Abstract: (7361 Views)
Seismic retrofit of masonry slabs in existing steel or masonry buildings has found special significance in current codes as
failure of unstable jack arch slabs has been reported as a major reason for collapsing structures in Middle East deadly
earthquakes. In this paper, three retrofit schemes are investigated and compared. The proposed rehabilitation techniques
consist of a single X strapping, SXS, a double X strapping, DXS, and a two-way jack arch slab supported by a steel grid. Using
experimental studies, advantages and disadvantages of each scheme are evaluated. In-plane stiffness and capacity of the
diaphragm 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 methods
provide an appropriate alternative to other forms of flooring in seismic zones. DXS can greatly improve diaphragm
performance in terms of in-plane stiffness, capacity and even energy dissipation of the diaphragm compared with the other two
techniques. The second place belongs to SXS while the steel grid scheme has a minor effect on the in-plane stiffness of the
diaphragm.