Study On Seismic Response Of Single Open House Based On Different Incident Angles Of Seismic Waves

Houses in rural areas of our country are generally self-built buildings with informal design and construction.They are the engineering groups that suffer the most serious damage,the largest number of casualties in previous earthquakes.Since the Wenchuan Earthquake,the Yushu Earthquake,Lushan Earthquake and Ludian Earthquake,which occurred in recent years,caused serious damage to farmhouses.After Lushan Earthquake,the research team found many times that the earthquake damage of single-bay masonry buildings near streets was very serious,and the characteristics of torsion and collision damage were remarkable.As a common form of construction in Sichuan rural area,single-open farmhouse with street-facing transportation is convenient,with commercial and residential functions,and widely exists because of its cost-effective performance.Self-built farmhouses destroyed repeatedly by earthquakes,resulting in huge burdens that make it difficult for farmers to get rid of poverty for a long time,which is the current situation of rural buildings in China.It is an urgent need for the construction of villages to prevent the earthquake disasters in rural areas.In view of this,this paper focuses on the torsional vibration response of single-open farmhouse.The main research contents and results are as follows.(1)Based on the investigation of earthquake damage in Lushan,random construction of single-bay masonry farmhouse near the street and serious deviation between the center of mass and rigidity are the main causes of torsional damage.At the same time,the adjacent farmhouse is built with small adjacent spacing,which is far from meeting the requirements of the seismic joints in the standard design,and the collision results in intensified torsional vibration and structural damage.(2)The simplified analysis model of the serial strip model was constructed to form the differential equation of motion.Three variants of Takeda's model was selected to simulate the cracking and yielding process of the masonry structure.Completion of the elastoplastic analysis program considering the flat-twisted coupling masonry is called DKPG.The scientific rationality of the program was verified by the comparison test of the shaking table test structure of the single-opening farmhouse.(3)The lateral stiffness of a single-bay farmhouse in the depth direction is greater than that in the opening direction,resulting in a smaller dynamic response in depth driection.Increasing the lateral stiffness of the opening and the depth direction reduces the dynamic response amplitude by about 10% and 50%,but the dynamic response amplitude narrows to about 1% and 20% when the stiffness continues to increase,which indicates that the increase of depth and the opening has limited influence on the dynamic response in their respective directions.(4)Under the action of earthquake,the opening of the structure increases,resulting in a 39% increase in dynamic response amplitude of the house's direction of depth.Degradation of bearing capacity and stiffness with one side may affect the ability of bearing capacity and stiffness in the other direction.Therefore,increase of the seismic capacity of the weak side can significantly enhance the seismic performance of the single-open farmhouse.(5)Judging from the change of the dynamic response amplitude of torsion angle,the influence of structural stiffness and layer number on torsion angle response is less than that of angle of seismic wave.When the opening or depth of single-bay farm house increases,the lateral component is far away from the rigid center,and the torsional stiffness is increased,so that the torsional angle of the structure decreases,but the effect is confined.(6)The abrupt change zone of vertical stiffness has a great influence on the dynamic response of the structure.The single-bay farm house structure is not conducive to earthquake resistance.When the farmhouse is flexible on the top,the dynamic response of the structure increases by less than 30%.It shows that the plastic deformation time of single-bay farmhouse is delayed.Therefore,it is suggested to adopt the method of "rigid bottom and soft top" in the construction of the farm houses,which is beneficial to earthquake resistance.(7)When the incident angle of the seismic wave is fixed,only the number of floors changes,and the structural dynamic response increases first and then decreases.Because of the increase of floors,the overall lateral stiffness of the single-opening farmhouse is weakened,and the structural response is increased.The third-layer dynamic response is simulated and recorded.As the number of layers continues to increase,the stress of the third layer is increased by the gravity of the upper floor,and its dynamic response is suppressed.