THE EFFECTS OF THE USE OF ELASTIC PADS ON DYNAMIC IMPACT FORCES IN RAILWAY TRACKS

Yıl 2022, Cilt: 2 Sayı: 2, 140 - 151, 21.06.2022

Erdem Balcı , Niyazi Özgür Bezgin

Öz

Conventional railway tracks consist of rail, pad, sleeper, ballast, and sub-ballast layers. Equivalent track stiffness is the combination of the stiffness of these layers. The stiffness of the elastic pads affects the equivalent track stiffness and thus, track performance. Especially in critical areas where an earth-supported track is passed to a concrete-supported track or from a concrete-supported track to an earth-supported track, the stiffness differences between the two regions may cause high dynamic impact force values. A “transition zone” should be designed using elastic pads in these areas.

Bezgin Method relates the equivalent track and system stiffness with the dynamic impact forces. In this work, the effects of the use of elastic pads on the dynamic impact forces are analytically investigated by using Bezgin Method. It is seen that dynamic impact forces that occur while a train passes over the zones with different stiffness values can be reduced up to %27. Required works to understand the effects of rail pads and under sleeper pads on the track performance are suggested.

Anahtar Kelimeler

Rail Pad, Under Sleeper Pad, Track Stiffness, Dynamic Impact Forces, Bezgin Method

DEMİRYOLU HATLARINDA ELASTİK PED KULLANIMININ DİNAMİK DARBE KUVVETLERİ ÜZERİNDEKİ ETKİSİ

Öz

Geleneksel demiryolları ray, ped, travers, balast ve altbalast katmanlarından meydana gelmektedir. Demiryolu hattına ait eşdeğer esneme direnci ise bu bileşenlerin esneme dirençlerinin bir kombinasyonudur. Elastik pedlerin esneme direnci, hattın esneme direncini etkileyerek hat performansı üzerinde önemli bir rol oynar. Özellikle toprak destekli bir hattan beton destekli bir hatta veya beton destekli bir hattan toprak destekli bir hatta geçilen kritik bölgelerde, iki bölge arasındaki esneme direnci farkları yüksek dinamik darbe kuvveti değerlerinin oluşmasına neden olabilmektedir. Bu bölgelerde elastik pedler kullanılarak bir “geçiş bölgesi” tasarlanmalıdır.

Bezgin Yöntemi, eşdeğer hat ve sistem esneme dirençleri ile dinamik darbe kuvvetlerini ilişkilendirir. Bu çalışmada, elastik ped kullanımının demiryolu hattına aktarılan dinamik kuvvetler üzerindeki etkisi Bezgin Yöntemi kullanılarak analitik olarak incelenmiştir. Farklı esneme direnç değerlerine sahip bölgeler arasında geçiş yapılırken ortaya çıkan dinamik kuvvetlerin, elastik ped kullanımıyla %27’ye kadar azaltılabileceği görülmüştür. Ray pedleri ve travers altı pedlerin hat performansına etkisinin daha iyi anlaşılabilmesi için yapılması gereken çalışmalar hakkında öneriler sunulmuştur.

Anahtar Kelimeler

Ray pedi, Travers Altı Pedi, Hat Esneme Direnci, Dinamik Darbe Kuvvetleri, Bezgin Yöntemi

