Design Analysis And Application Of Large-span Complicated Cross Connected Structures

With the appearance of new types of high-rise building structures,complex connected structures have emerged as a new type of structure that has enriched the public’s view.Combining thestatus quo of the actual application of complex high-rise building structures at home and abroad,and considering that there has been insufficient researches on paper deals with the research on the overall seismic performance of diagonally long-span complex connected structures and the oblique large-span structures that have less energy dissipation andare relatively more sensitive to response.This article proposes the use of the characteristics of the base and the connected structure itself,making the complex connected structure itself more energy-saving and shock-absorbing than the two main towers.By increasing the passive energy-consuming capacity of the structure itself,the response of the long-span oblique asymmetric complex connected structure to earthquake action is reduced.In this paper,the finite element analysis software MIDAS/GEN is used to build a three-dimensional space model of a large-span diagonally-consistent complex high-rise building structure.According to the characteristics of the structure,the seismic response analysis of the individual modeling and the overall modeling is first performed.Three different types of base connections have been adopted,and the impact of the connection of the comparative bearings on the overall seismic effect of the structure has been carried out.For the energy dissipation of asymmetric structures,the combination of a viscoelastic damper with an elastic sliding bearing is selected.By changing the damping coefficient and the spring stiffness of the viscoelastic damper,the elastic time history analysis of the structure under multiple earthquakes is performed.Comparing the viscoelastic dampers under different parameters makes the overall structure have the least response to earthquakes.Finally,a rare earthquake verification is performed.The elastic-plastic time history analysis of a large-span complex connected structure with elastic sliding visco-elastic composite performed.Analyze the response of the structure to the earthquake under the action of a rare earthquake.Conclusions are as follows:(1)Analyze the modal changes of the single tower and the overall structure of this asymmetrical complex connected structure connected by a long span connector,It is found that the period of self-vibration of the structure is extended.With the inter-layer displacement angle,the overall modeling is reduced compared to modeling alone.Among them,the overall X-directional seismic modeling has an average 20%reduction in the inter-story drift angle of each B-tower compared with the separately modeled B-tower.The displacements between the layers are approximately the same.The interlaminar shear force of the overall model of the A-tower under the action of the X-direction earthquake is generally smaller than that of the individual model,and the reduction value reaches more than 20%.While the overall modeling of the B tower is larger than that of the individual modeling,the growth accelerating rate of the connecting floors at the 3rd,6th and 7th floors respectively slowing down.The connection between the main towers and the connecting members enables the two main towers toto move coordinately have a coordinated movement.In terms of the deflection and comfort of the conjoined part,the deflection of the F3 bridge needs to be pre-arched 140mm to meet the specification requirements.The peak acceleration of F3 and F6 floor under the excitation of pedestrian load is greater than 0.07m/s2,which does not meet the comfort requirements of the office environment and requires the addition of TMD damping.(2)Using three different connection methods,rigidly connected,and elastically sliding bearings,the elastic sliding connection period is extended by about 60%compared with the free vibration period of the rigid joint and the articulated joint.The average floor maximum displacement of the elastic sliding connection is reduced by 0.5%compared with the fixed connection.Fixing connection is 1.5%less than articulation connection.The B tower has the greatest change in floor displacement under X-direction earthquake;The elastic sliding connection reduces the average displacement of the floor by 0.22%on average.The change trend of the shear-to-weight ratio increases as storey increases.Under earthquakes,the shear ratio of elastic sliding joints is larger than that of strong connections.The curve ofshear weight of the elastic sliding connection is smoother than the floor change curve.(3)When the damping of the viscoelastic damper reachest 5000 kN,the maximum displacement of the highest floor is minimized.However,when the stiffness value is changed to more than 2×10~6,then from this time on,the stiffness of the damper is mainly used for energy dissipation.The stiffness of the damping increases rapidly at 2×10~6,but as the stiffness continues to increase,the maximum interlayer displacement of the top layer changes slowly,and there is a tendency to decrease.The visco-elastic damper in the composite support is not very effective in reducing the seismic response of the structure.(4)Under the action of rare earthquakes,the X-side maximum displacement is 0.114m,the maximum interlayer displacement angle is 1/134,the Y-side maximum displacement is0.092m,and the maximum interlayer displacement angle is 1/144,all meeting the criterion.---1/100 requirement.Under the three-wave three-way effect,the degradation of the overall stiffness of the structure does not lead to the collapse of the structure,satisfying the fortification requirements of“don’t fall,in case of big earthquakes”.