OPTIMUM DESIGN OF LONG-TERM DEFLECTION IN SEGMENTED PRESTRESS BRIDGES BY CONSIDERING THE EFFECTS OF CREEP AND SHRINKAGE

The purpose of this study is to evaluate the long-term vertical deformations of segmented pre-tensioned concrete bridges by a new approach. It provides a practical and reliable method for calculating the amount of long-term deformation based on creep and shrinkage in segmented prestress bridges. There are various relationships for estimating the creep and shrinkage of concrete. The analytical results of existing models can be very different, and the results are not reliable. In this paper, the different existing relationships are written in MATLAB software. After calculation, the values of the creep and shrinkage are stored. Then a sample bridge is simulated in the CSI-Bridge software, and different values of creep and shrinkage are allocated separately. Therefore, the data are analyzed, and its maximum deformation value is extracted at a critical span (Dv-max). Assigning different amount of creep and shrinkage to the model results in different values  of Dv-max. In the next step, all Dv-max values  resulting from the change in creep and shrinkage contents should be re-introduced to MATLAB code to perform the calculation of the failure curve, and extract the corresponding Dv-max values at ۹۵% probability. In a new approach, fragility curves are used to obtain the corresponding creep and shrinkage values corresponding to the desired probability percentage. Thus, instead of simulating several models, only one model is simulated. The results of the analysis of a bridge sample in this study indicate acceptable accuracy of the proposed solution for the ۹۵% probability.

Keywords:

Segmented Prestress Bridges , Creep , Shrinkage , Long-Term Deformation , Concrete.