| The history of the development of ordinary concrete filled steel tubular arch bridge at home and abroad have been long,and wide range of applications,in the bridge construction has played an important role,which can not be replaced in recent years,China has introduced a system of Nelson tied arch bridge,the main feature of this kind of arch bridge with inclined hangers instead of the traditional vertical sling,the arch bridge will drive the new development,but with the increase of the span of the bridge deck,wider,transverse mechanical problems and beam characteristics of the arch bridge stability problems have become increasingly prominent,there is very little research on the stability of the Nelson system of arch rib tied arch bridge,the transverse mechanical characteristics analysis of Nelson system tied beams there is more uncertainty.In this paper,the stability of Nelson tied arch bridge and the lateral mechanical characteristics of beam system are deeply studied,and the relevant conclusions can be drawn,which can provide a powerful reference for engineering construction.First of all,this paper refers to a large number of domestic and international literature about bridge,introduces the history and current research situation of the tied arch bridge of Nielsen system both at home and abroad,and the significance of this topic and the main research work.At home and abroad has yet to see the unified rules and regulations(the design and construction of CFST arch bridge),this led to the current design and construction at home and abroad are quite free,it is difficult to strictly control its rationality,and Nelson tied the system of arch bridge is a new type of tied arch structure.It is not the design and construction of a unified standard,in this case,the blind with previous experience of arch bridge design and construction,the project may lead to disease or even collapse accidents such as unreasonable design and construction of the blind.Therefore,the research on the static and dynamic performance of CFST arch bridge of Nelson tied arch bridge is urgently needed,so as to provide a reliable theoretical basis for its reasonable design and construction.As a global power infrastructure,there has been a lot of ordinary concrete filled steel tube arch bridge experience in China,for the tied arch bridge has laid an important foundation in China’s rapid development,but the experience of Nelson tied arch bridge system is less and less,foreign countries have to have rich application and development,and research mature,by contrast,domestic scholars even on ordinary concrete filled steel tube arch bridge is just unfolding,and Study on the system of Nelson tied arch bridge of CFST arch bridge has not been carried out.Secondly,we study the theory of stability.In the design of arch bridges,the problem of instability can not be ignored,so it is of great significance to study the instability of arch.A detailed study on face stability problem from the theoretical level of instability,including theapproximate solution of the finite element method first stability problem analysis and the nonlinear state,and the first instability and instability in the in-plane buckling theory and finite element solution method.On the basis of theoretical analysis,this paper combined with practical engineering,the stability factors on the arch rib tied arch bridge system and influence of Nelson,a member structure finite element model using the finite element software MIDAS,influence the comparative analysis of 4 kinds of loading conditions,5 kinds of cross brace form,change of transverse brace stiffness and change the prestressed arch rib on stability,and draws a conclusion: in the study of load on the arch rib stability influence can be seen in the lateral wind load of arch rib has little effect and stability,beam on vertical load increasing,the stability of arch rib is significantly reduced,it can be seen that deliver more load to the arch rib in the sling.The stability decreased;the transverse brace between the arch form has obvious influence on the stability of the arch rib,a comparative analysis can be seen on both sides of the two meter intermediate support group K brace brace form is that the economy Brace form and effective;cross brace stiffness of arch rib structure also makes the overall stability increased,but with the bracing stiffness of arch rib and further improve the overall stability of the limited,and both sides cross brace stiffness changes have great influence on the structure stability coefficient,finite element analysis based on the results,suggestions of midgastric transverse the support stiffness is reduced to 0.6 times of the original design,the edge bracing remains unchanged,so the overall stability decreased only1.16%,in almost does not reduce the structural stability become more economical;and the increase of the applied prestressed arch rib stability coefficient increased,from the analysis of quantity increase,prestressed load the base increased from 0.2 to 1.8,the stability coefficient increased from 12.10 to 12.54,an increase of 3.64%,visible on arch rib stability of prestressed effect.Thirdly,the method of transverse internal force analysis of box girder bridge is discussed,and the main methods of lateral analysis of box girder,such as plane frame method,plate element method and influence surface method,are discussed.The basic theory based on combining the actual project: Zheng Wan 128 M Nelson system tied arch bridge,stone river bridge,the bridge section of the chamber and the beam of the fine finite element analysis program,established finite element model for the whole bridge,plane frame system of beam section,cross section of the beam,the beam plate element beam model,beam and plate element model established by ANSYS simplified segment finite element model,the beam transverse mechanical properties compared with the solid model of the whole bridge analysis system of arch bridge,Nelson.Analysis of the plane frame method can only be applied to the chamber without diaphragm or diaphragm vertical distance big box girder,the diaphragm box girder using plate element calculation is more accurate and convenient operation etc.the mainconclusions.It is considered that there is a peak point of stress in the side web,the side room,the midspan,the middle web and the middle span,and the design value should be the most unfavorable point... |
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