The Seismic Bearing Capacity Reliability Analysis Of L-shaped RC Columns Considering Variability Of Eccentricity And Material Constitutive Parameters

In traditional frame structure,the column section is generally rectangular,and the four corners in the small rooms of residence and office will show edges and corners.In practical engineering,L-shaped columns are widely used in most frame structures for the sake of beautiful layout and convenient use.However,due to the characteristics of L-shaped column,the complexity of design and calculation and the lack of unified design basis,the popularization of L-shaped column structure system is limited.For reinforced concrete L-shaped columns,they are usually corner columns in the structure,and their section forms are not completely symmetrical,and they are often in two-way eccentric compression state.The neutral axis of the section is not perpendicular to the bending moment action plane,nor parallel to the section edge.At present there is a lack of extensive research on the bearing capacity reliability of L-section two-way eccentric members at home and abroad.In this paper,considering the variation of material parameters and the random factors of eccentricity,the influence of bearing capacity variation of L-shaped columns and the reliability of seismic bearing capacity are studied and analyzed(1)81 groups of material constitutive parameter data are collected,and the correlation between material constitutive parameters is investigated.The correlation transformation matrix between constitutive parameters is established through analysis.The concrete compressive strength fc,concrete peak strain ε0 and εcu are taken as the related random variables by MATLAB for 100 groups of sampling,and 100 groups of material sample points are obtained.(2)select 0°-45° as the loading angle range of L-shaped column,and calculate the bending capacity when the axial compression ratio is 0.3,0.4,0.5,0.6 and 0.7 respectively.The results of 3000 groups of flexural capacity are compared and analyzed,and the change of flexural capacity of L-shaped column under different loading angle and different axial compression ratio is summarized.Through fitting,the change of bearing capacity is obtained by mathematical equation.(3)considering the random characteristic of biaxial eccentricity,the reliability of L-shaped RC biaxial columns under different characteristic parameters is analyzed.Different load effect ratios are selected as the characteristic parameters of reliability analysis.Taking an 8-story frame structure with L-shaped columns as an example,the design axial force and design bending moment are obtained through ETABS analysis,and then the reliability of seismic bearing capacity of columns with different characteristic parameters is calculated by self programming.