Failure Mechanism of Composite Frames Under the Corner Column-Removal Scenario
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TECHNICAL ARTICLE—PEER-REVIEWED
Failure Mechanism of Composite Frames Under the Corner Column-Removal Scenario Haohao Zhang . GanPing Shu . Rui Pan
Submitted: 12 June 2018 ASM International 2019
Abstract The beams and the slabs of a composite structure act jointly as an integrated floor system to resist progressive collapse. Ignoring the composite slab’s contribution to strength and ductility will result in significant underestimation of the vertical force resistance. In order to investigate the effect of composite slabs on the failure mechanism and the distribution of the resistance, a series of simulation and theoretical studies have been conducted on the progressive collapse of beam–slab substructures by removing corner column. This article discusses the contribution of several mechanisms on the load-carrying capacity. It is found that the composite slab can significantly improve the progressive collapse resistance of the composite structure. Under catenary mechanism, the peak load of the beam–slab specimen is approximately 1.15 times the beam specimen. In addition, the maximum angle in the beam end of the beam–slab specimens reaches 1.33 times that of the beam specimen. The progressive collapse process of the structure can be sectioned into four stages which are the elastic stage, the elastoplastic stage, the plastic stage and the collapse limit stage. Before the elastoplastic stage, the collapse resistance is contributed by the flexural strength of the composite frame. Sometimes the
H. Zhang (&) Municipal Construction Engineering Affairs Center, Fuyong Sub-district Office of Bao’an District, Shenzhen 518103, China e-mail: [email protected] G. Shu R. Pan Key Laboratory of C & PC Structures, Ministry of Education, Southeast University, Nanjing 210096, China G. Shu R. Pan School of Civil Engineering, Southeast University, Nanjing 211189, China
longitudinal shear bearing capacity of the composite slab will significantly affect the flexural strengths. After the elastoplastic stage, the collapse resistance is mainly determined by the catenary mechanism of the beams and tensile membrane action of the steel sheet. Keywords Progressive collapse Composite frames Closed profiled steel sheet Tension membrane action Catenary mechanism Introduction Profiled steel sheet–concrete composite slabs can make full use of the mechanical properties of both steel and concrete. It has been extensively applied to engineering. The result shows that most composite slabs failed in longitudinal bonding failure modes, which is different from the cast-inplace floor. Extensive studies show that the progressive collapse resistance of structures is greatly enhanced by the catenary mechanism in reinforced concrete (RC) frame structures while undergoing large deformations [1–4]. However, whether there are catenary mechanisms, arching effect or membrane effect in the composite structure remains an open question. Recently, more experimental tests are presented on building structures under such extreme loading conditions. However
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