RELIABILITY ANALYSIS USING FORM AND SORM

Abstract

A comprehensive analysis is presented for the scrutiny of structural reliability with incomplete probability information. The performance of a structure is assessed by its safety, serviceability, and economy. The information about input variables is never certain, precise, and complete. In the presence of uncertainties, the absolute safety of structures is impossible due to the unpredictability of variables involved. In the conventional deterministic and analysis and design methods, it is assumed that all parameters (loads, strengths of materials, etc.) are not subjected to probabilistic variations. The safety factors provided in the existing codes and standards, primarily based on practice, judgment, and experience may not be adequate or economical. This technique is built on the first-order Taylor series approximation of the performance function which is linearized at the mean values of random variables. A better approximation by the second order terms is required for highly non-linear limit states. This is often termed as Second Order Reliability Method (SORM), unlike FORM the expression is considered till second order terms. A beam and column analysis is performed manually as well as with the help of softwares ETABS and COMRELin this project. Beam is analyzed for shear while the column is analyzed for axial force and bi-axial bending. The IS codes failure criteria’s have been used to get to the limiting equations which is then used to calculate the reliability of the components.