Comparison of Bearing Capacity of Piled Raft Foundations Consisting of Different Number of Piles under Static and Repetitive Loads

Abstract

In this study, large-scale experiments have been carried out at 5th Regional Research and Development Headquarters Engineering of Highways in order to determine the contribution of the piles in the pile-raft foundation to the bearing capacity. The bearing capacity were determined for only the raft, the raft with single pile and the raft with four pile under static and repetitive loading. In the examinations, sand samples which were taken from a river bed were used. The sand was classified as uniform clean sand (SP) according to standarts.As a result of study following results were obtained. Only raft has reached lowest bearing capacity at different alternatives under static loading. When used single pile and four piles at piled raft foundation systems, the bearing capacity has increased by 1.130 and 2.52 respectively under static loading. As the number of piles increased, it was observed that the settlements at piled raft foundations under the same repetitive loading decrease.

Improving bearing capacity of weak soils: A review

“…The use of a piled raft to minimize settlement of a piled bridge abutment and approach embankment built on soft compressible clay was defined by Reid & Buchanan, (1983) [20] the load was transferred to the pile caps by a "membrane", which spans between the caps of the pile in the catenary. Bağriaçik et al ( 2018) and Banerjee et al (2020) [21,22] carried out studied on pile numbers and pile lengths under the raft subjected to a uniform vertical loading. The settlement aspects for an efficient design of a piled raft subjected to vertical loadings have been addressed.…”

“…The settlement aspects for an efficient design of a piled raft subjected to vertical loadings have been addressed. It is found that the required piled group-raft area ratio (Bg/Br) [21,22] investigated the differential settlement of piled rafts and discovered that settlement increases as the length of the pile is decreased. Therefore, for an effective configuration of piled raft in layered soil, the Bg/Br ratio should be between 0.4 and 0.6, where Bg is the piled area and Br is the raft area [21] .…”