Study On Nonlinear Static And Dynamic Analysis And Emulation Of Additional Longitudinal Forces In Railway Bridges

On account of the situation of the train speed rising all over the country and the urgentdemand for development of high-speed railway,the static and dynamic interaction betweencontinuous welded rail and multi-span or long span bridge are studied systematically in this thesis.The principle of interaction between rail and bridge has been reasoned, the mechanism of theformation of longitudinal additional forces including braking force, bending force and temperatureforce and also solution method are profoundly deduced, the comparison between the traditionaldifferential method and the modern numerical method has been conducted. In order to analyzingnonlinear static and dynamic interaction between tail and bridge thoroughly,the author pay muchattention to the study of numerical solution method such as tangent stiffness method,increasingmethod with small step, increasing method with automatically chosen changing step for solvingnonlinear equation, fast solution method of linear equations, shrinkage method of freedom,different step by step integration method, the eigenvalue calculation using both sift matrix andinverse reiteration,etc, and make full use of these different arithmetic technology synthetically todevelop a set of programs,which are suitable for nonlinear static and dynamic analysis oflongitudinal additional forces in large-scale bridge structures with large lnumber degree offreedom. The same results from different methods and its consistence with the tested data fromfield measurement confirmed the correctness of the programs. Applying the programs to theparametric analysis, the influence on longitudinal forces of longitudinal resistance, span number,substructure stiffness, bearing type etc. and on longitudinal forces the longitudinal forces'transmission performance,especially the relation between the effective braking force rate and thetail above braking force rate in common used multi-span simply supported girders,have beenresearched. With the rail reconstruction of the Hongshui River Bridge its longitudinalperformance and the reasonable arrangement of rail expansion joint has been studied. Based onthe principle of vehicle braking procedure, the longitudinal balance equations are set up, and theaccording spectra of braking forces subject to braking time and train position, and the rail abovebraking force rate of common used freight train have been obtained. By inputting the brakingforces obtained to the model of Wuhu Yangtze River Bridge, the nonlinear dynamic responses tothe longitudinal forces under different factors of original train velocity stopping position, railStrUCtUre,damping of longitUdinal edctions etc., are ~ied profoundly and thoroedly and theimportan concIusions which can be referable tO the design of this type of bridges haV beendrawn Ou. Finally by combining the finite elemen method and the visual PrOpeminglanguage, the aUthor develoPPed a emulation software with friendly iuput and outputinterfaCe,which have been used firStty to the emulation of longitudinal fOrces in case ofmoving load on bridge, nd aiso the simultanious animaton Of the bening diSPlacemnt of thebridge hav been conducted.,...