Experimental study of typical and retrofitted jack arch slabs in a single story 3D steel building

Seismic retrofit of masonry slabs in existing steel or masonry buildings has found special significance in current codes asfailure of unstable jack arch slabs has been reported as a major reason for collapsing structures in middle east deadlyearthquakes. in this paper, three retrofit schemes are investigated and compared. the proposed rehabilitation techniquesconsist of a single x strapping, sxs, a double x strapping, dxs, and a two-way jack arch slab supported by a steel grid. usingexperimental studies, advantages and disadvantages of each scheme are evaluated. in-plane stiffness and capacity of thediaphragm are adopted as the seismic performance index of each rehabilitation scheme.according to the obtained results, the jack arch slab systems designed and constructed based on proposed retrofit methodsprovide an appropriate alternative to other forms of flooring in seismic zones. dxs can greatly improve diaphragmperformance in terms of in-plane stiffness, capacity and even energy dissipation of the diaphragm compared with the other twotechniques. the second place belongs to sxs while the steel grid scheme has a minor effect on the in-plane stiffness of thediaphragm.