Behaviour of tall building subjected to multiphase contact between foundation and subgrade

The contact problem under the foundation of tall buildingssupported on strip or mat foundation and resting directly on the elastic soilmedium has received considerable attention in recent years. Settlement ofthe supporting soil under the foundation of an existing building can becaused by several factors. Although, the contact problem between thefoundation of the structure and its supporting soil is non-linear problem,the settlement of the supporting soil under the foundation of an existingbuilding change the problem to a highly complicated one, since the twotypes of unbonded contact conformal and non-conformal are existing at thesame time. The contact problem in this case is called as multi-phasecontact problem.However, many computational models have been developed forconfonnal and non-conformal contact problems, but nothing is developedfor the multi-phase contact problem which constitute both confonnal andnon-conformal contact regions.An incremental computational model is developed which is capableof dealing with the contact problem between the foundation of the buildingand the supporting soil as elasto-plastic multi-phase contact problemcontains both types of contact conformal and non-conformal at the sametime. The developed model exploits the convex programming method inthe frame work of the finite element scheme. The proposed model takesinto consideration the elasto-plastic behaviour of the superstructure and thenon-linear behaviour of the supporting soil at the contact surface. Thedeveloped model dose not need the insertion of any special artificialelements (Gap element ) and it could be appended easily to any finiteelement code.The developed model is exploited for the construction of two elasto-plastic computer systems for the two and three dimensional analysis oftall-buildings consists of a series of frames and shear walls. Thesebuildings are assumed to be supported on strip or raft foundation andresting on elastic soil media. The computer systems considering the soilstructure interaction problem of these buildings as multi-phase contactproblem contains both types of contact conformal and non-conformal at