Response And Reliability Of Reinforced Concrete Beam Subjected To The Explosions

It has been studied and discussed that the dynamic response and reliability of the reinforced concrete beam and slab are subjected to the explosive blasting load adopting the theoretical analysis and mathematical simulation method. The main work contents of this paper are as follows:(1) The approximate calculating method adopted in the reinforced concrete structural design to the protective structure is discussed. The reinforced concrete beam is considered as the single particle system, based on the ideal elastic-plastic theory, and motion equation is solved, then the elastic-plastic dynamic curve of the internal force and deformation of single freedom system is obtained; Finally based on the single particle spring-mass system, one simpler spring-mass analogy method is give, which provides the reference for the protective project design.(2) A new load generation method and simulation method of steel bar are proposed adopting the large FEM program LSDYNA. Three examples of reinforced concrete beam including flexural failure, brittle failure and direct shear failure under blast load are presented considering the effect of reinforcement. Part numerical results match reasonably well with experimental data.(3) Two loosely coupled SDOF systems are used to model the flexural and direct shear responses of simply supported reinforced concrete beams designed based on the actual code subjected to explosive loading. Incorporating the effects of random variations of the material strength, structure dimensions and blast loading properties, as well as the strain rate effect, failure probabilities of the two failure modes are analyzed adopting the FOSM method and the small sample number fitting method utilizing the valuable experimental formulation in the related literature. The reliability of the simply supported beam is analyzed subjected to the explosive loading with different amplitude and duration time.(4) Besides the influence of beam span lengths are investigated. A semi-analytical boundary has been derived to predict the failure mode of a slab in terms of its span length L, surface area A, and the peak reflected pressure and pressure loading duration based on the numerical simulation results.