Innovative testing procedures for a high-performance, pre-formed mechanical connection system between concrete slabs and walls

![CDATA[Slip-formed construction of major concrete cores can be enhanced by the provision of preformed mechanical connections that allow the main slab reinforcing bars to be mechanically connected to cast-in inserts and achieve their full tensile capacity. The results of two innovative full-scale tests on slab-to-wall insitu connections incorporating a high-performance, pre-formed mechanical connection system are presented. The test set-up comprised a propped cantilever, the end of which could be lowered into a range of positions allowing the bending moment acting on the connection to be varied independently of shear force. This way, slabs of any flexibility could be modelled. In one specimen, the coupled bars were at the mid-depth of the slab, while in the other they were in two layers making the connection rotationally stiffer and flexurally stronger. The bending moment, shear force and rotation a the connection were determined for all stages of loading. Even under large rotations, possibly while a plastic hinge had formed, the maximum applied shear force reached over five times the design ultimate shear force in both tests. Premature shear failure of the slabs, and pull-out failure of the bars in the walls were avoided by appropriate detailing. In particular, the use of hooked top bars and cogged bottom bars in the ends of the slabs adjacent to the connection is strongly recommended. Data from the tests is being used to develop new AS 3600 design provisions for mechanical splices.]]