ABSTRACT
Seismic behaviour of buildings on liquefiable ground is affected by the size and stiffness of the structural foundation, level of contact pressure, seismic response of the structure and soil, thickness and properties of liquefiable soil layers and non-liquefiable crust, intensity of ground motion and many other factors. Costly ground improvement is commonly carried out to stabilise liquefiable soils. In many cases seismic performance requirements for buildings and structures located on liquefiable sites with a non-liquefiable crust can be satisfied without ground improvement. A foundation system comprising a Reinforced Concrete (RC) raft foundation over liquefiable soils with non-liquefiable crust was designed to support the recently completed Rotorua Police Station building. The adopted design framework included dynamic time-history finite element analysis of soil-foundation-superstructure interaction. Performance based design utilised in the analysis of dynamic soil-foundation-superstructure interaction resulted in substantial cost savings due to avoidance of ground improvement.
