Effects of Surface Roughness on the Behavior of Interface between Old and New Deck Slabs Under Concentrated Load

Abstract

Experimental and analytical studies on the behavior of interface between old and new deck slabs were investigated in this study. The test was performed to represent a bridge widening method that has been developed in Japan. Therefore, each specimen consist of the old and new deck slabs. The connection between those deck slabs was varied into a rough and smooth surface. Before testing, the slabs were prestressed using unbonded PC rods which amount of 1.0 MPa. The result of this study indicated that the difference in the level of roughness does not provide a significant effect on the ultimate capacity. Remarkable effects were only observed on crack pattern, deflection, and joint opening behavior. To validate the experiments, the ultimate capacity of experiment was compared with the predicted shear capacity obtained from JSCE Specification and fib Model Code. In the guidelines, the area of the interface is assumed as the total area of the interface. However, such assumption cannot be used in this study. Therefore, the effective area of the interface obtained from FEM analysis was proposed in this study. Eventually, by using the proposed effective area of the interface, the calculated results showed that all guidelines provide a good lower limit to predict the ultimate capacity of the deck slabs.