Dynamic Response And Progressive Collapse Of Reinforced Concrete Frame To Explosive And Impact Loads

With the spreading of terrorism,the explosion accident menaced badly the peace and safety of international society in the peace and development times. These explosion accident not only creates the serious destruction in the partial scope to the construction but also brought collapse to entire construction for the structure certain component's destruction. Both in the protective structure and in the industry and civil architecture, it is necessary to consider the effect of blast load. The study of dynamic response of structure under explosive loads is a concerned problem in the engineering field. This article do the research in view of dynamic response of reinforced concrete beam under explosive loads,and has simulated the process of progressive collapse of reinforced concrete frames. Concrete is a porous and brittle material ,there are some disfigurement in the process of pouring concrete and in the initial stage of shaping, such as capillary hole ,interstice , cranny of material and so on, namely initial damage. As a result of the effect of environment factor especially the effect of blast load, the cranny of concrete will worsen rapidly and form new damage. When the damage is accumulated to a certain extent, there will be macroscopical crack in the concrete. In the end the macroscopical crack will expand and interlace and cause the concrete slab to destroy. In addition the concrete is also a sensitive material for rate of strain. When analyzing the response of concrete beam under explosive loads, it is very necessary to consider the effect of damage and rate of strain. A theory analysis and numerical simulation on dynamic responses for concrete slab considering effect of damage and rate of strain under blast loads is performed in this dissertation and has compared the situation of progressive collapse to different structure's element be destroyed. Through the above research analysis, obtains the following result:1. Obtains by the theoretical calculation,along with reduced scale distance,deflection of beam reduces unceasingly,the deflection of beam is small than that did not consider rate of strain. The rate of strain is larger the deflection of beam is smaller. The deflection of beam is larger than that did not consider material with damage,deflection of beam is small than that Both the consideration rate of strain effect material with damage,thus we know the design tends conservative when not to consideration.2. Uses simplified exponential form for detonation load has been analysis displacement of Y direction and stress and Z direction away from numerical simulation. And has carried on the numerical simulation result with the third chapter of theoretical calculation result the contrast,obtained the magnitude of error.3. The frame structure become the suspended cable after first floor column of frame construction suffers the destruction,thus creates collapse. The construction collapse destruction begins in other corner cloumn crushing,as well as beam pulling badly after the first floor corner column be destroy.