Study On Axial Compression Performance Of Self-compacting Concrete Shear Wall With Multi-cavity Steel Tube

The multi-cavity concrete-filled steel tube shear wall can be arranged in cross-sections such as I-shaped,L-shaped or T-shaped according to the architectural design.It has the advantages of flexible structural layout,improved female angle,higher bearing capacity,good plasticity and convenient construction.This structure can give full play to the mechanical properties of steel tubes and self-compacting concrete(SCC).The concrete is under a three-way stress state under the tight hoop of the encased steel tubes,which significantly improves its strength and toughness performance;the internal filling of the steel tubes The concrete can delay or prevent premature local buckling of the outsourcing steel pipe.At present,the axial compression performance test and bearing capacity calculation theory of multi-cavity steel pipe self-compacting concrete shear wall are not perfect,which limits its application and promotion in construction engineering.Based on the reconstruction project of Hongxinyuan urban shanty town in Hongguang Town,this paper studies the axial compression performance of the multi-cavity steel pipe self-compacting concrete shear wall using the method of experiment and finite element,and analyzes the synergy and failure mechanism of steel pipe and concrete The paper proposes the calculation theory and design method of the bearing capacity of the I-shaped multi-cavity steel tube self-compacting concrete shear wall and the T-shaped multi-cavity steel tube self-compacting concrete shear wall,which provides calculation theory and technical support for similar engineering design.The main research contents of this paper are as follows:(1)Design the mix ratio of C40 SCC,and study the working performance and mechanical properties of SCC.The mechanical properties of SCC are evaluated through compression test,triaxial shear test and split tensile test.A formula for compressive strength of low content fly ash silica fume SCC is proposed;the performance of SCC is evaluated by two performance indicators,slump expansion degree and expansion time T500.The model equation of the relationship between ultrasonic amplitude and compressive strength was obtained through ultrasonic nondestructive testing of SCC,which can provide a reference for the design of SCC mixture ratio with fly ash and silica fume.(2)This paper designs and conducts axial compression tests of three I-shaped multi-cavity steel tube self-compacting concrete shear walls and three T-shaped multi-cavity steel tube self-compacting concrete shear walls with different numbers of cavities.The stress failure process and failure form of self-compacting concrete-shear wall with cavity steel tube,the load-displacement relationship curve and bearing capacity of self-compacting concrete-shear wall with multi-cavity steel tube are obtained.(3)The finite element model of three I-shaped multi-cavity steel tube self-compacting concrete shear walls and three T-shaped multi-cavity steel tube self-compacting concrete shear walls are built using large-scale finite element software ABAQUS.Based on the results of ABAQUS finite element calculation,the section stress distribution law of multi-cavity steel tube self-compacting concrete shear wall under axial compression load and the mechanism between concrete and multi-cavity steel tube under axial compression load were analyzed.(4)Establish 18 finite element models of 18 ?-shaped multi-cavity steel tube self-compacting concrete shear walls and 18 T-shaped multi-cavity steel tube self-compacting concrete shear walls.The effects of different parameters on the axial compression properties of I-shaped multi-cavity steel tube self-compacting concrete shear wall and T-shaped multi-cavity steel tube self-compacting concrete shear wall were studied.Specific parmeters include concrete strength,steel yield strength,steel content ratio,etc.The influence law of I-shaped self-compacting concrete shear wall and T-shaped self-compacting concrete shear wall under axial load is obtained.Based on the analysis results,a formula for calculating the bearing capacity of the self-compacting concrete shear wall with I-shaped multi-cavity steel tube and the self-compacting concrete shear wall with T-shaped multi-cavity steel tube is proposed.