Research On The Stability, Static And Dynamic Characteristics Of Long-span Steel Truss Arch Bridge And Scheme Comparison

This Paper ma inly a nalys is the stability, static a nd dyna mic c haracteristic ofMengDong River Brid ge, a deck steel truss brid ge with a span of450m. Two differe ntdesign sche mes are put forward in this Paper and the pros and cons of the m arecompared. This Paper will provide practica l reference for the design of s imilarbridges.Firstly, this Paper provides the basic information o f several well-known steeltruss arch bridges both in domestic and foreign countries, such as the history, ordinarydesign of the structura l system, category and its rela tive merits. The current researchabout the stability and response to static force is provided in this Paper. Moreover, theconcept of the stability, critica l criterion of instab ility and the form of the instab ilityare also introduced.Secondly, the finite eleme nt mode l of the MengDong River Bridge based on thefirst design is built with MIDAS. Static response to the dead, mo ving and temperatureload is calculated respective ly. The steel truss arch bridge is divided into eight Parts:arch rib chord, web me mber, bracing, interior le g brace, stand column and theconnectio n between them, s ide pier and the cross-brace between the m, bend cap andgirder. The static response of each Part is calculated and the distribution Pattern ofwhich is disc ussed based on the results. The static capacity is checked under threedifferent load comb ination conditio ns.Third ly, finite ele ment model of MengDo ng River Brid ge based on the firstdesign is built with ANSYS. The dyna mic characteristics of the naked arch andcomp leted bridge a nd the e lastic stab ility coeffic ie nt of the comp leted bridge areanalyzed. The elastic stability coeffic ie nt and nonlinear stability coeffic ie nt of thenaked arch are utilized to find out the influe nces of geo metric no nlinearity on thestability o f the stee l truss arch. The stab ility o f the finite models with vary number ofele ments is analyzed respective ly and compared.Fina lly, the second scheme of MengDo ng River Bridge is designed based on thedesign characteristics of the New River Gorge Bridge. In order to obta in an effectivemethod assuring the approximate stability coeffic ie nt of the arch rib, the influence ofdifferent section dime ns ion o f several components inc luded arch rib chord, webme mber and bracing on the stability is studied. Cons idering the economic factor and structura l response, the later is superior to the former. Moreover, the construction o fthe second sche me is much more convenie nt because of the relative fewer number ofthe ele ments.