This study aims to develop hazard curves to assess the reliability of shallow foundation design on sandy soils. The random finite element method was employed to analyze the elastoplastic behavior of soils with spatially varying deformation modulus and angle of shearing resistance, which were generated as random fields and assigned to the analysis models. The output distributions were fitted with a corresponding probability density function (PDF), and the probability of exceedance (Pf) for determined damage limits was estimated from these PDFs, forming the proposed hazard curves for the determined anisotropy ratios. The method proposed in the study was validated by a database containing field test measurements, and a sample problem was presented to exemplify the application of hazard curves. The significant contribution of this study is to form the hazard curves for superficial foundations on sandy soils by considering both the elastoplastic behavior of soil and the influence of all effecting parameters, which satisfy the serviceability limits in the foundation design codes. The curves proposed in this study provide an approach for probabilistic investigation of superficial foundations taking the variability of sands into account and robust technique for the reliability-based design of strip footings with a serviceability limit state.

Soil liquefaction-induced damages in buildings and foundation during earthquakes increase the seismic hazard of densely populated urban cities dwelling on young alluvial soil deposits with a rising demand for infrastructural developments. Generally, liquefaction potential is evaluated for specific sites, which lacks the information related to the spatial extent of liquefaction effects. In the present study, liquefaction hazard maps of Kolkata metropolitan city is prepared for potential future earthquakes considering the spatial variability of soil parameters. The importance and application of geostatistical interpolation tools for hazard mapping are highlighted in this paper. Deterministic procedures of Boulanger and Idriss (2004, 2014) were utilized to quantify the liquefaction potential of two types of soil deposits, silty clay and silty sand, in the study area. Probability of liquefaction (PL) was evaluated by first-order second moment (FOSM) reliability method for 2% and 10% probability of exceedance in 50 years. Python codes were developed for the calculation of factor of safety (FS) and PL values for silty sand and silty clay. Spatial distribution maps in terms of FS and PL were generated at 7 m, 15 m and 25 m depth of the study area using ordinary kriging technique in ArcGIS software. The regions of Maidan, Newtown, Rajarhat, Santoshpur, Sector V and Tangra were found to be vulnerable to liquefaction till 15 m depth. Additionally, correlations were also developed between PL and FS using non-linear regression analysis for all soils, silty clay and silty sand of the study area for both the probabilistic scenarios.