Experimental study of concrete hinge connections with usual details

Applying hinge connection in concrete building can sometimes decrease element sizes and improve seismic behavior of the structure. Despite of many details for such connections in special structures such as bridges, there is not any detail, accepted by both scientists and engineers, for hinges in regular concrete buildings. The existing details, in which the longitudinal reinforced bars cross each other at the center of the section, have not been verified well by experimental tests, therefore, they are not applied in practical projects. In this study two details, proposed for hinge connections are experimentally studied. In this regard, three cantilever concrete beam specimens with different connections were constructed and loaded by displacement-controlled loading. The first specimen had rigid connection that was used as a reference to be compared with other specimens. Both the second and third specimens had crossed reinforcements at the hinge part; however, the last one was also equipped with two grooves at the top and bottom of the section.
Moment- rotation diagrams of the specimens were compared to find their connection rigidity. The results show that connections with crossed reinforcement with or without grooves cannot be considered for hinge connections, for their brittle behaviors and considerable bending strengths.