Studies On The Effect Of The Deformation Of Panel Zones On The Steel Rigid Frames Response

Steel moment frames are widely used for seismic design in the United States and Japan , and highly regarded structural systems , but severe damage to steel frames occurred during the 1994 Northridge and 1995 Hyogoken-Nanbu earthquakes . A brief history of the engineering in the United States and Japan is provided , and current design methods are summarized and compared.In steel frames structural stability and resistance to lateral loads require the transfer of bending moments between beams and columns . Depending upon stiffness and strength requirements , this transfer of bending moments can be achieved by either semi-rigid or rigid beam-column connections . In both case , the intersection between beams and columns (the beam-column joint)will be subjected to high shears .Panel zones usually are very ductile elements capable of undergoing severe inelastic strain reversal without a decrease in strength . Maximum strength and stiffness of frames is attained when all joints are design for the maximum shear force that can be developed based on the strength capacity of the members framing into joint. So the panel zones should be permitted to participate in energy dissipation trough inelastic deformation . However , the design strength is reduced considerably though the use of a resistance factor of 0.7 , 0.8 , and 0.6 if the intent is to allow such panel zone distortions to occur all.The use of Equation provided by codes implies that some inelastic panel zone distortion is expected at the predicted strength , and therefore the panel zone is expected to contribute to energy dissipation in a controlled manner during severe seismic loading .The finite element models utilized in this study , and analysis and results are hoped to be some proof for the code modification .