Studying of the Effect of Soil Settlement under Different Types of Footings on Multistory Buildings

Abstract

The aim of this paper isto study the effect of soil settlement under different types of footings for multistory Buildings. Soil settlement sometimes occurs under the foundations due to bad soil compaction, water pipe leakage, soil erosion and excavation on neighboring site. Also the similar effectmight occur due to columns damages happened by explosion. Settlement effect on the moment and shear in beams and footing was studied. Also the effect of columns load and maximum base pressure under footing was studied. Building with dimensions 16*16 meters with four spans in both ways was assumed for studing in this paper, the building has three stories. Software STAAD.ProV8i was used in the analysis, finite elements are used to represent the slabs and footings. The soil subgrade reaction was used to represent soil in software. Four types of footings were taken in this study which are spread footing, spread footing with tie beam, contineous footing and raft footing. Two settlement positions in the building was studied, the first one is under the internal footing and the second one is under exterior footings. The effect of tie beam dimension increasement and settlement in part of spread footing were studied also. The study clearly show that, the continuous footing is a very good selection because it shows a very good response against settlement, keep the settlement within allowed values and has lower cost than the raft footing. The study recommends to avoid using spread footing with or without tie beam. Tie beam dimension increasement has little effect to improve spread footing. Also,the study recommends suitable values of additional saftey factors for column and beam design when settlement is expected.

Keywords

• soil settlement
• footing
• multistory building
• subgrade reaction