Dynamic investigation of concrete bridges taking into account time-dependent effects

Abstract

This paper presents a systematic approach to study the effects of long-term time-dependent behaviour due to ageing of concrete, concrete creep, concrete shrinkage and cable relaxation on the dynamic properties of concrete bridges. An equivalent stress relaxation model is introduced to obtain the equivalent creep coefficients of prestressing tendons. Based on this, the time integration method for prestressing tendons is developed. A bridge is modelled properly by finite element method using the master-slave technique to ensure compatibility between the concrete member and tendons. Time-dependent analysis is then conducted using time integration considering the interaction among various time-varying factors. Finally, on the basis of the updated finite element model, dynamic properties of the concrete structure are investigated by the subspace iteration method. The effects of long-term time-dependent behaviour on the dynamic properties of typical concrete bridges are then examined in detail. © 2011 Taylor & Francis Group, London.