Dynamic Response Analysis Of Top Isolated Structural Column Under Blast Loads

Worldwide,there occurred terrorist attacks and bombings,people in the vicinity of the explosion will occur source of accidental explosion caused casualties,but the blast wave propagation can also cause damage to the structural members,serious and even lead to the collapse of the whole structure of human life and property caused significant threat.In terms of the development of isolation structures,due to the good seismic performance of column-top isolation structures,they are more and more widely used in important buildings.Therefore,it is urgent to analyze the response of the column-top isolation structure column under the blast load,so as to reveal the failure mode of the top isolated structural column and provide a basis for the explosion-proof design of the column-top isolation structure column.The main research work and research results of this article are as follows:(1)Numerical simulations of natural rubber bearing isolation columns and leadcore rubber bearing isolation columns under explosive loads were performed,and the explosion resistance and response mechanism of natural rubber bearing isolation columns and lead-core rubber bearing isolation columns were analyzed.The results show that the main failure modes of the column top isolation structure column under explosive load are bending failure at the bottom of the column and tensile failure of the concrete at the back of the column.(2)The dynamic response difference between natural rubber bearing isolation column and lead-core rubber bearing isolation column under the blast load is compared and analyzed.The results show that the natural rubber bearing isolation column has a longer response time and a longer period.Due to the energy dissipation of the lead core of the lead rubber bearing isolation column,the balance can be quickly restored after the explosion load;the same explosion load The anti-explosion performance of the lower lead rubber bearing isolation column is better than that of the natural rubber bearing isolation column,but the difference of the damage degree is within 5%,indicating that the different bearing forms have a residual bearing capacity after the explosion of the isolation structure column limited impact.(3)The effects of factors such as the hardness of the rubber layer of the isolated bearing,the second shape factor,the compressive strength of the concrete axis,the hoop ratio and the reinforcement ratio were discussed.The results show that reducing the second shape coefficient of the bearing,the hardness of the rubber layer,and increasing the concrete axial compressive strength of the column-top isolation structure column and the ratio of the stirrup reinforcement can effectively improve the explosion resistance of the isolation structure column;The longitudinal reinforcement ratio has little effect on the anti-explosion performance of the isolated structure column.In the anti-explosion design of the isolated structure column,it is not necessary to specifically consider the longitudinal reinforcement ratio,and it only needs to meet the normal design requirements.(4)Simplified models of natural rubber bearing isolation columns and lead-core rubber bearing isolation columns are proposed respectively,and the simplified model and the solid model are compared.The results show that the simplified model can keep a good agreement with the solid model from the angles of column top displacement,column bottom shear force,column bottom bending moment,residual bearing capacity and concrete energy.The error range is within 10%,but the calculation efficiency is improved.It is 90%,and the simplified model can be used instead of the solid model in the column top isolation structure column explosion analysis,thereby improving the calculation efficiency.