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Study On Dynamic Response Of Structures And Ground Subjected To Moving Loads

Posted on:2006-09-05Degree:DoctorType:Dissertation
Country:ChinaCandidate:H F ZhouFull Text:PDF
GTID:1102360152993474Subject:Civil engineering
Abstract/Summary:PDF Full Text Request
To study the traffic induced structure borne and ground borne vibrations, four types of structures and ground were formulated to model the railway track and highway or runway pavement system, including (i) infinite beam on Kelvin foundation, (ii) infinite beam on an elastic half-space, (iii) infinite plate on Kelvin foundation, and (iv) a visco-elastic half-space. The first two can be used to model the railway track, the third one model the highway or runway pavement system, and the last model the ground.Moving loads were utilized to model the wheel loads and could be classified into various groups according to their spatial distribution function and temporal variation function. In terms of spatial distribution, mainly three kinds of moving loads were considered, i.e., (i) moving point source, (ii) moving line source, and (iii) moving area source. In terms of temporal variation, two kinds of moving loads were considered, including (i) constant load, and (ii) harmonic load. Besides the single wheel loads, multiple wheel loads were also studied. A seires of moving point load was utilized to model the axle loads acted on the railway track by trains, an array of moving load, each unfiromly distributed over a rectangular area, model the axle loads acted on the highway pavement system by tandem double wheel trucks, and a seires of elastically distribured moving load model loads acted on the gournd by the railway track under multiple axle loads.Two kinds of dynamic response, i.e., transient response and steady-state response, were studied for each of the four models, respectively. For transient response, focuses were mainly placed on simulating the whole process in which transient response evolve into steady-state response and the impact effects induced by suddenly applied moving loads. For steady-state response, however, focuses were mainly placed on investigating the effect of various parameters on the steady-state response.Analytical solutions of the dynamic responses were developed by two methods, i.e., Green's function method and integral transform method. For Green's function method, generalized Duhamel's integral, which is eurytopic to solve dynamic responses of linear system were presented first. Green's function for each model was then developed in the transformed field using Fourier transform and/or Laplace transform. Dynamic responses were finally expressed as convolution integrals between moving loads and Green's function. Green's function method is applicable to solve all the four models, however, it's not the...
Keywords/Search Tags:environmental vibration, traffic loading, moving load, Kelvin foundation, infinite beam, infinite plate, visco-elastic half-space, Green's function, Duhamel's integral, transient response, steay-state response
PDF Full Text Request
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