A protective structure, saver during structural collapse

In this paper a new protective structure is presented to save human life, in the case of building collapse, caused by an earthquake, a terrorist attack or other catastrophic events. It is well-known that the number of casualties after major earthquakes during night time far exceeds the corresponding number of those events of similar magnitudes occurring that of the day times. The life-saver device discussed here is a bolted-moment-resisting 3-D steel frame that encapsulates a single or double-bed sleeping area at home. The frame consists of a number of beam-columns of angle cross-section, bolted together by gusset plates and topped with a thin steel plate or a rectangular rebar mesh. The collapse of walls and ceilings of the building on top of this structure will result in large plastic deformations in various sections of the frame, whereby the energy of the falling debris is dissipated. Despite these large deflections, no harm is inflicted upon the people sleeping inside the frame. The physical behavior of this new life-saving device, under real situation of structural collapse, is modeled in the ANSYS LS-DYNA software. Combined nonlinear analysis of the frame is performed under dynamic loads developed. It is assumed that the angle members of the frame are stiffened by welding triangular gusset plates at appropriate intervals along their length, so that they behave in a compact manner without local buckling. The discussion of this phenomenon is the subject of another paper and is not presented here. The behavior of the protective structure shows that the people resting or taking refuge inside, will be safe in the event of the collapse of the building. Austenitic twinning induced plasticity (TWIP) steel which has a good combination of both strength and ductility also has been used for modeling and designing this structure and the results has been compared with ordinary steels. The design is verified for the emergency limit state considering the safety of people inside the protective structure. Copyright © 2012 by ASME.