Multi-dimensional Vulnerability Analysis And Vibration Control Optimization Design Research Of Multi-tower Structure

As the asymmetric layout and geometrically irregularity in the upper structure,the asymmetric multi-tower structure has complex dynamic characteristics.During its earthquake damage,serious shear-torsion coupling response will occur and needs to be considered in its vibration control.However,the traditional performance evaluation indicators such as inter-story displacement(angle)have limitations,and cannot evaluate the destructive state of shear-torsion coupling response of multi-tower structure,resulting in a mis-estimation of the seismic performance and safety threshold of such structures.Therefore,it is of great significance to develop a stochastic nonlinear vibration control and post-evaluation method for multi-tower structures.Relevant research works in this paper are as follow:(1)The modified Zhou-Hu power spectral density model is applied for Hartley orthogonal expansion of stochastic process.Combined with non-stationary intensity modulation,the non-stationary stochastic ground motion acceleration time histories under four types of site-soil characteristics are generated.Nonlinear response analysis of a frame structure under stochastic excitations and reliability analysis based on the probability density evolution method are carried out.It is found that the stochastic ground motion generated by the above method is reliable;site soil characteristics have a great influence on spectral characteristics of ground motion,the dynamic response of structure and the probability of the response.(2)The vulnerability curve of structural inter-story displacement angle performance limit state is solved.Fireworks Algorithm and Genetic Algorithm are adopted for the VED parameter optimization design of a VED-firame structure to reduce the stochastic dynamic response.Results show that VED consumes energy by increasing structural damping,whereas it parameter selection weighs on the damping effect;After optimization,the vulnerability curve of VED-frame structure declines and the seismic performance is improved;The optimization efficiency of Fireworks Algorithm in this example is better than Genetic Algorithm.(3)The vulnerability curve of a multi-tower structure based on inter-story displacement angle and inter-story torsion angle of multi-dimensional performance limit state is solved.TheFireworks Algorithm is improved with binary discretization and equal variable constraint for the BRB layout optimization design of a BRB-multi-tower structure system to reduce its stochastic shear-torsion coupling dynamic response.Results show that vibration control of torsional response of irregular multi-tower structure can also suppress its shear response to a certain extent.Chassis and conversion layers of multi-tower structure are the preferred layout stories for BRB vibration control.However,it is more recommended to adopt a damper arrangement scheme of"flexible energy dissipation"(which increases structural damping)for the vibration control of the tower upper structure.