Study On Anti-explosion Performance Of High Strength H-shaped Steel Concrete Column Under Blast Loading

In recent years,there have been more and more structural damage and even house collapse accidents due to explosions,especially high-rise buildings and super high-rise buildings damaged by explosions,bringing great safety risks to people’s lives and property safety.High-strength steel-reinforced concrete column members are widely used in high-rise and super high-rise buildings due to their advantages of large bearing capacity and good seismic performance.However,so far,the research results on dynamic response and damage of high-strength steel-reinforced concrete column are relatively few.Therefore,the dynamic response and damage mechanism of high-strength steel-reinforced concrete column under the influence of explosion load are discussed.It has key theoretical value and practical significance.In this paper,ANSYS/LS-DYNA software is used to analyze the mechanical performance of high-strength H-shaped steel concrete column under explosion load,and study the dynamic response,failure form and damage effect of high-strength H-shaped steel concrete column under explosion load.The effects of different parameter variables（proportional distance,slenderness ratio,steel content,diameter of longitudinal reinforcement,strength of section steel,height of explosion source from ground,etc.）on the anti-explosion performance of high-strength H-shaped steel concrete column under explosion load are clarified,and the damage degree of high-strength H-shaped steel concrete column is studied and analyzed.The results are as follows:（1）The explosive was simulated to explode in free air,and the peak overpressure simulation values at different proportional distances were obtained.The simulation values were compared with the calculated values obtained from the empirical formula to verify the rationality of the selection of explosive and air parameters.By simulating the explosion model of reinforced concrete beam in air,the error between the deflection curve of reinforced concrete beam under explosion load analyzed and the deflection curve obtained by experiment is within a reasonable range,which verifies the feasibility of the element type,material constitutive relation and analysis algorithm of the finite element model of high-strength H-section steel concrete column in this paper.（2）The dynamic response and failure mode of high-strength H-shaped steel concrete column under explosion load are simulated by the fluid-structure coupling calculation method.The results show that the stress and strain values of the web at the two ends of H-beam are greater than those in the middle of the column.Under the condition that the proportional distance is Z=0.26m/kg^1/3,the failure modes of high-strength H-shaped steel concrete column are divided into three types:the bending failure occurs mainly in the middle of the column,the shear failure occurs at the top and bottom of the column,and the bending shear failure occurs in the 1/4 and 3/4 height range of the column.（3）Through the method of parametric analysis,the influences of various parameter factors（proportional distance,slenderness ratio,steel content,diameter of longitudinal reinforcement,strength of section steel and height of blast source from column bottom）on dynamic response and failure form of high-strength H-section steel concrete column under explosion load were clarified.The results show that,under the same blast load,the anti-knock performance of the column can be improved significantly by increasing the proportion distance,steel content,diameter of longitudinal reinforcement and strength of section steel.The anti-knock performance of the column decreases with the increase of slenderness ratio.When the explosion source explodes in the middle of the column,the deformation of the column is the largest.When the location of the explosion source gradually moves toward the end of the column,the deformation degree of the column gradually decreases,and the location of the maximum displacement gradually moves toward the end of the column.（4）Based on overpressure-impulse damage assessment criteria,the dimensionless parameterθis taken as damage assessment parameter of the high-strength h-shaped steel concrete column.The overpressure-impulse curve（P-I curve）of h-shaped steel concrete column is obtained by numerical simulation,and the damage degree of the column is divided into three levels:mild damage,moderate injury and severe damage.