Vertical Impact Load Of Concrete Structural Floor Panel The Simplified Calculation Method Under The Action Of Impact Coefficient

It is easy to be a great damage for the impact load with huge energy in a short action time.The accidents frequently occur that the impact of high falling objects to the concrete construction building(house)panels.Generally,the accidents are not taken into consideration in developing the construction design for the low chance reason.So it is an important topic in the field of evaluation,testing and strengthen about how to get the exact analysis and calculate the influence that high falling objects bring to the building.This thesis bases on a residential building accident due to the break of a tower crane in Zhuzhou,Hunan Province and a comprehensive summary and conclusion of the home and abroad existing issues about the method for calculating.It represents a simplified calculation method of impact for slab with concrete structure under vertical impact load through simplifying and approximating according to the situation.The main contents and achievements of this thesis are as follows.(1)By carrying out a systematic summary and conclusion of the existing calculation theory and method for impact problem and the damage mechanism of structure under the effect of impact load at both home and abroad,the conclusion is that energy method is the theoretical basis for solving the impact problems.To lay a theoretical foundation for solving the impact problem by energy method.(2)Based on Rayleigh method and Rayleigh finite element method,by simplifying and approximating the boundary constraints and the maximum deflection position of concrete building(house)panels,a simplified method of calculating the impact coefficient of the plate under impact loading is proposed.(3)A structural model of single frame concrete floor(roof)panel structure model is established by using general finite element software SAP2000.For the plate with symmetrical confinement boundary,a rod plate method,Rayleigh finite element method and the simplified method proposed in this paper are used to calculate the maximum static deflection and impact coefficient of the plate,the correlation between the mass of the impact object,the height of the impact object and the impact coefficient is obtained.The results show that for the plate with symmetric confinement boundary,the impact coefficient calculated by the simplified calculation method proposed in this paper is very close to that calculated by the Rayleigh finite element method,and the result calculated by rod method is relatively with a large deviation to that calculated by the Rayleigh finite element method.(4)Based on the engineering background of the tower crane tower body breaking accident in the city of Zhuzhou,Hunan Province,the influence range and influence degree of the top plate of the tower crane counterweight falling impact basement roof are analyzed by the simplified method,and the technical support is provided for the accident treatment.