The prediction of long-term deflection of large-span prestressed concrete bridges is a serious challenge to the current progress towards sustainable transportation system, which requires for a longer service lifetime. Although a number of concrete models and numerical formulations were proposed, the accuracy of prediction is not satisfactory and significant underestimate happens in structural analysis.udIn order to overcome this obstacle, a unified viscoelasto-plastic damage model is proposed for the prediction of long-term performance of large-span prestressed concrete bridges carrying heavy traffic flow. In this unified concrete model, concrete cracking, plasticity and history-dependent behaviors (e.g. static creep, cyclic creep and shrinkage) are coupled. The isotropic damage model developed by Tao and Phillips enriched with the plastic yield surface is used in this study. For the static creep and shrinkage models, the rate-type formulation is applied so as to 1) save the computational cost and 2) make it admissible to couple memory-dependent and -independent processes. Cyclic creep, which is frequently ignored in structural analysis, is found to contribute substantially to the deflections of bridges with heavy traffic loads. The model is embedded in the general FEM program ABAQUS and a case study is carried out on the Humen Bridge Auxiliary Bridge. The simulation results are compared to the inspection reports, and the effectiveness of the proposed model is supported by the good agreement between the simulation and in-situ measurements.
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