Mohammad Sadegh Barkhordari - Ph.D. student, Department of Civil and Environmental Engineering, Amirkabir University of Technology, Tehran, Iran,
Mohsen Tehranizadeh. - Professor, Department of Civil and Environmental Engineering, Amirkabir University of Technology, Tehran, Iran,

Base level is one of the important parameters in determining the seismic force and preliminary design of structural sections. According to the 2800 standard, code of practice for seismic resistant design of buildings, the base level refers to the level at which it is assumed that the horizontal movement of the ground is transmitted to the structure. Although there are many factors affecting the location of base, for typical building without a basement the base is generally considered near the ground level. In structures, due to strong forces and moments at the foot of the structure, examining the location of base level and its movement becomes specially important. The aim of this study was to investigate the impact of changing the properties of the soil around the underground perimeter walls on the base level, taking into account the effects of soil-structure interaction systems. In this regard, the soil-structure system was investigated in two-dimensional models and the location of base level was identified using shear and drift changes. The results indicated that taking into account the level of the upper stories is possible through, performing appropriate walls integrated with the structure even without Compacting the soil around the structure.

base level, trussed tube system, soil-structure interaction, near field earthquake, finite elements