Settlement Profile and Pile Load Distribution Under Vertical Load of Piled Raft Foundation in Clay
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ORIGINAL PAPER
Settlement Profile and Pile Load Distribution Under Vertical Load of Piled Raft Foundation in Clay Ningombam Thoiba Singh
. Baleshwar Singh
Received: 18 March 2017 / Accepted: 13 May 2020 Ó Springer Nature Switzerland AG 2020
Abstract In the rigorous analysis using FEM, the load sharing of the piles between the shaft and base resistance increased with increase in limited number of piles i.e. limited to decrease in pile spacing. The load sharing depends upon their location and spacing. The load carried by the center pile reduces with the increase in the number of piles and piled area. For the edge piles, it increased with the increase in the number of piles, whereas decreased for the corner piles. The total load carrying capacity of the piles increased with the pile sizes and spacing. The piled raft settlement decreases with the increase in the number of piles. By rearranging the same number of piles, more settlement of piled raft is observed for less pile spacing, which concentrated at the center, and the settlement is decreased with increase in pile spacing, which scattered outwards. Increased in number of piles is not always advisable and expensive. Based on limitation in settlement as specified by the code, limited number of piles and pile spacing are recommended. The settlement profile along the centre line of the piled raft
N. T. Singh (&) Dept. of Civil Engineering, Assam Don Bosco University, Guwahati, India e-mail: [email protected]; [email protected] B. Singh Dept. of Civil Engineering, Indian Institute of Technology, Guwahati, India e-mail: [email protected]
decreased with the increase in the number of piles and more flexible at larger pile spacing. Keywords Load sharing Elastic–plastic Piled raft Settlement Settlement profile
1 Introduction Providing piled raft foundation in clay is considered economic and safest foundation system for multistoreyed buildings or loaded structure. The piles may be used for settlement reducing or load bearing whereas the load is being considered uniformly distributed through the raft. The major concerned for the design of piled raft is the relative proportions of the load carried by the piles & the raft and their differential settlement. The concept of the piled-raft foundation is to transfer the load from the building or structure through its lower structure raft then to the existing soil through piles. The fraction of the load transferred to the raft plays an important role in the design procedure. It is assumed that during deformation, the excess load from the pile being transferred to the raft slab leads to a pressure distribution under the raft. Of course, the settlement of the piled raft foundation may be higher than the fully piled foundation, but it must be within the permissible limit as specified by the buildings code (Fig.1).
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Geotech Geol Eng
Fig.1 Concept of piled raft foundation
An optimum piled raft design for various pile configurations was discussed
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