Time-dependent reliability of existing RC structures

The conditional probability of failure of a structure, given that it has already survived for T years, shows that structural reliability increases for service proven structures. Further, construction loads act essentially as proof loads, and so provide a means to detect the presence of gross construction errors. The present paper investigates the effect of construction error, proof load tests prior to occupation, realistic construction loads, and dead loads and office floor live loads on the probability of failure of service proven structures. The human reliability analysis (HRA) approach is used to simulate the effects of construction error. Results obtained from a Monte-Carlo computer simulation analysis showed that up to 50% of failures will occur during construction for reinforced-concrete beams constructed without engineering inspections. This suggests that construction loads act essentially as proof loads; hence, for structures with low live-to-dead load ratios the adverse consequences of construction error will most likely become evident during construction. Nevertheless, engineering inspections is a more effective error control measure.