Capacity Magnification by Imposing Composite Action of Precast Concrete Flanged Girders

This paper presents an experimental study in order to verify the efficiency of different connecting techniques in improving the horizontal shear resistance of composite concrete flanged beams. The studied composite beams consisted of precast concrete webs interconnected with precast concrete flanges. Different connecting techniques had been considered; namely, plain/reinforced Ultra- High-Performance Strain-Hardening Cementitious Composites (UHP-SHCC) shear pockets, UHP-SHCC shear buckets in the flange accommodated extended steel dowels from the web, unbonded internal steel fasteners and intermediate shear intrusions. Eight composite flanged beams incorporating different connecting techniques along with three reference beams; monolithic, successively cast flanged beam and unconnected web/flange beams were prepared and tested up to failure under two cycles of non-reversal repeated loading. Furthermore, the push-off test method was employed in order to determine the horizontal shear resistance of the used connecting techniques. Each technique came up with advantages and disadvantages. Therefore, it is a matter of compromise to decide the most appropriate technique according to the necessary criteria (ultimate capacity or ductility). Finally, the horizontal shear resistances were calculated based on the experimental findings and compared with the stipulated resistances in the ECP 203-2007 and the ACI 318-14 design codes. It was found that the design codes’ values showed conservative results.