Comparisons of design methods for beam string structure based on reliability and progressive collapse analysis

The current design method of ultimate capacity beam string structure (BSS) is mainly based on the fixed load ratio (FLR) criterion, seldom considers effect random (RLR) bearing capacity. This paper compared coefficient variation (COV) obtained by RLR criterion with that FLR criterion. It indicates properties have a significant impact COV and should be accounted for. A more realistic limit state function built practical simplification, which proved to better accuracy reliability verifications for typical cases. Parametric analyses are also carried out Monte Carlo simulations. results show larger than Thus BSS would overestimated following method, an unsafe resulted in, too. Three targeted indexes selected representative Two improved methods optimum resistance factors according minimum differences between calculated ones among Finally, performance anti-progressive collapse designed two when strut or cable fails. 2 partial factor, varies cases, has collapse.