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Ge J.,Shanghai Institute of Technology | Shen L.,Shanghai Institute of Technology | Wang Z.,Tongji University | Yan P.,China Construction Shenzhen Design International
Wuhan Ligong Daxue Xuebao (Jiaotong Kexue Yu Gongcheng Ban)/Journal of Wuhan University of Technology (Transportation Science and Engineering) | Year: 2013

Based on model test of high-speed railway girder under repeated loading, the relationship between nonlinear and dynamic characteristic using planar nonlinear finite element method has been studied. The elastic-plastic behavior of concrete is defined by the equivalent stress and equivalent plastic strain. After the numerical model is unloaded from different load levels, the mode analysis is performed, that is the vibration frequency and mode shape is calculated after unloading. The results show that the non-linear characteristic of box girder can be modeled accurately using the planar nonlinear finite element analysis method. The characteristic values of skeleton curve, loading and unloading stiffness and the residual displacement from finite element method are in good agreement with that from experiment, except model error in the initial stiffness. The modal analysis based on static nonlinear analysis is practicable. The value changes of vertical frequency can reflect the occurrence of static nonlinear structural damage and the law of damage development. That is an effective way to damage identification from dynamic characteristics of structural. Source

Zhang Z.-H.,China Construction Shenzhen Design International | Dong S.-L.,Zhejiang University
International Journal of Space Structures | Year: 2010

A novel spatial cable-frame type of suspended single-layer reticulated shells with free surface (Spatial cable frame plus single-layer reticulated shell with free surface) is proposed in the present paper. Shape determination problem of the lower cable-bar system of general hybrid spatial structures with free surface upper structure is also put forward and investigated. Shape determination problem in essence is one kind of calculus of variation problem. On the basis of the general inverse of equilibrium matrix of the lower cable-bar system and dynamic relaxation method an efficient numerical algorithm is also given out in details. This numerical algorithm is programmed by using VC++ 6.0 and is also validated by numerical examples. Hopefully the work in the present paper could benefit the further research work and practical engineering on general hybrid spatial structures. Source

Cao Q.-s.,Huasen Architectural and Engineering Design Consultants Ltd. | Zhang Z.-h.,China Construction Shenzhen Design International
Engineering Structures | Year: 2010

The suspendome has been widely used as the structural roof system of sports buildings in recent years. It is a kind of hybrid space structure composed of an upper rigid single-layer latticed shell and a lower flexible tensegrity (cable-strut) system. The prestress level in the lower cable-strut system is of great significance for the suspendome structure because it has no initial geometric stiffness (for a rib-ring type) before prestress is introduced into the lower tensegrity system. The traditional solution for calculating the self-internal-force mode and the prestress force level (force finding) is somewhat complicated; in general it is based on the Equilibrium Matrix Theory. In the present paper, a simplified computational strategy for the determination of the self-internal-force mode based on the nodal equilibrium is presented for the tensegrity system in a suspendome which is grounded on a newly developed method: the Local Analysis Method. Two types of cable-strut arrangement, the Levy system and the Geiger system, are addressed, and the characteristic of each type is expounded. An analytical solution for the self-internal-force mode of the lower cable-strut system is put forward together with the equivalent nodal force acting on the upper single-layer dome for the two types of cable-strut arrangement. The determination of the prestress level of the lower tensegrity system is then elucidated on the ground of the initial architectural configuration, the counterbalance of the bearing reaction, the equivalent nodal force, and the wind-induced slackening effect. An illustrative example is appended in the end to validate the efficiency of this simplified method. It is shown that force finding, at the viewpoint of structural design, based on this method is of great accuracy and efficiency. The prestress in the outermost ring generally has the highest level among the cable-strut system, and has the most influence on the structural performance of the suspendome. The results from the studies can be referred to not only for direct design use in practical engineering, but also for the design of similar hybrid space structures. © 2009 Elsevier Ltd. All rights reserved. Source

Chen M.,Central South University of forestry and Technology | He G.,Central South University of forestry and Technology | Liu C.,China Construction Shenzhen Design International
Applied Mechanics and Materials | Year: 2012

Energy dissipation structure is favored by designers because the earthquake energy can be dissipated by the dampers, which can avoid or reduce the damage caused by earthquake. However, the energy dissipation structure design is complex and the most domestic designers can not master it easily. In this paper, a simple and practicable design method for viscous damper dissipation structure by using the PKPM design software is proposed based on a 7-storey frame structure in highly seismic region. Firstly, lower half or one degree for the design intensity to design out an uncontrolled structure. Secondly, determine the supplemental damping ratio required for the fortification intensity via modal analysis method of PKPM software, and identify the numbers of the required dampers as well as their corresponding installation positions in line with the methods in the seismic code of China. Finally, the ETABS program is adopted to conduct the time-history analysis of the designed dissipation structure, showing that the proposed method in this paper can produce a satisfied result. © (2012) Trans Tech Publications, Switzerland. Source

Li Z.-q.,Tongji University | Zhang Z.-h.,Shanghai Normal University | Dong S.-l.,Zhejiang University | Fu X.-y.,China Construction Shenzhen Design International
Advanced Steel Construction | Year: 2012

Construction sequence simulation analysis of a practical suspen-dome of Jinan Olympic Center is discussed in the present paper. Suspen-dome is a kind of advanced large-span space structure which is composed of an upper single-layer latticed shell and a lower cable-bar system. It is also a kind of hybrid system due to a combination of cable elements, bar elements and beam elements. Construction errors and temperature fluctuation are of importance and need to be taken into consideration during the construction process. The construction error of the structure is simulated by using the random imperfection modal method. Using the integral structure model including the concrete supporting system, the effect of the temperature variation on the suspen-dome is analyzed. The construction of suspen-dome is a little complex due to the interaction between the upper single-layer latticed shell and the lower cable-bar system. The configurations of the structure during the construction could be determined by an inverse analysis method or a mixed analysis method depending on the stages adopted in each construction scheme. And the influence to the lower cable-bar system caused by the setting-up errors at nodes is studied on the basis of one feasible construction scheme. Some meaningful and universal conclusions are given out. Source

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