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Keywords: rail expansion joints, structural expansion joints, continuous welded rail, interaction track-structure.

Summary

For maintenance reasons in railway infrastructure, rail expansion joints must be avoided. The use of small isostatic suspensions was often used in the past design to lower the expansion length at the structural expansion joint. When using switches or turnouts on a viaduct, the sequence of small successive decks cannot be maintained. The contractor often requires the avoidance of structural expansion joints in switch and turnout zones and in a not negligible zone before and after the switches dependant on the type of switches. The P-switches can take full force without a need for rail expansion joints. Continuous suspensions in an integral bridge concept can give a solution when the deformation of the bridge arising from temperature loading is limited. This paper describes the possibilities and limits of this concept using a case study of a viaduct for a triple track system with switches and slab track. Although the current criteria in the UIC 774-3 for limiting the stresses in rails are consistent between the current rail codes and structural design codes; the application of it is less clear. For ballasted tracks the limits seem to be correct. Only the combination can be optimized. In the case of slab track the limits are too severe and can be raised significantly compared with ballasted track. By applying the UIC 774-3 code the slab track gets higher stresses due to the temperature loading (more rigid bridge-track interaction), but the limits remain low. The author suggests here much higher limits in favour of the slab track. The designer will be less penalized when using a slab track system. Also the same optimization for the combination of load cases can be used as for the ballast track. The third aspect is the determination of the temperature loading on the deck. The UIC 774-3 code uses 35°C instead of the real temperature loading for the region. These three aspects give some new instruments to the designer to optimize and mainly reduce the number of rail expansion joints at bridge expansion joints.

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Front Page Browse CCP CSETS CTR IJRT Other Authors Search Purchase Guide FAQ Contact us	Civil-Comp Proceedings ISSN 1759-3433 CCP: 98 PROCEEDINGS OF THE FIRST INTERNATIONAL CONFERENCE ON RAILWAY TECHNOLOGY: RESEARCH, DEVELOPMENT AND MAINTENANCE Edited by: J. Pombo Paper 6 An Integral Bridge Concept in Avoiding Railway Expansion Joints D. Decloedt¹, B. De Pauw^1,2 and Ph. Van Bogaert^1,2 ¹Tuc Rail Ltd., Railway Design Office, Brussels, Belgium ²Civil Engineering Department, Ghent University, Belgium doi:10.4203/ccp.98.6 purchase the full-text of this paper Full Bibliographic Reference for this paper D. Decloedt, B. De Pauw, Ph. Van Bogaert, "An Integral Bridge Concept in Avoiding Railway Expansion Joints", in J. Pombo, (Editor), "Proceedings of the First International Conference on Railway Technology: Research, Development and Maintenance", Civil-Comp Press, Stirlingshire, UK, Paper 6, 2012. doi:10.4203/ccp.98.6 Keywords: rail expansion joints, structural expansion joints, continuous welded rail, interaction track-structure. Summary For maintenance reasons in railway infrastructure, rail expansion joints must be avoided. The use of small isostatic suspensions was often used in the past design to lower the expansion length at the structural expansion joint. When using switches or turnouts on a viaduct, the sequence of small successive decks cannot be maintained. The contractor often requires the avoidance of structural expansion joints in switch and turnout zones and in a not negligible zone before and after the switches dependant on the type of switches. The P-switches can take full force without a need for rail expansion joints. Continuous suspensions in an integral bridge concept can give a solution when the deformation of the bridge arising from temperature loading is limited. This paper describes the possibilities and limits of this concept using a case study of a viaduct for a triple track system with switches and slab track. Although the current criteria in the UIC 774-3 for limiting the stresses in rails are consistent between the current rail codes and structural design codes; the application of it is less clear. For ballasted tracks the limits seem to be correct. Only the combination can be optimized. In the case of slab track the limits are too severe and can be raised significantly compared with ballasted track. By applying the UIC 774-3 code the slab track gets higher stresses due to the temperature loading (more rigid bridge-track interaction), but the limits remain low. The author suggests here much higher limits in favour of the slab track. The designer will be less penalized when using a slab track system. Also the same optimization for the combination of load cases can be used as for the ballast track. The third aspect is the determination of the temperature loading on the deck. The UIC 774-3 code uses 35°C instead of the real temperature loading for the region. These three aspects give some new instruments to the designer to optimize and mainly reduce the number of rail expansion joints at bridge expansion joints. purchase the full-text of this paper (price £20) go to the previous paper go to the next paper return to the table of contents return to the book description purchase this book (price £110 +P&P)
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