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

Abstract

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.

Keywords

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

DEMİRYOLU HATLARINDA ELASTİK PED KULLANIMININ DİNAMİK DARBE KUVVETLERİ ÜZERİNDEKİ ETKİSİ

Abstract

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.

Keywords

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

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