Stochastic load exceedances with general material nonlinearity

Reliability of a structural member with nonlinear material property subjected to floor live-load processes is investigated. Earlier studies have assumed a bilinear load-deformation relationship. How- I ever, the actual force-deformation relationship exhibits a nonlinear curve, even for a very simple system. In this study, a multilinear I load-deformation model that can better approximate the actual material behavior is utilized. The first-moment statistics are derived for the number of load exceedances and damage duration for a structural member due to sustained and combined load processes. It is found that the derived results using a trilinear material model agree very well with the results obtained from simulated data. The differences are usually: within 3% for sustained load processes and somewhat higher, about I 10%, for combined processes.