Punching shear in flat slabs with open stirrups as shear reinforcement

The performance of open stirrups shear reinforcement not fully anchored is investigated, with a type of detail that has been used in construction sites as a support for the top flexural reinforcement to guarantee the right height position; and subsequently, it has also been used to address punching. Five internal slab-column connections subjected to symmetrical loading were tested, including a reference connection and four connections with anchorage variation of shear reinforcement, and their performance was compared with estimations by Codes and Standards and with test results from other authors. Even though the tests presented showed that an increase from 25% to 45% in the punching resistance can be achieved, and that the deformation capacity can also be improved, more tests with other detailing, ratios of flexural and shear reinforcement, and so on, are needed before it can be recommended as an effective shear reinforcement alternative.