Hazard Curves for Reliability Assessment of Strip Footings on Spatially Varying Cohesive Soils

Abstract

The present study aimed to create a series of hazard curves against maximum total settlement and angular rotation of strip footings for probabilistic shallow foundation design on clays. Random field finite element method (RFEM) was adopted with elasto-plastic clay-like soil behavior, deformation modulus (Ed) and shear strength parameters (c and ) were employed as random field inputs. Parameters were defined and assigned to the analysis models with varying correlation lengths (h, v). Models have been iteratively solved one thousand times, and output distributions of maximum settlement and angular rotations were recorded. Probability density functions (PDF) were fitted to the outputs, and probability of failure (Pf) for footing deformation limits was subsequently estimated. Proposed hazard curves for two anisotropy and three variability categories were developed employing the estimated Pfs. The method proposed has been validated using an independent database of in-situ results, and a worked example was provided to illustrate the implementation of the process. The key contribution of the research is to form hazard curves for shallow foundations considering elasto-plastic soil behavior with the impact of all influencing parameters, respecting the limit values for foundation deformation in the design codes. The proposed technique offers a probabilistic evaluation of strip footings with spatial variation of clayey soils and a valid method for the reliability-based design of foundations in the serviceability limit state.

Keywords

• Random field finite element method
• strip footings
• soil-foundation-structure interaction
• reliability-based design
• serviceability limit state
• cohesive soils

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