The Effect of 3D Interference of Shallow Foundation on Settlement and Its Impacts on Building Structures

Large differential settlement beneath buildings results in severe damages that can compromise building integrity. Many factors affect building settlement including soil characteristics, ground water table, seismic activities, exitance of sinkholes, poorly compacted soil and out-engineered adjacent excavation activities. This paper examines the effect of building height, soil characteristics, tie beams and interference among the shallow foundation on total and differential settlements. Furthermore, it examines the effect of excessive differential settlement on building structure. Three buildings with 3-, 6-and 9-stories having the same square plan with a side of 24 m are initially designed under gravitational loads without considering any settlement. Four different soil profiles are considered under each building, namely strong soil, strong over weak soil, weak soil and weak over strong soil. Two different types of shallow foundations were designed for each building; the first as isolated footings connected with tie beams and the other case without tie beams. The buildings have been modeled using ETABS for conducting the structural design of different buildings’ components. Then soil settlements were determined using Plaxis 3D finite element analyses. The analysis reveals that the interference among building footings has a significant impact on total and differential settlements.