Study On Synergistic Mechanical Performance Of Autoclaved Aerated Concrete Filled Wall And Steel Frame Structure

Numerous seismic disasters have shown that the seismic damage caused by infill wall frame structures poses a great safety threat to people.During earthquakes,the complex interaction between infill walls and frames is extremely disadvantageous to the seismic resistance of the structure.With the proposal of seismic resilience,researchers have paid more and more attention to the performance level of various structures during and after earthquakes.This paper investigated the synergistic mechanical performance between autoclaved aerated concrete(AAC)infill walls and steel frame structures through vulnerability analysis,pseudo-static test research,and ABAQUS finite element calculation.The main work and conclusions are as follows:(1)Fifty-seven pseudo-static test data of single-span fully masonry-filled infill wall frames were collected to analyze and compare the vulnerability of AAC-type new masonry blocks,hollow blocks,and solid clay bricks filled in the plane of the infill wall under rigid and flexible connections.The results show that the flexible connection of AAC-type new masonry block infill walls has significant seismic performance under small and medium earthquakes and can avoid premature failure of the wall and endanger safety during large earthquakes,making it the preferred means to achieve collaborative performance between masonry-filled walls and frames.(2)Pseudo-static tests were conducted on three 1:2 AAC infill wall steel frame structures to study and compare the seismic performance of structures and the failure process of walls under flexible and rigid connections.The results show that the maximum bearing capacity under flexible connection is not much different from that under rigid connection,but the other seismic performance indicators are significantly improved.The wall had almost no significant changes in the loading process from θ = 1/225 to 1/53,except for a diagonal crack during the loading displacement angle θ = 1/315.After providing lateral stiffness in the subsequent loading process,slight damage appeared,significantly reducing the initial stiffness contribution of the wall to the frame and exhibiting excellent wall-frame collaborative working performance compared to rigid connection walls.(3)The combination of finite element and orthogonal design methods was used to analyze the influence of four factors on the seismic performance indicators of flexible connection AAC infill wall steel frame structures,from high to low: reserved seam width,spring stiffness,high-span ratio,and axial compression ratio.(4)Increasing the axial compression ratio leads to a downward trend in all seismic performance indicators of the structure.Increasing the seam width between the wall and the frame can improve the yield displacement and peak load of the structure but significantly reduce the initial stiffness and require an improvement in ductility.Reducing the spring stiffness lowers the initial stiffness,ductility,and peak load of the structure but increases the yield displacement.Reducing the high-span ratio improves the initial stiffness,yield displacement,and peak load of the structure but weakens the ductility.The four factors have different effects on cumulative energy dissipation.(5)The recommended value for the seam width between flexible connection AAC wall frames is around 40 mm,and the stiffness of the filling material between seams should be between 100 ～ 500 N/mm.At the same time,attention should be paid to the tensile connection between the wall and the frame under flexible connection to avoid secondary seismic damage.