Portal steelstructure is a ligh steel structure system with portal frames as the main load bearing structure, commonly used in large-space buildings suchas single-story workshops, warehouses and exhibition halls.It consists of steel columns, steel beams, purlins and enclosure panels, with high prefabrica-tion degree and fast on-site instalation. It features light weight, large span, economical cost and good seismic performance, making it the most widely

used structural form in industrial and storage buildings at present.