Assessment of the performance of spread footings and mat foundations on expansive soils

Abstract

This paper presents two real case buildings that are redesigned considering the heave of the ground formation. The buildings are evaluated for upward swelling pressure, taking into account dead load, live load, and expansive soil load combinations. The criterion used to evaluate the safety of buildings constructed on expansive soils is first presented. Then, two scenarios regarding soil wetting are examined. In the first scenario, water only reaches the perimeter of the building, causing soil expansion at the outer boundaries. In this case, swelling pressure is only applied to the outer parts of the buildings. In the second scenario, heave occurs beneath the interior part of the building due to leakage from the domestic supply network. The structural integrity of the two buildings is evaluated by observing angular distortion at varying levels of swelling pressure. This assessment aims to determine to what extent the use of traditional foundation systems (spread footing and mat foundation) is feasible to support buildings on expansive soils considering different levels of swelling pressure. The study focuses on performing a detailed structural analysis of the building using the ETABS. The findings of this study have important implications for the design and construction practices in semi-arid regions.

Keywords

• Collapse
• Structural analysis
• Spread foundations
• Mat foundation
• ETABS