Research On Mechanical Properties Of Recycled Steel Tube Recycled Concrete Eccentrically Loaded Columns At Room Temperature And High Temperature

The new composite structure of steel tube recycled concrete columns not only improves the bearing capacity of steel and recycled concrete,but also makes full use of recycled concrete,reduces the use of natural resources,and provides a new way for the treatment of waste concrete Technical means.Domestic and foreign researches mainly focus on the research of concretefilled steel tube columns under axial compression,and there are few researches on the eccentrically compressed steel tube columns under high temperature.Based on existing experiments,this paper uses ABAQUS finite element software to establish a model to study the mechanical properties of circular steel tube recycled concrete eccentrically compressed columns at room temperature and high temperature,The main research contents are as follows:Establish a model of an existing test specimen at room temperature,perform an axial compression test simulation on it,compare the simulation results with the existing test results,and verify the validity of the model;on this basis,establish a recycled concrete steel tube at room temperature Biased column model,its mechanical performance analysis.Explore the influence of different recycled concrete replacement rate,eccentricity,slenderness ratio,steel content and other parameters on the ultimate bearing capacity and initial stiffness of circular steel tube recycled concrete eccentric compression columns.The results show that the slenderness ratio has a certain effect on whether the component is large or small under eccentric compression;the replacement rate of recycled concrete has little effect on the ultimate bearing capacity and initial stiffness of the component;the increase in the slenderness ratio will lead to the ultimate bearing capacity and the initial stiffness of the component.The initial stiffness is reduced;the greater the eccentricity,the lower the ultimate bearing capacity and initial stiffness of the component;the ultimate bearing capacity and initial stiffness of the component increase with the increase of the steel content and the strength of the recycled concrete;the modified round steel pipe is recycled Calculation formula for bearing capacity of concrete columns under eccentric compression.The mechanical properties of recycled steel tubular recycled concrete columns under high temperature are studied,and the effects of different fire time,different eccentricity,recycled concrete replacement rate,slenderness ratio,steel content,recycled concrete strength,fire time and other parameters on high temperature The influence of the eccentric compression performance,ultimate bearing capacity and initial stiffness of the lower round steel tube recycled concrete column.The results show that the mechanical performance of the circular steel tube recycled concrete short column under high temperature is greatly reduced,especially the effect on the mechanical performance of the member in the elastoplastic stage;the circular steel tube recycled concrete long column under high temperature The mechanical performance is greatly reduced,and the impact on each stage of the component is basically the same.Compared with the normal temperature,the position of the component bending point is reduced by about 1/6 column height;The greater the replacement rate of recycled concrete,the lower the ultimate bearing capacity and initial stiffness of the component.At high temperatures,the replacement rate of recycled concrete has a greater impact on the initial stiffness of the component;the greater the slenderness ratio,the greater the ultimate bearing capacity and initial stiffness of the component.Low,at room temperature,the slenderness ratio has a greater impact on the initial stiffness of the component;the greater the eccentricity,the lower the ultimate bearing capacity and initial stiffness of the component,and the eccentricity has a greater impact on the initial stiffness of the component at room temperature;steel The higher the ratio and the strength of recycled concrete,the greater the ultimate load-bearing capacity of the component.The initial stiffness of the component increases with the increase of the steel content and the strength of the recycled concrete,which has a greater impact on the initial stiffness of the component at room temperature.The coefficient of fire time t is introduced,and the formula for calculating the bearing capacity of circular steel tube recycled concrete columns under high temperature is introduced.