Dynamic Behavior Of Reinforced Concrete Filled Steel Tubular With Axial Force Under Impact Load After Fire

Reinforced steel tube concrete member has many advantages such as high bearing capacity,good fire resistance,convenient construction and so on.It is widely used in highrise buildings.Fire is a relatively common disaster.And fires are often accompanied by explosions.The explosion will produce a lot of debris which have speed and quality.When the column is hit by these debris,its bearing capacity will be reduced or even lost.This will cause serious damage to the building.It also has a bad effect on people's safety.In order to ensure the safety of people's life and property,it is necessary to analyze the impact performance of the building components,especially the columns after fire.At present,only a few scholars have studied the impact resistance of ordinary steel tube concrete members after fire.However,the study on the impact resistance of reinforced concrete filled steel tube after fire is not reported.The research object of this paper is reinforced steel tube concrete member.ABAQUS was used to build the component model.And the simulation of the fire and the impact after fire is done.The main research contents of this paper are as follows:(1)The literatures on fire and impact of reinforced concrete filled steel tube are reviewed.Find proper constitutive relation and related parameters such as thermal parameters of materials and mechanical parameters.On this basis,establish the model according to related experiments.The rationality of parameter selection is obtained.(2)Select the appropriate heating curve and heat transfer equation.The reinforced concrete-filled steel tubular column model is established.The distribution of temperature field is obtained by fire simulation.(3)The mechanical properties of the heated reinforced concrete filled steel tubular columns under impact load are analyzed.The impact process is illustrated by impact,deflection and energy conversion.The residual bearing capacity of the column is studied.(4)The related parameters are analyzed,such as the length ratio,impact velocity,impact position,temperature and reinforcement ratio.The mechanical properties and failure modes of reinforced concrete filled steel tube are analyzed in terms of energy,impact and deflection.