Simulation Of Blast Loading On Buildings In Urban Environment And Analysis On Blast-resistant Behavior Of RC Members

The damage of buildings due to terrorism or the accidental explosion induced huge economic and life losses in recent years. In order to learn more about the failure mechanism of building structures under blast disaster, the spread of blast waves in urban complex environment and blast loading on buildings are simulated. And the dynamic responses of reinforcement concrete (RC) members under blast loadings are studied. And the primary work and achievements are as follows. 1. The numerical model of explosion on the rigid ground outside the building is established using the explicit finite element analysis software AUTODYN. The process of explosion shock waves spreading in the free air and reacting with the building is simulated. The distribution of blast overpressure on the front, side and back surface of the building are studied. The influence caused by openings of doors and windows on the blast overpressure on the structure is analyzed. 2. The numerical models of blast shock waves spreading in complex urban environment are established. The reflection and block effects for bla??hock waves by adjacent buildings are analyzed. And the spreading law of blast waves in the T-shape??reet is studied. The features of external blast loading on buildings in a variety of circumstances are described, considering the influences of the height and position of adjacent buildings and the width of street on the spreading of blast shock waves. 3. Based on non-linear finite element method, numerical analysis models of RC members, such as beams, columns and slabs are established using transient dynamic analysis software LS-DYNA. The dynamic response of structure members subjected to blast loading is calculated to study the law of their displacement and internal forces caused by the impact of the blast loading. The time histories of stress and strain of reinforcement and concrete material are given and compared with the results of the experiment. The numerical analysis models of RC members are proved to be valid and correct. 4. The dynamic response of RC members under different blast loadings are simulated on the base of the numerical analysis model. The possible failure modes of RC members are analyzed according to the distribution of their stress and strain. So the change law of failure modes of RC members under different blast loadings is given. 5. Through the parametric analysis of RC members subjected to blast loading, the dynamic responses of RC members with different concrete strength, cross section and reinforcement ratio under same blast loading are calculated. The influence of geometric and material parameters on the blast-resistant behavior of members is analyzed. And the main factors that influence the blast-resistant behavior of RC members are given. So some theories and suggestions are presented to determine reasonable parameters in the design of blast-resistant buildings.