimate resistance of piled raft foundations; 3) The initial horizontal stiffness of a piled raft is not always higher than that of a raft (alone) as the piles reduce the contact pressure between raft and soil, and hence the stiffness of the upper soils; 4) Higher horizontal load is transferred to the piles in the piled raft with rigid pile head connection, which leads to higher initial horizontal stiffness compared with that in the piled raft with hinged pile head connection; 5) The proportion of vertical load carried by the piles in a piled raft remains largely unchanged during horizontal loading, while the proportion of horizontal load carried by the piles increases as the horizontal displacement increases.

Numerical analyses of load tests on model foundations in dry sand

“…It is seen from comparison of the figures that the magnitudes of bending moments generated in the front pile P3 are the largest followed by those of the centre pile P2 and by the rear pile P1. Similar behaviours are observed in the experimental study of Horikoshi et al [15]. Although the calculation overestimates the measured bending moments considerably, the calculation simulates well the trends of measured distributions in all piles.…”

“…Experimental studies on piled rafts subjected to vertical loading or combination of vertical and horizontal loading were carried out using centrifuge modelling [15,16], and at 1-g field [17][18][19]. In these experimental studies, behaviours of 2 Â 2-pile piled raft models subjected static or dynamic horizontal loading with vertical loading were investigated.…”

Analysis of Laterally Loaded Piled Raft Foundation

“…In this section a comparison is shown between centrifuge tests data and results by using the proposed method. The numerical analysis has been carried out not as a back-analysis but as a class A prediction, thus using the actual pile and soil properties based on the information and laboratory tests data provided in Horikoshi and Matsumoto (2003) [3].…”

“…Only few experimental experiences and numerical methods [1][2][3][4][5][6][7][8][9][10] for laterally loaded piled raft foundation are available. This results in a lack of enough knowledge about the complex piled raft response under lateral loads.…”

A Centrifuge Model Study on the Effects of Pile Installation Process on Seismic Behavior of Piled Raft Foundation for Oil Storage Tanks

“…A comparison of piled raft, pile group, and raft foundations under static horizontal loadings were made using centrifuge model tests. 10), 11) On the other hand, dynamic centrifuge model tests were also conducted by 12) to compare a piled raft with a pile group foundation and discuss the effect of pile head connection to the raft. In spite of enormous studies on PRFs, optimal and rational design methods of this foundation have not been extended to civil engineering infrastructures.…”