Dynamic Behavior And Catenary Action Analysis Of Horizontally Restrained Steel Beam Under Impact Loading

Frequent building fires, earthquakes, explosions and terrorist attacks have causeddisastrous casualties and property losses because of building collapse, so moreattention has been focused on how to design reasonable structures to withstandprogressive collapse. As the key elements in steel frame structures, the behaviors ofbeams have significant effects on the progressive collapse-resisting capacities ofstructures under terrorist attacks and other impact loading conditions. The dynamicresponse together with the development mechanism of catenary action of the mid-spansection of the axially-restrained steel beams was experimentally investigated using adrop hammer test machine in Hunan University. Also the nonlinear FE simulation wasdeveloped using the ABAQUS program. The research work can be summarized asfollows:(1) An impact test setup which can axially restrain the steel beams wasdeveloped to experimentally study the dynamic behaviors and inner forcedevelopment of the tested specimens under impact loading applied by the drop hammer.(2) Drop weight impact tests on the restrained steel beams were carried out andthe tested parameters including shaping process of beam, the ratio of width tothickness, impact height and impact energy were considered to study the influence of thetested parameters on the impact force, deformation and inner force development.(3) The finite element model of axially-restrained steel beams under impactloading was developed using ABAQUS/Explicit, and the dynamic behaviors, innerforce development and catenary action were analyzed. The numerical results were ingood agreement with the experimental results.(4) The mechanism of catenary action of mid-span axially-restrained steel beams,which were widely used in real projects, were analyzed under inertia force caused bygravity distribution due to loss of column. Besides, the effects of the strength ofmaterial, span to depth ratio, section dimension and end constraint condition of steelbeams on the forming and development process of catenary action were investigated.The results would provide valuable reference to evaluate the ductility of the structureto resist progressive collapse as well as anti-progressive collapse design approach.