Research On Seismic Behavior Of Brick Wall With Square Steel Tube Sand-Pebble Composite Ring Beam-Tie Column

China is a country with frequent earthquakes.Masonry structures must have seismic performance.Southwest China is the geographical region with the largest economic gap in the interior.Due to the economic development status,living habits,geographical environment and other influencing factors,agricultural houses in each region have gradually formed civil structure,wood structure,stone and wood structure,brick and wood structure and other types of traditional agricultural houses.Although China's residential building technology has been improved as a whole in recent years and entered the modern development period of the residential industry,due to the rural economy and culture in southwest China,rural houses are still constructed according to the traditional technology,resulting in insufficient seismic resistance and short service life of traditional rural houses in villages.After the Wenchuan earthquake,many rebuilt masonry buildings in villages and towns still have the situation of canceling or changing the setting of RC ring beam-column.The basic reasons are weak seismic awareness,complex construction technology and low construction quality,which hinder their application in rural areas.In view of the weak point of the masonry structure in the rural areas above,this paper uses the square steel pipe filled with sand and pebbles as the ring beam-tie column components,and forms the ring beam-tie column system on the basis of exploring the dense accumulation of sand and pebbles.The quasi-static test was carried out on this kind of ring beam-tie column brick masonry wall,supplemented by the relative ratio of plain wall and concrete ring beamtie column wall,and then the experimental study on this new ring beam-tie column was carried out to provide theoretical basis for its seismic performance.The main work of this paper includes the following two aspects:(1)according to the specific environment of rural areas,the feasibility of the new shape square steel tube sand pebble composite ring girder-tie column was demonstrated,and its theoretical design was completed.The theoretical design of square steel tube sand pebble composite ring beam-tie column was made into brick wall test pieces,and the blank brick wall and RC ring beam-tie column brick wall test pieces were made.(2)record wall damage in the test specimen,calculated by the experimental data,the seismic performance indicators,analysis reasons of specimen damage evaluation of sandy pebble combination ring beam,tie column filled square steel tubes and RC ring beam,tie column in the index,the advantages and disadvantages between sandy pebble filled steel composite ring beam,tie column shear bearing capacity calculation formula.The results show that compared with the plain wall,the failure mode of the ring beam-column confined wall with square steel tube and gravel combination is changed from brittle shear and friction failure to ductile shear and compression failure.Secondly,although the effect of load and stiffness degradation is not as good as that of RC ring beam-tie column restraint wall,the effect of sand-pebble composite ring beam-tie column restraint wall is not as good as that of RC ring beam-tie column restraint wall.However,in terms of ultimate displacement,ductility coefficient and equivalent viscous damping coefficient,sand-gravel composite ring beam-tie column restraint wall is superior to RC ring beam-tie column restraint wall.Finally,the calculation formula of the bearing capacity of the sand-pebble composite ring beam-column confined wall was presented.