LONG-TERM DEFLECTION OF PRESTRESSED CONCRETE BOX GIRDER BRIDGES DUE TO CREEP AND SHRINKAGE

Abstract

Long-term deflection of the box girder prestressed concrete bridge is undoubtedly essential. Creep and shrinkage are significant influences on the long-term deflection. Some design code models do not consider the water-cement ratio as a creep and shrinkage parameter. The excess water-cement ratio will increase creep and shrinkage. B3 Model uses the water-cement ratio parameter to predict creep and shrinkage. This study examines the long-term deflection of the box girder balanced cantilever prestressed concrete bridge that already exists in Indonesia. The method used B3 Model creep and shrinkage prediction to input to the software and used Midas Civil 22 v1.2  software to model the Bridge and the result is compared to other models. The results of this study indicate that the behavior of the B3 Model predicts deflection more significantly than other models. The slope graph of the deflection shows that there is still an increase in deflection after 30 years. It means that moisture loss in the prestressed concrete bridge still occurs after 30 years. From the results, it can conclude that the water-cement ratio is an essential parameter for creep and shrinkage. Prediction of long-term deflection in this B3 Model is extreme but is still within the allowable deflection limit due to dead loads of ACI and CEB codes.