ABSTRACT
This paper describes the research work carried out to investigate the safety of the foundation of a 38floor tower located at the west central part of the Kingdom of Saudi Arabia. Due to variation of bed rock level along the building, the original foundation design was a reinforced concrete raft. Part of this raft rests directly on fresh rock whereas the rest of the raft is supported by variable length rock sockets in the zone where a granular soil exists. Defective behavior of piles was observed from the results of some pile load tests. The main causes of defective behavior causing reduction in geotechnical capacity of bored piles are inadequate geotechnical investigation, degradation of shaft friction, and improper cleaning of base of boreholes (Poulos 2005, Brown 2004, Fleming et al. 1992). (Hemada et al. in press) proposed a procedure for tracing the causes of this defective behavior, and methodology for finite element simulation of the defective behavior of bored piles caused by geotechnical and construction related problems. They proposed to simulate the degradation of shaft friction by controlling the shear strength reduction factor of the interface while the degradation of base resistance is simulated by a tip interface or spring element allowing for softening.
