TRANSITION FROM ASD TO LRFD: A COMPREHENSIVE REVIEW OF GEOTECHNICAL DESIGN METHODS, THEIR EVOLUTION, CHALLENGES AND FUTURE SCOPES

Abstract

This research paper presents a comparative analysis of various geotechnical design methodologies, including Limit Equilibrium Method (LEM), Limit State Method (LSM), Allowable Stress Design (ASD), Ultimate Limit State (ULS), and Load and Resistance Factor Design (LRFD). The study explores their fundamental equations, assumptions, and factors affecting bearing capacity calculations for shallow foundations. A parametric analysis is conducted using predefined soil and foundation parameters to evaluate the conservatism, reliability, and efficiency of each method. The results highlight the strengths and limitations of deterministic versus probabilistic approaches, emphasizing LRFD as a robust methodology for modern geotechnical engineering due to its ability to explicitly consider uncertainties in load and resistance factors. The study provides insights into the suitability of different methods for various geotechnical applications and contributes to the ongoing discourse on improving geotechnical design standards.