Numerical investigation into thermal load responses of railway transom bridge

Abstract

Australian railway networks suffer a large fluctuation of extreme heats each year due to their wide variety of geographical conditions. Depending on climatic, cloud and radiation conditions, an ambient temperature of 20C could induce an equivalent thermal load absorption of track components as much as 30C to 35C or even more. As such, relatively high turnover of timber sleepers (crossties in a plain track), bearers (skeleton ties in a turnout), and transoms (bridge cross beams) can often be observed due to their unstable deformation and rapid deterioration. This paper investigates an application for the replacement of aging timber transoms mounted on existing railway bridges using fiber reinforced foamed urethane (FFU) transom beams, which are proven to provide environmental, safety and financial benefits. Clear benefits of the FFU material are the maintainability and constructability, especially for existing railway bridges. In this study, numerical simulations using finite element package ABAQUS have been carried out to illustrate the effect of thermal loads on the structural behavior of a railway transom bridge. The model was developed using a case study of an actual railway bridge in Kiama, Australia and it has been validated by field data measurements. It is found that nonlinear structural behavior of the bridge components exists at highly elevated temperatures. The better insight into the thermal load responses will lead to safer and more reliable rail stress adjustment practice, preventing rail misalignment or buckling.

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A three-dimensional method for the simulation of temperature fields induced by solar radiation

“…Thermal deformation and stress both have adverse effects on a structure’s serviceability and safety. Therefore, accurate determination of a structure’s temperature distribution has many applications in the design of prestressed concrete bridge girders (Barr et al, 2005), the assessment and selection of bridge expansion joints (Arockiasamy et al, 2008), the study of bridge performance using fiberglass-reinforced plastic and other new composite materials (Kong et al, 2014; Yu et al, 2008), the analysis of the thermal behavior of cracked concrete members in fire (Ervine et al, 2012; Wu et al, 2014), structural health monitoring of large bridges (Xia et al, 2013; Xu et al, 2010), and the study of track-bridge interactions in railway bridges (Mirza et al, 2015; Ryjáček and Vokáč, 2014) due to daily variations in temperature.…”