Creep influence on structural dynamic reliability

Abstract

Creep brings forth considerable influences on both static and dynamic behaviours of concrete structures. This paper intends to deepen the investigation on the creep influence on structural dynamic performance, evaluating their relationship from the view of reliability. The influencing mechanism of concrete creep on structural dynamic behaviour is first stated. Integration of the structural creep analysis by the Model B3 and the age-adjusted effective modulus method with the stochastic seismic analysis by the pseudo-excitation method is then proposed. Based on the creep-influenced structural static and stochastic seismic behaviours, formulations for the dynamic reliability with the consideration of creep effect are derived using the first-passage failure criterion and Poisson crossing assumption. A systematic numerical simulation is conducted on a long-span concrete filled steel tube arch bridge, considering (1) the creep influence on concrete mechanical properties and structural configuration and internal forces; (2) the dimensionality, wave passage effect and incoherence effect of random ground motions; and (3) the uncertainties existing in the structure and creep behaviour. Critical conclusions are drawn and it is recommended to consider the long-term effect of dead loads in seismic design to ensure structural seismic safety.