Dynamic Performance Analysis And Structural Condition Assessment Of Masonry Ancient Tower

As one of the ancient buildings in China,the masonry ancient tower has important cultural and artistic value.Due to the long history of construction,the structure has various damage states with increasing service life.Damage will inevitably cause changes in the stiffness,resulting in changes in the dynamic characteristics for the structure.For the ancient masonry tower,the research usually focuses on the architectural shape and dynamic performance of the structure itself,especially the non-destructive dynamic test of the structure.The modal information obtained from the dynamic test can be used for the vibration evaluation and damage identification of the pagoda,which is of great significance for the maintenance and reinforcement of the structure.Based on environmental incentive technology,the object of this paper is the Dingzhou Kaiyuan pagoda that is a masonry tower built in Song Dynasty.The on-site dynamic characteristics measurement was carried out and a test scheme suitable for solid tower ventricle-like ancient towers was proposed.And based on this,the main contents include the following aspects:First,according to the structural characteristics and the research status of modal recognition methods based on environmental incentive technology at home and abroad,the original signal is preprocessed and time-frequency domain analyzed to obtain the basic modal parameters of the structure.Secondly,based on the results of the modal parameters,the finite element model is established by ABAQUS.In addition,through the iteration of the basic model parameters and the model update considering the current structure,the revised numerical model was adjusted.The revised numerical model is in good agreement with the measured results from the three aspects of frequency,mode coefficient and the trend of the mode diagram.The obtained numerical model can be used as the basis for subsequent structural dynamic response analysis.Finally,a simplified analysis model of the structure is established,combining with the analysis results,the interlayer stiffness values,modal participation rates,stiffness center distribution and flexibility curvatureamplitude mutation coefficients of Kaiyuan pagoda are calculated to assess the damage status of the structure.Based on the research contents of Kaiyuan Temple Pagoda,this paper conducted a structural status analysis of the ancient pagoda,and used fuzzy comprehensive analysis method to evaluate the structural condition of each layer of the ancient pagoda.It has a certain reference value for the study of the same type of masonry ancient tower.59 diagrams,39 charts,104 references.