신뢰성분석을 이용한 화재에 노출된 PSC구조의 확률론적 안전평가

Abstract

Reliability analysis of prestressed concrete structure exposed to fire is conducted by First Order Reliability Method(FORM) to evaluate structural reliability. The evaluation criteria is based on structural reliability and it is following a proposed temperature dependent limit state function. Korea Expressway Corporation standard PSC beams[1] are considered in this study to estimate reliability indices. Korean Bridge Design Specification (Limit State Design, 2012)[2] is used as a design code in this study. Load and resistance parameters are considered as random variables and its statistical parameters are based on the available literature and paper. Dead load, live load and impact load are considered as a load model. Moment capacity is considered as a resistance model and it is function of fire temperature. Heat transfer analysis is performed by ANSYS(2007)[3] solver to determine how internal temperature changes in the section as a function of time. The hydrocarbon fire curve proposed by Eurocode(2004)[4] is subjected to standard PSC beams for 120minutes. The temperature gradient from the finite element heat transfer analysis is applied to the resistance model. The reliability indices from the fire decrease as fire sustainment time goes and it is mainly affected by reduction of material strength.