Research On Dynamic Response Of High-rise Shear Wall Structures Caused By Attached Tower Crane

Since the beginning of the 21st century,with the continuous breakthrough of China’s economic aggregate,the pace of urbanization is getting faster and faster,and a large number of people have converged into large and medium-sized cities.In order to meet the housing needs of the urban population,a large number of urban villages have been transformed into modern high-rise residential buildings.In the current design process of high-rise residential buildings in China,only the dead load,live load,wind load and seismic load are considered while the construction load during the construction process is rarely considered.However,the strength of the main building has not reached the design strength during the construction process,the damage of the construction load at this time cannot be ignored.The most significant and inevitable is the tower crane dynamic load influence on the main structure.Therefore,it is necessary and important to study the response especially the dynamic response of the high-rise structure under the tower crane construction load.This thesis takes the reconstruction project of a village in Dongxihu district of Wuhan as the project background to study the dynamic response of the high-rise shear wall structure caused by the tower crane lifting process and propose some effective engineering measures to suppress the dynamic response and finally provide reference and guidance for similar practical projects.The dynamic response of the main structure under the construction load of the tower crane is closely related to the natural vibration characteristic of the structure itself.According to the actual engineering design drawings,ANSYS finite element software was used to take modal analysis on the 33-layer shear wall structure(capped state),the23-layer shear wall structure(engineering accident state)and the 23-layer with tower crane attached state to judge the rationality of the shear wall structure design.The operation modal test of the 33-layer shear wall structure was carried out with the equipment of B&K company to verify the correctness of the finite element model and enhance the credibility of the subsequent transient dynamic analysis of the tower crane lifting process.In order to reflect the characteristics of the tower crane construction load as a dynamic load,this thesis proposes to measure the acceleration of the lifting object by field test and applied the acceleration time function based on test in the finite element analysis.Compared with the traditional static equivalent method,this method can reflect the dynamic response characteristics of the structure and the results are more accurate and reliable.The frequency spectrum of the collected acceleration time domain data is obtained by fast Fourier transform(FFT).It is found that it contains low-frequency component and is very close to the corresponding frequency of the torsional mode of the 23-layer structure.It is concluded that structural resonance is easy to occur.It can be seen from the results of transient dynamics analysis that the maximum displacement at the top of the structure is consistent with the monitoring results during construction.The maximum acceleration at the top exceeds the limit specified in the relevant regulations,which causes a strong response of the structure and the significant sense of shaking of the internal construction personnel.The torsional characteristics of structural deformation show that the dynamic response is closely related to the torsional mode.It is proved that the dynamic response of the shear wall structure caused by tower crane construction load is serious.In order to solve the problems of serious dynamic response of shear wall structure caused by the construction load of tower crane,affecting the progress of the project and existing serious safety hazards,this thesis carries out the theoretical analysis on the simplified mechanical model of the actual project.The calculation results show that reducing the stiffness of the connecting rod attached to the wall can reduce the frequency of the bending mode of the whole structure.However,the theoretical analysis cannot be applied to the calculation of the torsional mode.Therefore,through the finite element modal analysis,it is proved that reducing the stiffness of the connecting rod attached to the wall can also reduce the torsional mode frequency and achieve the purpose of stagger the low frequency component of the lifting acceleration.The dynamic response of the shear wall structure caused by the lifting process of the tower crane in different positions is also simulated.The strength of structural response caused by dynamic load at different positions is evaluated which provides reference and guidance for restraining the dynamic response of main structure caused by tower crane in the construction of the similar type of project to ensure the safety of the actual project.