Mechanical Engineering, bridge bearings, structural engineering Specialists In Structural Movement Control
Mechanical Engineers Specialising In Structural Movement Control
Supplied: 36 D series Line Rocker Bearings
& Supervision of Installation
Challeymead Bridge
Ekspan Ltd. was employed in 2002 to conduct an inspection of the existing Glacier Line Rocker bearings installed in the early 1970s. The recommendation following this survey was that the bearings could be refurbished provided the load and articulation criteria had remained constant with the original design. Due to the extent of other remedial work & an increase in axle loadings on the structure the client opted for the full replacement of the bearings. The articulation of the bridge remained constant although the half of the bearings required an increased load capacity. This was potentially problematical due to the limited available space and the limitation on the jacking and volume of hydro-demolition works that could be permitted.
Job Brief
Background Information
Project Team
Client: Wiltshire County Council
Client Consulting Engineer: Ringway Parkman
Main Contractor: Dean & Dyball
Start Date: Spring 2003
Completion Date: Summer 2004
Bearings
Ekspan Ltd. supplied 36 Line Rocker bearings to the project. All bearings were designed in line with the original Glacier design although 18 bearings had to be designed as segmental. This was due to the restricted jacking permissible and the need to minimise the hydro-demolition. The bearings were designed such that the existing dowel positions and fixing holes could be utilised due to the available height restricting additional drilling into the structure. Due to the tight
tolerances that the contractor had to work within Ekspan Ltd. were called in to supervise the installation of some of the bearings and provide on-site technical support.
All of the bearings supplied incorporated the following features:
1. TIG Welded mirror polished stainless steel mating sliding surfaces.
2. Dimpled and greased PTFE sliding surfaces.
These features enhance bearing life and reduce the risk of premature replacement being required. These quality features are included as standard on all Ekspan Ltd. pot bearings.
Ekspan's Solution