Reliability Analysis of Spread Footing Over Circular Void

Abstract

Presence of void beneath the footing affects the stability itself and causes severe damage to the structure. The stability of footing depends on condition of operating it and the properties of soil, voids. Existence of underground cavities for important and huge structures such as pipe lines and tunnels affects its serviceability. The factors affecting the Bearing capacity and settlement of footing are soil properties, operational conditions, void size, location of void, number of voids and depth of foundation. The performance of footing is analysed over void under different boundary conditions using finite element package PLAXIS 8.1 version. The data used in the present study is taken from available literature. On the other hand, though deterministic analysis gives basic idea, probability of failure of the structure is analysed using reliability method. For this purpose linear response surface model is generated using two-level full factorial design and limit state function is obtained. Reliability analysis is performed on the footing with voids by using first order reliability method (FORM). The probability of failure of structure under standard conditions is analysed and requirement of reliability is discussed.