Study On The Oblique Seismic Performance Of Reinforced Concrete Special-shaped Column

Due to the increasing demand for the aesthetics,comfort,and internal spatial layout of housing,special-shaped column structures have gradually become a popular structural form.However,as a new thing,this structural form still requires a complete theoretical foundation.Relevant experts and scholars have conducted seismic damage investigation and research on the damage status of special-shaped column frame structures under major earthquake actions.According to the analysis of seismic damage data,one factor that causes strong beams and weak columns during earthquakes is that the current seismic design standards in China do not consider the arbitrary and multidimensional characteristics of ground motion.The direction of ground motion input and the direction of the horizontal axis of the structure form a certain angle,and special-shaped columns need to withstand oblique seismic effects,The floor slab has a certain strengthening effect on the strength of the beam,resulting in the diagonal bearing capacity of special-shaped frame columns not meeting the requirements of "strong columns and weak beams".Any direction on the plane can become the most unfavorable direction for earthquake action,therefore,ensuring seismic performance of buildings only in the two main axis directions is not safe.At present,there is no unified specification for the reinforcement of structural components with special-shaped columns in China.Further in-depth research is needed on the new reinforcement methods and the oblique seismic performance of special-shaped columns after reinforcement.There is currently little research on the oblique seismic performance of reinforced concrete special-shaped columns in oblique seismic motion.The main research work of this article is as follows:(1)In this thesis,three new constraint reinforcement methods and their reinforcement schemes are designed,including local reinforcement of reinforcement mesh,embedded CFRP Flat noodles at the column end and embedded CFRP plate at the column end.With the loading angle and the new constraint reinforcement method as variables,12 reinforced concrete cruciform column specimens and 6 reinforced concrete L-shaped column specimens are designed.(2)This article demonstrates the correctness of the finite element modeling method based on seismic performance indicators such as failure state,hysteresis curve,characteristic bearing capacity,and displacement.Based on this,oblique low cycle reciprocating loading simulation was conducted on the specimens,analyzing the seismic performance indicators such as failure state,hysteresis and skeleton curve,characteristic bearing capacity,characteristic displacement,and energy dissipation performance.A comparative study was conducted on the oblique seismic performance of unreinforced and reinforced specimens,The effectiveness of the new constraint reinforcement method in terms of oblique seismic performance has been clarified.(3)This article proposes a formula for calculating the compressive and bending bearing capacity of reinforced concrete cross shaped columns and L-shaped columns under a new type of constraint reinforcement method.(4)This article uses the finite element software ABAQUS to simulate the seismic performance of reinforced concrete cross shaped columns.By changing the influencing parameters,52 sets of specimen data were obtained.The 52 sets of data were imported into MATLAB to establish BP network prediction models for multi-objective input,single objective output,and multi-objective input and output,respectively,Predicted the horizontal peak bearing capacity of reinforced concrete special-shaped columns under the influence of multiple factors and designed the reinforcement of reinforced concrete special-shaped columns.On the basis of the established prediction model,the influence of relevant factor parameters on the horizontal peak bearing capacity of reinforced concrete special-shaped columns was analyzed.