Creep of Concrete under Stochastic Live Load.

摘要

The probabilistic deflection of concrete beams is modeled,taking into account the creep behavior of the concrete and the variability of gravity loads as modeled in recent live load studies (both in magnitude and in time). The creep parameters of the concrete are modeled as random variables,as are the magnitude and time between changes of live load,and the cross-sectional properties of the beam. Parameters describing concrete behavior are considered nonchanging with time (which is a valid assumption during most of a structure's life);extension of the model to include initial effects would not be difficult. The mean and variance of the beam deflection are calculated,as well as fractiles of the maximum lifetime deflection,taking into account discrete deflection changes due to changes in live load and continuous deflection changes due to the creep behavior of the concrete. Results are presented as a function of the mean rate of change of the stochastic live load.