The Master’s thesis by researcher Hussein Ali Faisal—conducted at the Department of Civil Engineering, College of Engineering, University of Basrah, under the supervision of Prof. Dr. Mohammed Jawad Kadhim Issa and Dr. Thair Mohammed Saeed—was defended under the title: Effect of Soil-Foundation Interaction on the Reinforced Concrete Multi-Storey Buildings

This study investigates the effect of soil-foundation interaction on reinforced concrete multi-storey buildings using finite element method implemented by PLAXIS 3D (version 24) software.
The thesis is aimed to find out the effect of soil-foundation interaction on the variation of axial force, bending moment, and shear force developed in structural members. The main factors considered in this study are the height of building (number of storeys), span length, type of foundation, and type of soil.
Soil-foundation interaction is evaluated in this study by including five different number of storeys 2, 3, 4, 6, and 9, and three different span lengths 4m, 6m, and 8m. The study also includes different types of soils in selected zones in Basra city, and Missan city, and four different types of foundations raft, strip, isolated, and piled-raft foundations.
The selected case studies have been analyzed under the action of dead loads, live loads, and self weight of the building. It is found when considering soil-foundation interaction, the axial forces have increased by about 94% in corner columns and about 21.8% in edge columns, and decreased by about 16.4% in interior columns. The negative moments have varied up to 388% in exterior beams and 222% in interior beams, and the positive moment have varied up to 71% in exterior beams and 50% in interior beams. The shear forces have varied up to 151% in exterior beams and 87% in interior beams.
It is concluded that the axial force, bending moment, shear force developed in structural members of the reinforced concrete multi-storey buildings are highly affected by considering soil-foundation interaction compared to those in buildings with fixed ends at base.