ASSESSMENT OF PROGRESSIVE COLLAPSE CAPACITY OF DUAL STEEL CONCENTRICALLY BRACED FRAMES WITH SEMI-RIGID CONNECTION

Abstract

This research investigates progressive collapse phenomena of steel braced frames (dual system) with semi-rigid connections assigned at beam-column joints, due to abnormal loading events. This phenomena occurs when one or more of major structural members cannot resist over loads due to sudden removal of structural elements. Two dimensional (2-D) analytical models are created using a commercial computer program SAP2000 and designed according to American Society of civil engineers (ASCE, 7-05). And followed by progressive collapse procedures due to General Service Administration (GSA, 2003). Linear static analysis and linear time history analysis were carried out for progressive collapse evaluation using semi-rigid connection definition at beam to column joints. A variety of structural models are analyzed for progressive collapse conditions using variable definition of structural models. These parameters are defined variously for number of stories, story height, span length and number of bays with different locations of removed members. The results are investigated according to structural members demand capacity ratio (DCR), vertical displacement upon point of column removal and lateral story drift. Effectiveness of semi-rigid connection was investigated and compared with results using fully-rigid connections.