Seismic testing and retrofit of steel deck roof diaphragms for building structures

An experimental program of nine steel deck roof diaphragm specimens was carried out to assess their seismic characteristics. The dynamically loaded diaphragms were able to develop the shear strength but not the shear stiffness values calculated using current diaphragm design methods. Furthermore, the shear stiffness decreased with increasing excitation amplitude. Diaphragm ductility decreased with the use of thicker deck panels and when the deck was oriented parallel to the loading direction. Most of the damaged diaphragms could be repaired to recuperate their original strength. A seismic retrofit scheme was effective in increasing the shear strength and stiffness of an arc-spot weld/ button-punch diaphragm.

► Dynamic tests of nine diaphragm specimens with various connection patterns.
► SDI method overestimates shear stiffness at high amplitude excitations.
► Measured shear strength in agreement with SDI predicted value.
► Weld/button-punch and thicker nail/screw diaphragms exhibit lower energy dissipation.
► Retrofit of the arc-spot weld/button-punch diaphragm proved effective.