Behavior of Progressive Collapse of Steel Frame under Fire with Different Reduced Beam Section Connections
To explore the influence of different reduced beam section connections on progressive collapse resistance of steel frame structure under fire,first of all,pushdown methods of two-story two-span steel frame beam-column substructure with middle column failure under normal temperature were carried out,and the resistance curves and failure modes in the collapse process were studied.The test results show that the middle column failure steel frame structure mainly relies on the bending mechanism and the catenary mechanism to resist the external load,and the catenary mechanism has hysteresis.Then,on the basis of the test,the two-story plane steel frame model was established by ABAQUS,and the quasi-static simulation at room temperature and fire was carried out.The progressive collapse resistance analysis was carried out on the four beam reduced section connections of RBS(reduced beam section),DRBS(double reduced beam section),OBW(opening beam web)and OBF-2(opening beam flange).The FEM(finite element model)results show that RBS and DRBS can provide higher vertical resistance and deformation capacity than the unreduced model at both room temperature and high temperature.Compared with other reduced beam section connections,DRBS has the best deformation ability considering catenary effect.
steel frame structurereduced beam section connectionspushdown methodsFEM(finite element model)progressive collapse
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