PSI - Issue 47

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Nurul Najiha Imam Robit et al. / Procedia Structural Integrity 47 (2023) 597–601 Author name / Structural Integrity Procedia 00 (2019) 000–000

© 2023 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the IGF27 chairpersons Keywords: moisture content; structural crack ; silty sand soil ; shallow foundation ; bearing capacity failure ; settlement 1. Introduction It is often unavoidable for cracks to form in structural elements and other parts of a building, such as walls and columns. Thus, some common practices define the maximum permissible width of cracks, depending on the nature and conditions of exposure of a structure. The presence of structural crack can be caused by differential settlement underneath the foundation of the structure that allow water to penetrate the soil, resulting in bearing capacity failure. The amount of water present in a soil mass is known moisture content, and its effect will reduce the soil strength and stiffness but increase the compressibility of soil when fully saturated with water. The bearing capacity of soil is reduced when moisture content is high in wet condition because soil particles lose cohesion while low moisture content in dry condition resulting in bearing capacity reduction due to lose bonding between soil particles. The effect of moisture content variation in dry and wet conditions for fully saturated (degree of saturation, Sr = 100%) and unsaturated soils (degree of saturation, Sr = 0%) on the properties of soil ground and the whole building cause soil deformation and differential settlement, which is mostly neglected in assessing the structure lifespan performance. Thus, this study aims to investigate the effect of moisture content variation on bearing capacity of strip footing on silty sand from non destructive test data information. The numerical analysis of bearing capacity failure of soil under the influence of moisture content in saturation effect was validated with numerical and analytical from past studies. Nomenclature B width of footing Sr degree of saturation 1.1. Structural Integrity of Geotechnical Foundation The structural integrity of a building or foundation depends on the interaction between the structural unit on top of soil underlying the structure. Bearing capacity of soil is the ability of the soil to support loads without fail in shear, resulting to excessive deformation or settlement. There are few factors contribute to shear failure in soil, for instance, stiffness of the foundation–subsoil system and compressive strength of concrete (Boni ć et al., 2022). Many past studies were carried out to estimate the ultimate bearing capacity of soil by analytical (Serrano et al., 2015), experimental (Ahmadi & Hajialilue-Bonab, 2012) and numerical approaches (Nujid, 2018, Griffiths, 1982, Nujid & Taha, 2014, Md Nujid & Taha, 2014) under geotechnical characteristics of soils and structural properties of footing. However, a problem related to structural and geotechnical interaction has caught less attention, and most commonly problem related to building’s performance such as crack formation due to angular distortion and differential settlement are understudied. 1.2. Bearing Capacity of Geotechnical Foundation The variation of moisture content effect in both conditions of soil lead to bearing capacity failure. Raszczuk and Karolak (2021) found that the main causes of the walls and vaults crack on historic church in Poland were due to differentiated soil and water conditions beneath the building. Ngugi et al. (2021) stated as moisture content increase, soil deformation occurred, and footing will experience differential settlement from the changes in shear forces, bending moments, compressive and tensile stresses. The soil strength also decreases as moisture content increase (Jan & Marian, 2020). Shams et al. (2018) had incorporated soil suction and moisture changes on stiffened slab foundations on reactive soils using coupled flow-deformation and stress analyses in three-dimensional hydro-mechanical finite element model. © 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the IGF27 chairpersons