Behavior Of Steel Moment Resisting Frame With Reduced Beam Section

Abstract

Extensive research became a necessity after the fall back of Moment-Resisting Frames during 1994 Northridge earthquake and 1995 Kobe earthquake. Reduced Beam Connections used in Moment Resisting Frames emerged as one of the most economical connections for the better ductility enhancement. The performance of Reduced Beam Sections under cyclic loading has been found advantageous by under- taking several experiments. The global parameters are also affected by incorporating Reduced Beam Sections in to the structure. Guidelines for Design of Reduced Beam Section have been suggested in several codes and documents namely, FEMA 350, EC 8 and AISC 358. Here, Design of Reduced Beam Section suggested by several guidelines, has been studied. EC8 and AISC 358 have derived the guidelines from FEMA 350 itself. For a particular steel section, the design has been done and compared. A G+15 storey steel building with and without RBS are modelled in STAAD.Pro V8i. The verification of results from STAAD.Pro V8i has also been done considering a portal frame. The effect on Time Period, Base Shear, Displacement and Storey Drift has been compared. The Time Period of the G+15 storey building has increased by the incorporation of RBS due to the reduction in the cross-section of the beam members. The Base Shear shows no much change as the reduction in weight because of use of RBS is very less. The increase in the Displacement and Storey Drift has been observed at each storey. The FEM analysis of Beam-Column Assemblies with and without RBS has been done using ANSYS Workbench 14.5 to see the variation in de ection of beam and in the stresses at several critical locations. The parameters - Total deformation and Equivalent Von-Mises Stresses - are compared. The de ection of cantilever beam increases with the use of RBS but the benefit is observed in terms of reduction of stresses at several critical locations such as Beam End and Panel Zone.