Kaynakça

• Balcı, E., 2021. Ray Pedi ve Travers Altı Pedlerin Hat Bileşenleri ve Hat Performansı Üzerindeki Etkileri. Demiryolu Mühendisliği, 13, 14-28.
• Balcı, E., Bezgin, N. Ö., 2020. Hat Esneme Direncinin Hat Performansı Üzerindeki Etkileri. Demiryolu Mühendisliği, 11, 75-85.
• Bezgin, N.Ö., 2017. Development of a New and an Explicit Analytical Equation that Estimates the Vertical Dynamic Impact Loads of a Moving Train. Procedia Engineering, 189, 2-10.
• Bezgin, N.O., 2018. Application of a New Concept and a Method to Estimate the Vertical Impact Forces on Railway Tracks due to Track Stiffness Variations. 97th Annual Meeting of the Transportation Research Board, Washington, DC.
• Bezgin, N.Ö., 2018. Proposal of a New Analytical Method to Estimate the Vertical Impact Forces on Railway Tracks due to Changes in Track Profile and Track Stiffness. 5th International Conference on Road and Rail Infrastructure CETRA, 837-845.
• Bezgin, N.Ö., Wehbi, M., 2019. Advancement and Application of the Bezgin Method to Estimate Effects of Stiffness Variations Along Railways on Wheel Forces. Transportation Research Record, 2673(7), 248-264.
• Bruni, S., Anastasopoulos, I., Alfi, S., Van Leuven, A., Gazetas, G., 2009. Effects of Train Impacts on Urban Turnouts: Modelling and Validation Through Measurements. Journal of Sound and Vibration, 324(3-5), 666-689.
• Choi, J., 2013. Influence of Track Support Stiffness of Ballasted Track on Dynamic Wheel-Rail Forces. Journal of transportation engineering, 139(7),709-718.
• Dahlberg, T., 2010. Railway Track Stiffness Variations–Consequences and Countermeasures. International Journal of Civil Engineering, 8(1), 1-12.
• Dukkipati, R.V., Dong, R., 1999. The Dynamic Effects of Conventional Freight Car Running Over a Dipped-Joint. Vehicle System Dynamics, 31(2), 95-111.
• Isolgomma, “Sleeper pads” [Online]. Available: https://www.isolgomma.com/sleeper-pads/. [Accessed July 7, 2020].
• Johansson, A., Nielsen, J. C. O., Bolmsvik, R., Karlström, A., Lundén, R., 2008. Under Sleeper Pads—Influence On Dynamic Train–Track Interaction. Wear, 265 (9-10), 1479-1487.
• Kaewunruen, S., Remennikov, A., 2007. Low-Velocity Impact Analysis of Railway Prestressed Concrete Sleepers. Proceedings of the 23rd Biennial Conference of the Concrete Institute of Australia: Design, Materials, and Construction, 659-668.
• Khajehdezfuly, A., 2019. Effect of Rail Pad Stiffness on the Wheel/Rail Force Intensity in a Railway Slab Track with Short-Wave Irregularity. Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, 233(10), 1038-1049.
• Lakušic, S., Ahac, M. and Haladin, I., 2010. Experimental Investigation of Railway Track with Under Sleeper Pad. 10th Slovenian Road and Transportation Congress, Slovenia.
• Li, M.X.D., Berggren, E.G., 2010. A Study of yhe Effect of Global Track Stiffness and Its Variations on Track Performance: Simulation And Measurement. Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, 224(5), 375-382.
• Liu, K., De Roeck, G., Lombaert, G., 2009. The Effect of Dynamic Train–Bridge Interaction on the Bridge Response During a Train Passage. Journal of sound and vibration, 325(1-2), 240-251.
• López Pita, A., 1984. Posibilidades En La Reducción De Los Costes De Mantenimiento De La Calidad Geométrica De Una Vía, Mediante La Introducción De Nuevos Criterios En Su Diseño. XVI Pan American Railway Congress, 416-463.
• Markine, V.L., Steenbergen, M.J.M.M., Shevtsov, I.Y., 2011. Combatting RCF on Switch Points by Tuning Elastic Track Properties. Wear, 271(1-2),158-167.
• Ngamkhanong, C., Kaewunruen, S., 2020. Effects of Under Sleeper Pads on Dynamic Responses of Railway Prestressed Concrete Sleepers Subjected to High Intensity Impact Loads. Engineering Structures, 214,110604.
• Nicklisch, D., Kassa, E., Nielsen, J., Ekh, M., Iwnicki, S., 2010. Geometry and Stiffness Optimization for Switches and Crossings, and Simulation of Material Degradation. Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, 224(4), 279-292.
• Pålsson, B.A., Nielsen, J.C., 2015. Dynamic Vehicle–Track Interaction in Switches and Crossings and the Influence of Rail Pad Stiffness–Field Measurements and Validation of a Simulation Model. Vehicle System Dynamics, 53(6), 734-755.
• Remennikov, A, Kaewunruen, S., 2005. Determination Of Dynamic Properties Of Rail Pads Using Instrumented Hammer Impact Technique. Acoustics Australia, 33 (2), 63-67.
• Teixeira, P.F., 2004. Contribución A La Reducción De Los Costes De Mantenimiento De Vías De Alta Velocidad Mediante La Opitimización De Su Rigidez Vertical. Doktora Tezi. Universitat Politècnica de Catalunya, İspanya.
• Wu, T.X., Thompson, D.J., 2004. The Effects Of Track Non-Linearity On Wheel/Rail İmpact. Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, 218 (1), 1-15.
• Zhai, W., Cai, Z., 1997. Dynamic Interaction Between a Lumped Mass Vehicle and a Discretely Supported Continuous Rail Track. Computers & structures, 63(5), 987-997.