Piled raft is commonly used as foundation for high rise buildings. The design concept of piled raft foundation is to minimize the number of piles, and to utilize the entire bearing capacity. High axial stresses are therefore, concentrated at the region of connection between the piles and raft. Recently, an alternative technique is proposed to disconnect the piles from the raft in a so called unconnected piled raft (UCPR) foundation, in which a compacted soil layer (cushion) beneath the raft, is usually introduced.  The piles of the new system are considered as reinforcement members for the subsoil rather than as structural members. In the current study, the behavior of unconnected piled rafts systems has been studied numerically by means of 3D Finite Element analysis via ABAQUS software. The numerical analysis was carried out to investigate the effect of thickness and stiffness of the cushion, pile length, stiffness of foundation soil, and stiffness of bearing soil on the performance of the unconnected piled raft. The results indicate that when unconnected piles are used, the axial stress along the pile is significantly reduced e.g. the axial stress at head of unconnected pile is decreased by 37.8% compared with that related to connected pile. It is also found that the stiffness and thickness of the cushion, and stiffness of foundation soil have considerable role on reduction the settlement.

There is a significant challenge to developing the strength and durability of the aerated concrete (AC) for structural applications, but to date, no researchers have focussed on the effect of expanded polystyrene beads (EPS) on the AC properties. EPS-AC consists of cement, sand, water and aluminium powder with commercially available spherical small, hollow and impermeable polystyrene beads. In this research, different contents of EPS from 0 to 4% by cement weight were added to create the AC with different densities. It is revealed that the greatest enhancements in the properties of EPS-AC were noticed when the EPS volume fraction was increased to 4%. The compressive, flexural strength and modulus of rupture were enhanced by 48, 37 and 125% respectively, whereas the density was raised slightly. Moreover, it was shown that all EPS-AC mixes could satisfy the requirements of structural lightweight concrete.

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Piled raft is commonly used as foundation for high rise buildings. The design concept of piled raft foundation is to minimize the number of piles, and to utilize the entire bearing capacity. High axial stresses are therefore, concentrated at the region of connection between the piles and raft. Recently, an alternative technique is proposed to disconnect the piles from the raft in a so called unconnected piled raft foundation UCPR, in which a compacted soil layer (cushion) beneath the raft, is usually introduced. The piles of the new system are considered as reinforcement members for the subsoil. In the current study, the behavior of both connected and unconnected piled rafts systems has been studied experimentally. The effects of different factors, such as; the piles number and configuration, on the load settlement behaviour and pile load sharing are also investigated. The results indicate that when unconnected piles are used, the total settlement of the piled raft system is significantly reduced, and the pile load sharing considerably decrease, e.g., for piled raft with nine piles the total settlement has decreased by 35.6% and pile load sharing has decreased by 20.9%.