Experimental evaluation of in-plane seismic demand on power actuated fasteners (PAF) connecting CFS drywall partitions and concrete surrounding elements

The evaluation of the response of cold-formed steel (CFS) drywall partitions under in-plane earthquake loading is one of the open tasks for understanding the impact of nonstructural elements on the seismic performance of constructions, especially when the implementation of performance-based earthquake criteria is required. In this context, the evaluation of the seismic demand on fasteners connecting drywall partitions with the surrounding structures has not been well covered. To overcome this gap, a specific experimental study devoted to evaluate the in-plane seismic demand on power actuated fasteners (PAF) connecting CFS drywall partitions and concrete surrounding elements is presented in this paper. In particular, the experimental activity includes seven quasi-static reversed cyclic tests on full-scale drywall partitions. Parameters under investigation are: type of surrounding connections; type of sliding connection; spacing of PAFs. From global point of view, results showed that the main parameter affecting the seismic response of the drywall partitions was the type of surrounding connections. PAFs connecting both studs and tracks to concrete surrounding elements exhibited elastic behaviour without significant damage in all tested walls with seismic demand equal to 0.50 mm in terms of displacement, 1.9 kN in terms of force per single PAF, 4 kN/m in terms of force per unit length of the wall. Therefore, with reference to the design process, for typical single stud drywall partitions having common high of about 2.6 m sheathed on both faces with two layers of 12.5 mm thick standard gypsum wall boards fixed to the steel frame with self-piercing screws (spacing of 1000 and 250 mm on the centre for the interior and exterior panels, respectively), in which connections between wall and surrounding elements are made of Hilti X-X PAFs spaced in the range from 300 to 500 mm, the PAFs exhibited an elastic behaviour resulting over-strength elements in all studied conditions.