On the seismic performance of a New low damage Structure; Moment Resisting Frame with Post-Tensioned Connections and Frictional Braces

Regular structural systems have been designed based on supplying sufficient ductility in seismic events, which lead to considerable permanent deformation after major earthquakes. Buildings with Large permanent deformation usually are unusable or require extensive repairing. Therefore, low damage structural systems are recently focused. The present study aimed at introducing a new self-centering structural system having frictional sliding in their braces. It is compared with common dual steel moment frames. In the proposed system, post-tensioned cable is used in beam to column connections to provide self-centering. The frictional sliding connections in the braces are utilized as well, to provide energy dissipation capability for the system. Connections are modeled in OpenSees software and validated using previous experimental results. Then, Incremental dynamic analyses are carried out on some frame models under some real earthquake records. Then, their fragility curves are achieved for different performance levels and compared with those of regular dual systems. The results indicate that supplying post-tensioned cables and frictional sliding connections in dual moment frames, reduces the inter story drift, permanent relative displacement and vulnerability of the frames. Therefore, construction of such system for new buildings is recommended, regarding its high performance in earthquakes and repairability after intensive seismic events.