... Tall Buildings" (JGJ99-9) Commonly used steel grades and performance of steel:· Carbon structural steel: Q195, Q215, Q235, Q255, Q275 ... low-alloy structural steel· Quality carbon structural steel and alloy structural steel· Special purpose steelSpecifications:Main Steel: Column and beam ... do)Crane: 5T,10T,15T,ect.Bolt: Foundation bolt(M24,Q235), High strengthen bolt(M20X70) , Normal bolts(M16x50;M12X30 ...