Development of optimum design from static response of pile–raft interaction

Abstract

Piled raft foundations are among the most commonly used support structures for offshore projects. When a raft foundation alone does not satisfy the design requirements, piles may be added to improve the ultimate load capacity and the settlement performance of the raft. In this study, design criteria were developed for the undrained behavior of a piled raft system based on an examination of average and differential settlements, raft bending moment, and pile butt load ratio. Raft settlements were evaluated by a series of three-dimensional finite element analyses. The average settlement values for the piled raft were highly influenced by the number of piles and the raft thickness. Optimal design configurations of piles for cohesive soils are discussed. Increasing the pile spacing decreased the pile butt load ratio by allowing for a more uniform load distribution between the piles.

Numerical analysis of settlement and bearing behaviour of piled raft in Babol clay

“…In such cases, the optimisation of piled rafts should be performed using varying pile lengths and arrangements according to the subjected load type in order to reduce the interaction among equal-length piles and improve the overall foundation performance. Some previous researches have been devoted to optimise the design of piled rafts by varying pile size and pile configuration including Horikoshi and Randolph (1996), Kim et al (2001), Leung, Klar, and Soga (2010), Nguyen et al (2014) and Taghavi Ghalesari, Barari, Fardad Amini, and Ibsen (2015). Nevertheless, a few studies have considered a combined pile size and arrangement optimisation.…”

Numerical Analysis of the Response of Pile-Raft Systems Considering the Application of Cement and Polypropylene Fiber Treatment

“…The degrees of freedom on lateral planes were blocked of moving in a perpendicular direction to these surfaces and the base of the model was constrained against translation in three directions. Based on the previous studies, the depth of the model was assumed to be more than twice the pile length [26,27] and the lateral boundaries were considered to be more than the raft breadth [28]. The in-situ condition was simulated by producing the geostatic stresses in the first stage of loading.…”

Machinery/Service system Scheduled Replacement time determination: A combine Weighted Aggregated Sum Product Assessment, Additive Ratio Assessment and Age Replacement Model approach

“…The concentration of finite element mesh near the stone columns is higher than that in farther distances to acquire better accuracy. The connection of the stone columns and the encasement as well as the connection of the encasement and the surrounding soil was modeled by interface elements (as described in Taghavi Ghalesari et al [16,17]) with the strength reduction coefficients of 0.7 and 0.8, respectively. The depth of the soil was assumed to be 20 m and the width of the model was considered to be dependent on the breadth of the foundation to diminish the effect of the boundary on the response.…”