Study On Dynamic Response Of Fabricated Reinforced Concrete Superimposed Beams Subjected To Explosion

In recent years,with the development of the construction industry and the support of policies,fabricated buildings are gradually popularized in urban construction.As an important component of fabricated buildings,superimposed beams have always been a research hotspot.At present,there are few research results on the blast performance of superimposed beams,and they are mainly concentrated on numerical simulation.There are very few research results on field explosion experiments,making it difficult to evaluate the safety performance of structures under accidental explosion loads,which to some extent limits the application of prefabricated concrete structures.Therefore,the blast performance of fabricated reinforced concrete superimposed beams is studied in this paper by combining experimental research and numerical analysis.The research results of this paper mainly include:(1)The material properties of the concrete samples and reinforcement reserved for the new and old concrete of the superimposed beam and the cast-in-place beam concrete are tested,and their mechanical properties parameters are obtained.(2)The foundation and shear wall are designed and manufactured as the test device for the explosion experiment of superimposed beams,which can better protect the experiment measuring instruments and ensure the reliability of the measured data.(3)Two superimposed beam specimens and one cast-in-place beam specimen were designed and manufactured,and explosion experiment were carried out on them under different working conditions.According to the experiment results,the failure model,the change and distribution of overpressure-time history curves,displacement-time history curves and strain-time history curves of the superimposed beam are analyzed and summarized.(4)The finite element software LS-DYNA is used to model the superimposed beam and cast-in-place beam,and the explosion experiment of the superimposed beam and cast-in-place beam is numerically simulated.The failure model and the change and distribution of the displacement-time curve of the test and numerical simulation are compared to verify the effectiveness and accuracy of the finite element model.(5)The verified finite element model is used to analyze the parameters of the blast performance of the superimposed beam,and the numerical simulation of the superimposed beam with different scaled distance,different strength of new and old concrete,different spans,different explosive equivalents and different pouring methods is carried out to study the change and distribution of its failure model and displacement-time history curves under different parameters.