Study On Axial Compressive Bearing Capacity And Its Mathematical Model Of Reinforced Concrete Members Damaged By Explosion

As the most basic load-bearing components in buildings,bridges and other engineering structures,reinforced concrete members are not only subject to traditional loads(such as dead load,live load,earthquake),but also may be subject to accidental loads(explosion,impact load,etc.)During their service period.When the explosion load is large,the structural damage of reinforced concrete members occurs,which leads to the decline of the bearing capacity of the specimens,inevitably affects the overall stability of the building,and even leads to the collapse of the building.Based on this,a physical model test method is proposed for reinforced concrete members in buildings subjected to contact explosion.A 1/4scale model of reinforced concrete columns is designed and manufactured,and explosion tests of different types of reinforced concrete columns are carried out,and the explosion damage of concrete columns is analyzed and counted.The relationship between damage factor and residual bearing capacity of reinforced concrete columns was analyzed,and the fitting curve between residual bearing capacity of reinforced concrete square columns and the amount of contact explosion was obtained.The main conclusions are as follows: The main conclusions are as follows:(1)The damage of reinforced concrete column is mainly impact compression damage,followed by tensile and spalling damage.With the increase of contact explosive charge,the damage range of reinforced concrete column gradually expands from the conical damage pit on the blast surface to the spalling damage of concrete cover on both sides of the specimen,and finally evolves into the damage of concrete and reinforcement cage in the core area;Increasing the blast face area,enlarging the section area and adopting a more symmetrical shape of reinforcement cage can significantly improve the anti-explosion ability of reinforced concrete columns.(2)The bearing capacity of the damaged reinforced concrete column decreases gradually with the expansion of the blast damage range.With the aggravation of the damage,the main bearing part of the damaged reinforced concrete column gradually changes from the core area concrete,the reinforcement cage and the concrete cover to the core area concrete and the exposed reinforcement cage,and finally to the central damaged core area concrete;The larger the reinforcement ratio and the cross-sectional area of the reinforced concrete column specimen are,the higher the bearing capacity of the damaged specimen is.(3)The curves of residual bearing capacity of RC square columns with different sizes subjected to contact explosion were obtained,and the prediction model of residual bearing capacity of RC square columns with arbitrary sizes subjected to contact explosion was established based on the empirical formula of size effect.