Seismic Responses Analysis Of Self-anchored Cable-stayed Suspension Bridge

As a new type of structural system that is used to super largest span bridge, self-anchored cable-stayed suspension bridge has both merits of self-anchored suspension bridge and cable-stayed bridge,which has vast foreground in applications. From the document that has existed, there is little research of dynamic behavior for self-anchored cable-stayed suspension bridge.Combined with the engineering practice that is a self-anchored cable-stayed suspension bridge located in Dalian bay with the main span is 800m (hereinafter referred as Dalian Bay Bridge), and based on the informations published in literatures available ,the dynamic behavior and seismic response of self-anchored cable-stayed suspension bridge are analysised in this paper. The main research work covers the following aspects:(1) Based on the space finite element Principle,the bridge model with refered to Dalian Bay Bridge for seismic analysis is established,and the the first 10 frequencies and corresponding vibration modes are given . At the same time, effects caused by varieties of the assistant piers numbers , bound manner in foundation and restriction format of grider are computed. The results are compared with those of an earth-anchored suspension bridge and a cable-stayed bridge with the same and structure parameter.The influence regulations are discussed in detail..(2 ) Following the fortifying demand of three-level seismic resistance, under the effect of earthquake probability PI, the seismic response of Dalian Bay Bridge is analyzed by the Response Spectrum Method.under vertical, longitudinal, and lateral seismic excitation and two kinds of seismic combinational modes which are longitudinal vibration plus vertical vibration and transverse plus vertical seismic excitation.Besiders, influence to the seismic response because of changes in the manner of the assistant piers and differents in the bound manner of foundation and restriction forms of grider are disscused, the results of an earth-anchored suspension bridge and a cable-stayed bridge with the same and structure parameter are compared . In order to ensure the precision, the CQC(Complete Quadratic Combination)approach is applied. The method and conclusion can conduct the preliminary design of similar bridge.(3) In the condition of multiple-support linear uniform, nonlinear uniform and traveling wave effect excitation, the response time histories of internal force and displacementof controlling section such as main beam, tower are analyzed and compared. The effect regulation is discussed in detail.(4) The spectral analysis is linear so the nonlinear factors can be taken into account,however, The dynamic time-history analysis is able to consider some nonlinear factors. Iin this papers, the earthquake response results of Dalian Bay Bridge are carried out with detailed correlation and verification which used the three seismic analysis methods:: multiple-support nonlinear uniform dynamic time-history analysis and traveling wave effect excitation time-history dynamic analysis and the spectral analysis. Such type of bridge earthquake analysis suitable methods are won.