Long bearers are used at switches and crossings (S&C) to maintain the gauge and prevent relative lateral movement between the rails for all possible routes a train may take. Traditionally, these bearers are formed of continuous timber or pre-tensioned steel reinforced concrete beam, up to 6 m or more in length. However, restrictions on the availability and cost of access time for track works have led to the development of new jointed bearers. These allow modules of S&C to be pre-constructed and loaded onto road/rail vehicles for joining on site, reducing the track access time required and saving money. Jointed bearers have elements that are not much longer than plain line ties (<3.0 m). However, joining the bearer elements presents challenges. Two types of solution are currently available: (1) flexible joints—which allow some relative rotation and vertical movement between the connected ends of the bearer parts; (2) rigid joints, which may give a bending stiffness close to that of a continuous beam. The type of joint has implications for crossing performance, and the existence of alternative designs suggests that a universal solution has not been identified. This paper presents results from a laboratory study carried out to evaluate the effect of joint type on performance. In testing, repeated loading representative of >1 million cycles of a 20 tonne (20,000 kg) axle load was applied to the railseats of bearers supported on a ballast bed. Settlements and resilient movements at locations along the bearers were measured and analysed. The results show that the type or absence of a joint significantly affects the settlement and resilient deflections along the bearer length.

Performance of Jointed S&C Bearers / Khan, A. S.; Ferro, E.; Le Pen, L.; Powrie, W.. - ELETTRONICO. - 165:(2022), pp. 49-61. (Intervento presentato al convegno ICTG 2021 4th International Conference on Transportation Geotechnics tenutosi a Chicago, USA nel 23th-26th May 2021) [10.1007/978-3-030-77234-5_5].

Performance of Jointed S&C Bearers

Ferro, E.;
2022-01-01

Abstract

Long bearers are used at switches and crossings (S&C) to maintain the gauge and prevent relative lateral movement between the rails for all possible routes a train may take. Traditionally, these bearers are formed of continuous timber or pre-tensioned steel reinforced concrete beam, up to 6 m or more in length. However, restrictions on the availability and cost of access time for track works have led to the development of new jointed bearers. These allow modules of S&C to be pre-constructed and loaded onto road/rail vehicles for joining on site, reducing the track access time required and saving money. Jointed bearers have elements that are not much longer than plain line ties (<3.0 m). However, joining the bearer elements presents challenges. Two types of solution are currently available: (1) flexible joints—which allow some relative rotation and vertical movement between the connected ends of the bearer parts; (2) rigid joints, which may give a bending stiffness close to that of a continuous beam. The type of joint has implications for crossing performance, and the existence of alternative designs suggests that a universal solution has not been identified. This paper presents results from a laboratory study carried out to evaluate the effect of joint type on performance. In testing, repeated loading representative of >1 million cycles of a 20 tonne (20,000 kg) axle load was applied to the railseats of bearers supported on a ballast bed. Settlements and resilient movements at locations along the bearers were measured and analysed. The results show that the type or absence of a joint significantly affects the settlement and resilient deflections along the bearer length.
2022
Advances in Transportation Geotechnics IV Lecture Notes in Civil Engineering, vol. 165
Cham, Switzerland
Springer Nature Switzerland AG
9783030772338
Khan, A. S.; Ferro, E.; Le Pen, L.; Powrie, W.
Performance of Jointed S&C Bearers / Khan, A. S.; Ferro, E.; Le Pen, L.; Powrie, W.. - ELETTRONICO. - 165:(2022), pp. 49-61. (Intervento presentato al convegno ICTG 2021 4th International Conference on Transportation Geotechnics tenutosi a Chicago, USA nel 23th-26th May 2021) [10.1007/978-3-030-77234-5_5].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11572/323638
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