| With the rapid development of the world economy and the rapid changes in infrastructure construction,the development of cable-stayed bridges and continuous girder bridges as traditional bridges has become more and more mature.However,with the increasing demand for various convenient ways,engineers have to face various kinds of complex terrain,and the traditional bridge structure may no longer be able to meet the economic convenience,safety and aesthetic design needs,etc.Combining two or more technically mature bridge structures together,so that their structures can collaborate with each other to complement each other’s strengths and weaknesses,is also an innovative method.Compared with traditional cable-stayed bridges,the collaborative system,which consists of a cable-stayed bridge and a continuous girder bridge,has the advantages of more flexible structure,stronger spanning capacity,more beautiful structure,and better adaptability to complex terrain,etc.Therefore,it is favored by more and more engineers.As an innovative bridge system,it is necessary to analyze the structural characteristics of the collaborative system.The article takes a traditional asymmetric single-tower cable-stayed bridge as the background,by changing the connection method of the cable-stayed bridge and the girder bridge,so that the main girders of the cable-stayed bridge and the girder bridge are partially rigidly connected,i.e.,the main girders are continuous,constituting a cable-stayedcontinuous collaborative system,and the finite element model is established by using SAP2000 finite element software to analyze the static and dynamic characteristics of the cable-stayed-continuous collaborative system,as follows.（1）By studying the load distribution problem of the collaborative system,a systematic classification of the collaborative system is carried out,and a simplified analysis of the collaborative system is carried out through the theory.The theoretical study shows that the diagonal-tension-continuous collaborative system,the object of the article,belongs to the type of load distribution collaboration,and the stiffness of the collaborative system with continuous main beams is stronger than that of the original structure,which makes the structure more stable and fully brings out the advantages of each basic system.（2）The finite element calculation model of the bridge is proposed by SAP2000 finite element software,and the static analysis is compared with that of the conventional cable-stayed bridge,and the main girder bending moment,axial force and deflection characteristics of the two bridge types under the same constant load,live load,temperature load and load combination are studied.The results show that under the same load,compared with the conventional cable-stayed bridge,the overall stiffness of the cable-stayed-continuous collaborative system is greater,and the internal forces of the main girders are more uniformly distributed,and the influence of constant load and live load on the structure can be effectively reduced,and the structure can better adapt to temperature changes,but also increases the negative bending moment borne by some piers.（3）The self-vibration characteristics of the diagonal-continuous collaborative system are calculated and analyzed,and the self-vibration periods and frequencies of the first 10 orders of the bridge are calculated and the self-vibration characteristics of the first 10 orders are summarized.The study shows that the self-oscillation frequency of the tenth-order vibration type of the structure is increased by 425% compared with that of the first-order vibration type,which indicates that the fundamental frequency of this type of diagonal-continuous collaborative system bridge is relatively small and the frequency spectrum is more dispersed.The lower order vibration pattern of the structure contributes more to the calculation results.The first and second order vibration patterns of the structure show transverse bending of the main tower,and the third order vibration pattern shows vertical bending of the main beam and longitudinal bending of the tower,which indicates that the transverse stiffness of the bridge is relatively small,and the longitudinal stiffness and vertical stiffness are relatively large,so the seismic design should focus on controlling the transverse displacement of the main tower.（4）Based on the analysis theory of dynamic characteristics,the response spectra of the diagonal-continuous collaborative system were analyzed under E1 and E2 earthquakes,and the seismic response of the structure was calculated in the cis-bridge direction,cross-bridge direction,vertical direction and three-way earthquake,and the general rule of the seismic response of the bridge was obtained.The study shows that the transverse displacement of the main section displacement is the largest and the vertical displacement is the smallest,which indicates that the bridge has the smallest transverse stiffness and the largest vertical stiffness,which is consistent with the conclusion of the self-oscillation characteristics analysis,therefore,in the seismic design,it is necessary to focus on controlling the transverse displacement of the bridge;the internal force response of the control section of the main girder and the main pier4# pier is the most obvious,therefore,in the seismic design,it is necessary to focus on controlling the internal force of the control section of the main girder and the Therefore,in the seismic design,the internal force of the control section of the main girder and the bottom section of the main pier 4# pier should be considered.（5）The time course analysis was carried out for the diagonal-continuous collaborative system bridge,and three seismic waves suitable for the characteristics of the project site were selected,and the maximum value of the three sets of seismic wave calculation results was taken as the calculation results of the time course analysis,and the results obtained were compared with the results of the reaction spectrum calculation under the E1 earthquake.The study shows that the overall difference between the results of the reaction spectrum and the results of the time course method is not large and within the allowable range,but only in the individual displacement response and internal force response of individual cross-section is obvious.（6）Under the action of nonlinear earthquakes,three seismic waves appear in the top and bottom sections of some piers into the yielding phase,but not into the damage phase,all within the safe use,and the displacement of the top of the piers and the plastic angle are within the allowed range and in line with the seismic performance index of the structure under the action of strong earthquakes.Figure [60] Table [54] reference [60]... |
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