SEISMIC BEHAVIOR EVALUATION OF STEEL MOMENT-RESISTING FRAMES WITH T-STUB CONNECTIONS UNDER EARTHQUAKE RECORDS

Previous conventional steel frame designed to consider the beam-to-column connections in steel frames as rigid or pinned, because design of this type of connection was easy. In general, the connection that welds the beam directly to the flange of the column is considered to be fully rigid. However, the connection that fastens the beam to the column with some angles and/or a plate, bolts or rivets, displays a nonlinear behavior and lies somewhere between the fully rigid and perfectly pinned conditions. Semirigid connections behavior can be shaped and have a good ability to absorb energy. In this paper considered four steel moment frames 3, 6, 9 and 12 floors with rigid and T-stub semi-rigid connection and UBC 97 Regulations for analyzing. A typical T-stub connection cut from a ‘W’ section to the required dimensions was used. Behavior of semi-rigid connections with the M-θ curve in design of steel moment frames used. ETABS software was used for the initial analysis of frames. PERFORM 3D software used for modeling and analyzing of nonlinear dynamical behavior of structures under earthquake records. Nonlinear dynamic analysis results showed in steel rigid frame, more beams and columns have surrendered, while the in steel semi-rigid frame stresses in beams and columns reduced. This is due to the entering of semi-rigid connections the non-linear range. Hence, if we control displacement of the semi-rigid frame, the connection looks well and the frame stable against lateral loading.