Reliability assessment of existing building structures based on target period of usage

Based on the probability models of load and resistance for existing building structures, this paper brings forward practical evaluation methods to assess the reliability of structural members. Besides, an applicable method to assess the reliability of existing building structural systems based on minor structures is proposed, in which the weights of different structural members need to be considered. In the method, the reliability of minor structures, usually they are taken as natural stories of the structure, is assessed first, and the reliability of the structural system is then evaluated according the assessing results of minor structures and the relationship among minor structures in the structural system. Through analysis of comparison, a concise method to determine the weight coefficients of structural members in a minor structure is developed. Research results presented in this paper have been used in the first version of Engineering Construction Code for Shanghai in China: Standard of Structural Inspection and Assessment for Existing Buildings.