Nonlinear seismic performance of integral prestressed concrete boxgirder bridge in Malaysia

Abstract

Currently integral and continuous concrete box-girder bridges are becoming popular system in Malaysia. The problem occurs in such system is the rigidity connection of column and deck will lead to potential hinge failure. In this research, nonlinear seismic performance for this type of bridge was studied by applying soil – pile interaction and fixed base support system. The study covers numerical and experimental approach. The numerical approach has four steps as follows: (1) investigating material properties of integral prestressed concrete box-girder bridge; (2) modelling integral prestressed concrete boxgirder bridge by considering the interaction of structure, substructure and site condition; (3) studying the soil and pile interaction by applying bridge finite element modelling. (4) Validating experimental modelling with Finite element Modelling. As for the result validation, the four steps in the experimental approach involved: (1) scaling the integral concrete box-girder bridge by implementing Buckingham PI theorem; (2) setting the shaking table, shaker controller, LVDT, strain gauge and accelerometer; (3) analyzing finite element modelling of the scaled integral concrete box-girder bridge and (4) Validating the results by comparing the acceleration, displacement of structure response from instrument and finite element modelling. In this study, it was found that the behaviour and response of integral prestressed boxgirder bridge under seismic loading do not reach the yield level for low intensity earthquake. However, for moderate and high seismic intensity, the bridge response reached the yield level but still was under immediate occupancy level. Furthermore, the effect of soil-pile interaction for integral prestressed concrete box-girder bridge showed that the total displacement at the top of pier is 80% higher than fixed base support under longitudinal earthquake direction, while 87% higher under transversal direction. By conducting experimental shaking table test for integral concrete boxgirder bridge model, the seismic bridge response from finite element modelling (numerical approach) presented the approximate behaviour of integral concrete boxgirder bridge under earthquake loading. The findings in this research suggest that seismic loading effects should be considered in the design of integral prestressed concrete box-girder bridge due to higher displacement value compared to the one of the thermal loading.