ISSN: 1304-7191 | E-ISSN: 1304-7205
Seismic performance evaluation of eccentrically braced steel frame buildings
1Department of Civil Engineering, IIT Delhi, New Delhi-110016, India
2University Polytechnic, Aligarh Muslim University, Aligarh-202002, India
Sigma J Eng Nat Sci - DOI: 10.14744/sigma.2023.00075
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Eccentrically braced framing (EBF) systems have been in use for the past few decades, however, there seems to be little consensus on the amount of ductility capacity available in the EBF system, among code committees of different countries. This is reflected in the variation in the response reduction factors specified for EBF systems in different national design codes. Indian design code specifies a response reduction factor of 5 for EBF systems. Whether this much reduction in the design earthquake forces gives intended performance for the buildings with EBF system, needs to be verified. In the present study, an attempt has been made to verify the adequacy of the response reduction factor given in the Indian code for EBF buildings using the procedure given in FEMA P695. Adequacy is checked for 5 storey archetypes of EBF system having built-up sections and Indian Standard rolled steel sections as link members. The building models have been subjected to Incremental Dynamic Analysis (IDA) using a suite of 22 ground motions given in FEMA P695 to obtain the collapse margin ratio. The obtained collapse margin ratio has been adjusted for spectral shape correction and then checked against the acceptable value of collapse margin ratio given in FEMA P695 to verify the adequacy of the Response reduction factor used in the design.