seismic behavior of post-tensioned steel connections with top and seat angles

post-tensioned (pt) connections are used in steel moment resisting frames to eliminate structural damage and minimize residual drifts under seismic loads. a steel post-tensioned connection with top and seat angles has recently been developed. the connection includes top and seat angles bolted to the beam and column. strands are placed along the length of the beam, passing through the column and posttensioned to provide a pre-compression of the beam against the column. the angles act as energy dissipation devices in pt connections. in this research the seismic responses of steel buildings with semi rigid posttensioned connections (pt) are estimated and compared with those steel buildings with typical rigid (welded) connections. different parameters influence on behavior of pt steel connection. the parameters investigated in this study include the angle size, angle gage length, beam flange reinforcing plates, shim plates, number of strands, initial posttensioning force and stiffened angles. the obtained results show that mrf wit pt steel connections represent better behavior in respect with mrf with welded connections. also it can see that by increasing number of strands, angle size, initial posttensioning force and adding stiffener to angles, pt connection represent better behavior, and increasing gauge length decreases moment resistant of the frame.