Geotechnical and structural assessment on estimated bearing capacity of strip footing resting on silty sand incorporating moisture content effect

Abstract

This paper aims to assess the ultimate bearing capacity of a strip footing on the ground surface of a silty sand soil layer. It considers structural failures and geotechnical changes, including the impact of moisture content, using numerical simulation in PLAXIS 3D V21. The structural damage assessments on a student center building located in the northern part of Peninsular Malaysia were performed by visual inspection, and thirty-six sub-points of rebound hammer tests were conducted on three selected different points (Point 1, 2, 3) of the building to evaluate concrete strength and record crack characteristics for severity classification. Subsequently, an extensive geotechnical laboratory tests were performed to investigate the effects of moisture content on physical and mechanical properties of silty sand including, soil compositions, Atterberg limits, compaction characteristics and unconfined compressive strength (UCS) from the building area which resulted to structural damage caused by differential settlement beneath the building. The visual inspection assessment has shown the student center building experienced severe damage category at Point 1 with crack width and length are 25 mm and 3 m respectively. At Point 2, there was minimal damage to the surface structure, with a crack measuring 1 mm in diameter and 0.1 m in length. Furthermore, crack width and length are 1 mm and 0.2 m respectively are recorded for Point 3. The study fills in a gap in the research by combining geotechnical and structural tests on the bearing capacity of silty sand with moisture content. The effect of soil saturation, matric suction, and the unsaturated strength of soil are affected by these factors in the analysis of the bearing capacity of the foundation. The exact solution gives us 568.213 kPa for a zero degree of saturation and 385.34 kPa for a 100 percent degree of saturation. The incorporation of geotechnical and structural assessments aims to find reliable strategies for failure remediations for instance patched and sealed with a concrete patching compound.