Improving seismic design efficiency of petrochemical facilities

This research studied the seismic performance of equipment support structures with knee-braced moment-resisting frames in petrochemical facility construction. Frame performances were evaluated using the structural stiffness, strength, and ductility. It was found that frame stiffness increases when the magnitude (e_b) and slope of knee braces (e_c/e_b) increases. For practical purposes, it is suggested that the e _c/e_b ratio be kept at 1 and e_b less than 0.25 times the beam length. It was also observed that the maximum member forces in traditional special moment-resisting frames are shifted from the critical beam-column joints to the beam-knee brace intersections, which greatly reduces the risk of brittle fracture at those regions and significantly enhances the structural ductility.