Progressive Collapse Behaviour And Design Method Of Multi-story Steel Frames

With the rapid growth of Chinese economy, a large number of steelstructures with different structural configurations are being constructed everyyear including multi-story steel frame structures. The theory of steel structuresdesign and constructing technology have been improving while the research onthe progressive collapse of steel structures in service is not enough to meetengineering demand and the development of the related theory and research isstill in primary stage which falls behind some other countries. What’s more,some structural details of domestic steel structures are not the same as the onesin other contries in terms of joint types and configurations, etc. This papermainly studies the progressive collapse performance of multi-story steel framestructures, which mainly includes:(1)Based on a progressive collapse experiment of two-story steel-composite frame, a finite element model was established using the softwareANSYS. The technology of finite element modeling and analyzing byANSYS/LS-DYNA was introduced in detail such as parameter settings, failurecriteria, etc. In the end, the method was validated by the test results.(2)Based on an office building, a finite element model representing amulti-storey steel frame with floor slabs was established. In order to simulatethe progressive collapse loading scenario, the method called transient loadingunder ANSYS/LS-DYNA software environment was conducted, and to evaluatethe post-damaged structure’s anti-collapse capability. This paper mainlysimulated the response of the whole structure under one column lost scenarioand multiple columns lost scenarios.(3)Based on the different parameters of an office building, a serial of steelframes with floors were designed by MIDAS. The bearing capacity of these steelframes was nearly the lower bound of code for steel structure design consideringthe seismic design. The parameters include the longitudinal span, the transversespan, the longitudinal span number, the transverse span number, the story height and story number, the intensity of earthquake, etc. The progressive collapseperformances of these frames were studied by ANSYS/LS-DYNA.(4)Based on the existing progressive collapse design codes of differentcountries, and some research results, general design principles and someparticular design suggestions were introduced in this paper according to thepractical situation of multi-story steel frames design in our country.