The Effect of High-Speed Fragment Impact on the Overall Strength of Concrete Columns Under Pressure Load

As a common engineering building material, concrete material is widely used in buildings, bridges, and protective structures. Concrete load-bearing columns are one of the main load-bearing components in buildings. In order to analyze the change rule of strength of plain concrete column under small size impact damage, the impact concrete test of 11 mm prefabricated tungsten alloy spherical fragment at different speeds was carried out, and the damage parameters of concrete were obtained. The numerical simulation was carried out with the concrete material model under the experimental strength. Based on the obtained material parameters, five initial variables of load (10–30 MPa), column side length (0.1–0.3 m), fragment velocity (500–1500 m/s), impact angle (0–45°), and position height (200–400 mm) were numerically simulated. Based on the action law of each variable on the concrete column, a comprehensive numerical calculation of orthogonal optimization with five variables and five levels was carried out. The calculation results show that the structural strength of concrete is mainly affected by the side length of the column, and the initial velocity of the fragment determines the size of the loss mass. The greater the load on the concrete column, the greater the height of the position, and the more easily the column collapses; when the side length of the concrete column reaches more than 250 mm, the fragment has little effect on the overall strength of the concrete column. Through the results obtained in this paper, it can be further extended to the evaluation of damage of building components under different loads, so as to obtain whether the bearing level of damaged concrete components can meet the requirements.