In-Situ Testing Of Dynamic Characteristics And Seismic Response Analysis Of Hua E Xiang Hui Lou Of Xingqing Palace In Xi’an

Hua E Xiang Hui Lou located in Xingqing Palace in Xi ’an is a modern traditional building with a mixture of brick and wood as its structural features.Accurate evaluation of structural characteristics and seismic performance is of great significance for the research and protection of such building structures.The particularity of the brick-wood structure determines that its complexity and dynamic characteristics are different from other structural forms.Therefore,this paper adopts the method of in-situ testing of dynamic characteristics and finite element simulation to study its dynamic characteristics and seismic response law,and carries on the seismic vulnerability analysis.The research results provide an important reference for the protection of the mixed structures of brick and wood such as Hua E Xiang Hui Lou.The main research work of this paper is as follows:(1)The dynamic characteristics of Hua E Xiang Hui Lou were tested in situ under environmental excitation,and the real-time pulsation response signals of each layer’s capitals and column roots of Hua E Xiang Hui Lou were collected and analyzed in time domain and frequency domain.The dynamic characteristics of Hua E Xiang Hui Lou were obtained by peak picking method.(2)Hua E Xiang Hui Lou model was established the mixed structure model of brick and wood and the model of wood structure.by using finite element software Etabs.In modeling,frame element is used to simulate the beam and column.The shell element is used to simulate the masonry wall,and the connection between the masonry wall and the foundation is simplified into rigid connection.During roof simulation,roof weight is applied to timber purlins in the form of distributed load.Wire spring element is used to simulate tenon-kung and dougong.(3)The modal analysis of the brick and wood structure model and the model of wood structure is carried out respectively.The accuracy of the model is verified by comparing the simulation results with the in-situ test results.The results show that the vibration modes of the first six orders of the two models are similar.The first two orders are horizontal translational vibration,the third order is torsional vibration around vertical vibration,the fourth order is the dislocation translational vibration of the first and second floors of the east-west structure,the fifth order is the dislocation translational vibration of the first and second floors of the north-south structure,and the sixth order is the combined vibration of torsion and translational vibration.The modal contribution of the two models is analyzed.The total mass participation coefficient of the first eight modal forms of the brick and wood structure is more than 90%,and the total mass participation coefficient of the first two modal forms of the wood structure is more than 90%.The vibration sequence of the two models is in line with the general vibration sequence of the structure,which proves that the building layout of the calyx phase is reasonable.The seismic response analysis of Hua E Xiang Hui Lou can be carried out.(4)The time-history response of the brick and wood model of Hua E Xiang Hui Lou is analyzed.The results show that the displacement response of the structure increases with the increase of earthquake intensity.The maximum interstory displacement Angle of Hua E Xiang Hui Lou is 1/155,which is less than the limit value of 1/50 for the elasticplastic interstory displacement Angle of the upper and lower mixed wood structure buildings stipulated in the Technical Standard for Multi-tall Wooden Structure Buildings.Under the same seismic wave,the acceleration response of the structure from the first floor to the roof gradually increases,and the dynamic coefficient of the structure is less than 1.(5)A comparative analysis of the seismic response results of brick and wood structure model and wood structure contrast model is presented.The results show that the bottom masonry structure can reduce the displacement response and acceleration of the whole structure.The reason for this difference is that the one-story masonry structure enhances the lateral stiffness of the whole structure,thus reducing the displacement response and acceleration response of the whole structure,and significantly improves the stability and seismic performance of the structure.In addition,under the same working condition,the floor shear of the mixed structure of brick and wood is greater than that of the wooden structure,because the mass and stiffness of the structure of brick and wood are larger than that of the wooden structure,and the floor shear generated by the earthquake is also larger.(6)IDA based seismic vulnerability analysis of brick and wood structure of Hua E Xiang Hui Lou was carried out.The results show that Hua E Xiang Hui Lou not only meets the requirements of three levels in the 8 degree zone,but also from the point of view of seismic vulnerability failure probability analysis,although the structure will be slightly damaged during small and medium earthquakes,it can be repaired and has no influence on the stability of the structure.A large earthquake will cause moderate damage to some buildings.Although the structure has suffered some damage at this time,it has little impact on the structure as a whole.Therefore,Hua E Xiang Hui Lou seismic performance is good,has far met the requirements of the earthquake does not fall.