TIME-DEPENDENT STRUCTURAL SERVICEABILITY ANALYSIS OF CONCRETE STRUCTURES

The ACl model for creep effect and Gaussian stochastic processes (stat ionary or nonstationary) for applied loads are adapted in developing a n analytical solution for time-dependent structural serviceability pro blems when the deformation of concrete structures under the effect of concrete creep is of interest. It has been noted that this problem cou ld be best approached using upcrossing rate concept in stochastic proc ess theory because both the applied loads and creep effect are not onl y random but also time-variant. This is attractive theoretically, but definitive procedures have not yet been fully developed when time-depe ndent variations of the structure or its properties are involved. In a ddition, the structural response under the actions of concrete creepin g and stochastic loading is a nonstationary process even when the appl ied loads are stationary since the creep effect is nonlinear in time. An example is given to illustrate the proposed approach and a comparis on is made with simulation results.