Dynamic Behavior Study On Long-span Steel Deck Girder Pavement System

The long-span steel bridge is becoming the main direction of development of bridges in our country.Steel deck pavement system is not only an important part of steel bridge,but also one of the key technologies and difficulties in the construction of long-span steel bridge.According to the structural characteristics of steel deck pavement system,the dynamic characteristics of steel deck pavement system are systematically studied based on theoretical derivation and numerical analysis in this paper.The main contents of this paper are as follows:(1)This paper shows a more exact and practical finite element model of the steel girder deck pavement.Based on Mindlin thick plate theory,a 12-node solid thick plate element is constituted to analyze the pavement.The computation result is compared with that by traditional 4-node and 8-node thick plate finite element,and is satisfactory.A combined plate beam element method is presented to investigate the stiffened plate.A 6-node solid thin plate element is constituted to analyze the top plate based on Kirchhoff thin plate theory.The stiffeners playing the vertical supporting function mainly are taken as Euler beam elements.A method of using the linear interpolation to realize the longitudinal displacement and the cubic Hermite interpolation to the vertical displacement is presented to analyze the stiffeners.In addition,it is essential to consider the displacement coordination between the top plate and stiffeners.A node-to-node contact scheme,which is applicable for three-dimensional contact analyses involving large deformations,is used to treat the contact problem between pavement and stiffened plate by Lagrange multiplier methods.(2)The steel deck pavement system is divided into three parts: pavement,top plate and stiffeners of stiffened plate.The strain energy and kinetic energy of them are given based on the principle of energy.Then,the nonlinear vibration equation of steel deck pavement system is deduced through the use of Lagrange equation.(3)Single-modal method is presented to investigate the nonlinear vibration of steel deck pavement systems with four edges simply supported and four edges clamped.The second approximation solutions of free vibration and forced vibration of the system are obtained by means of the method of multiple scales.Numerical examples for steel deck pavement systems are presented to discuss the impact of the relation between amplitude and nonlinear frequency ratio on the arrangement of stiffeners,elastic modulus and thickness of pavement of free vibration.And discuss the impact of the steady-state response of the non-resonance and the amplitude-frequency response of the primary resonance on the arrangement of stiffeners,elastic modulus and thickness of pavement of forced vibration.In addition,discuss the impact of nonlinear vibration of the whole steel deck pavement system on material damping.(4)The pavement of steel deck pavement system is considered as viscoelastic body.Single-modal method is presented to investigate the impact of nonlinear vibration of steel deck viscoelastic pavement system with four edges simply supported and four edges clamped on the viscosity coefficient of pavement.The second approximation solutions of free vibration and primary vibration of the system are obtained by means of the method of multiple scales.Numerical examples for steel deck pavement systems are presented to discuss the impact of the variation of nonlinear frequency ratio,amplitude and the relationship between them with time on the viscosity coefficient of pavement of free vibration.And discuss the impact of the amplitude-frequency response of the primary resonance on the viscosity coefficient of pavement.