The replacement of the affectionately known ‘Hole in the Wall’ Gowrie Gates Bridge involved reworking the pre-existing twin steel, transom top rail underbridge that carries the Main Northern Rail Line, running over the New England Highway. This project was completed in conjunction with the ARTC/RMS as a joint-funded project.
Scope of Work
- Replacing the existing bridge with precast, post-tensioned main girders and precast, pretensioned slab topped with in situ concrete deck single span bridge, to be constructed on site. This was then lifted to slide into place during a November 96 hour possession.
- Realigning and some formation reconditioning will be included in the works on the existing Up and Down tracks of the Main Northern Rail Line
- Included in the contract is the upgrade of the New England Highway (NEH) beneath the bridge, to include three metre wide shoulders
- The construction requires the diversion of traffic on the NEH to a temporary side-track crossing during track possessions, and consequent NEH closure. This track includes a ‘Drop in Span’ steel bridge to span the railway during possessions
- The successful execution of a complex construction within, and adjacent to, the extremely busy Singleton to Muswellbrook rail line during possession and non-possession times (dominated by coal trains)
- Coordinating with subcontract designers to generate temporary designs for piling pads and sheet piling walls
- Extensive coordination with SMEC and girder manufacturer Structural Concrete Industries (SCI) to formulate connection detail, allowing the joining of girders supplied and delivered in three sections
- Delivering the works within a 56-week program, with limited rail possession dates and times. As a result, the works required meticulous programing and organisation by the site team leading up to, and during possession, to meet PC date
- Establishment of crane pads and coordination of 750 tonne crane to allow for 160 tonne girder lifts on temporary headstocks, prior to bridge slide
- Coordination of a post-tensioning subcontractor to allow for girders to be post-tensioned on-site while being supplied in three sections
- Coordination of a post-tensioning subcontractor to slide the 400t bridge into place within the 96 hour possession
- Extensive traffic control staging required on the NEH to allow for widening of approach and pavement reconstruction