Shear-critical reinforced concrete beams under sustained loading
Part I: Experiments

R. Sarkhosh, J.C. Walraven, J.A. den Uijl

Delft University of Technology, Faculty of Civil Engineering and Geosciences, Group of Concrete Structures, the Netherlands

Several experiments were carried out on reinforced concrete beams without shear reinforcement subjected to high sustained shear loads close to the short-term failure load. The goal was to investigate the behaviour of shear-critical concrete beams under sustained loading. The beams were subjected to the load for a minimum period of three months. Meanwhile, the deflection, crack growth and crack widths were measured. A total number of 42 reinforced concrete beams have been tested. Amongst them, 24 beams were tested under monotonically increased short-term loading, in order to obtain reference values for the shear resistance, the crack width and the type of failure, and to gain insight into the scatter of the results. The 18 other beams were subjected to long-term sustained loading with high load levels: the ratio of applied shear load to short-term shear resistance was between 0.87 and 0.975. Furthermore, at the end of the period of long-term loading, the concrete beams were tested to failure. The program was carried out in order to determine advanced rules for the shear bearing capacity of existing bridges in The Netherlands. For the full background information reference is made to Sarkhosh (2014)