Keywords: Fondation ; Mur de soutenement ; Pieux ; Capacite portante ; Ancrage ; Dimensionnement Reference Record created on 2004-09-07, modified on 2016-08-08

Tubular Modular Track (TMT) is a relatively new rail design invented in 1989. The system is ballastless and is designed to continuously support the rails on twin reinforced concrete (RC) beams which are founded on a specially designed subgrade. These RC beams are linked together by galvanised steel gauge bars which encircle the RC beams and provide links to fasten the rails to the RC beams with the use of rail clip fasteners. Elastomeric pads are placed in-between the rail and the RC beam to provide shock and sound absorption and grout is placed below the RC beams to level the TMT beams and ensure constant contact between the RC beams and the subgrade. With the introduction of high speed trains and ballastless rail systems the design of the transitions between ballasted and ballastless rails needs special attention. Multiple studies have been done on transitions between various types of ballastless rail and ballasted rail, but limited research is available on transitions between TMT and ballasted rail. To improve the confidence in the use of the TMT system in a transition various analyses are performed on the RC beam, the main supporting component of the system, for varying train speeds and varying rail irregularity angles due to elevation changes in the rail which occur because of ballast settlement at the track transition. The TMT structure is supported by different layers of subgrade which need to be incorporated in the finite element (FE) model of the system, but modelling the subgrade as a continuum increases the computational cost of the analysis. To simplify the modelling of the subgrade elastic foundation theory with plate bearing test (PBT) models are investigated. The subgrade can then be replaced with an elastic support. The PBT model and the elastic subgrade stiffness are verified by using previous research models which simulate PBT and determine an elastic stiffness to replace the subgrade. To analyse the TMT structural components a static, three-dimensional (3D), FE model is created of the structure. The TMT 3D model is also verified using models used in previous research which analysed the TMT structure. A 3D model of the structure requires a fine mesh to accurately model the cross sections of the TMT components, making the analysis computationally expensive. To simplify the model a two-dimensional (2D) model is created using beam and plane stress elements. For the 2D model a damping factor sensitivity analysis is performed to determine the influence of damping on the behaviour of the structure. The 2D model is then loaded statically and dynamically to determine the dynamic amplification factor (DAF) for the displacements, bending moments and shear forces in the rail and RC beam. ii Stellenbosch University https://scholar.sun.ac.za

background or methods

Foundation analysis and design

Analysis of the transition between Tubular Modular Track and ballasted railway

/pdf/design-construction-and-performance-of-a-deep-braced-255zrq0t19.pdf

Design, Construction, and Performance of a Deep Braced Excavation

Swell Pressures and Retaining Wall Design in Expansıve Soils

/pdf/an-investigation-of-load-and-resistance-factor-design-of-1uiqlcub5d.pdf

An Investigation of Load and Resistance Factor Design of Drilled Shafts Using Historical Field Test Data

The aim of the present paper is to evaluate the influence of the Soil- Foundation- Structure Interaction (SFSI) effects on the component demand modifier factor of concrete gravity beams based on ASCE 41-06 standard. To this end, the beam on the nonlinear Winkler foundation approach is employed which is a simple and efficient method. At first, four sets of 3-, 6-, 10- and 15-storey concrete momentresisting frames founded on soft, medium and hard soils are designed and analysed for the case of fixed-base and flexible-base assumptions. A comparison is then made between the results of the nonlinear response history analysis of each frame in the flexible-base and fixed-base conditions with the response based on the equivalent linear static approach. The findings show that the equivalent linear static approach loads for gravity beams, which are controlled by deformation actions, can lead to non-conservative predictions of seismic demand. Finally, a modified load combination is proposed to be used in the equivalent linear static approach to avoid this imperfection. Key word: CE Database subject headings; Winkler spring; Soil-Foundation-Structure Interaction; ASCE 41-06 standard; Nonlinear seismic response history analysis; Ground motion.

http://www.qjseg.ir/article_728_ea37df92e22b6793f4608d63faf12770.pdf

Foundation analysis and design

Citations

Analysis of the transition between Tubular Modular Track and ballasted railway

Design, Construction, and Performance of a Deep Braced Excavation

Swell Pressures and Retaining Wall Design in Expansıve Soils

An Investigation of Load and Resistance Factor Design of Drilled Shafts Using Historical Field Test Data

Effects of the Soil-Foundation-Structure Interaction on the Component Demand Modifier Factor of Concrete Gravity Beams based on ASCE 41-06 Standard

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