Blaxland Crossing Bridge - Bridge Bearing Replacement Project

View from Warragamba Lookout

Wollondilly Shire Council and Penrith City Council wishes to advise that temporary changed traffic conditions will be in place at the Blaxland Crossing Bridge (also known as Wallacia Bridge & Silverdale Road Bridge) commencing in June 2016.

As part of Wollondilly Council’s asset management plan, it has been identified that the bridge bearings need to be replaced.

Due to the work required the following restrictions have been put in place:

  • 40kph speed limit on the bridge during replacement work
  • restricted access for 19m B-Doubles, B-Double access by permit will continue
  • 38t load limit without permit from June 30
  • Permit required for vehicles heavier than 38t but not exceeding 55t, from June 30
  • Fuel and quarry trucks will be able to access under the permit system

Wollondilly and Penrith Councils understand that this temporary restriction may cause disruption to businesses using the bridge as part of their route to deliver or receive goods/services. Both Councils are committed to working with local and regional businesses to ensure any disruption is kept to a minimum. 

Permits for use between 38 and 55t will be issued that will be extended pending monitoring of the bridge.

Access for NSW Fire & Rescue, Rural Fire Service, garbage trucks and buses will not be affected.

Motorists are advised to expect delays and to exercise caution within the area whilst the works are being carried out.

For further information contact Rod Bray, on 4677 1100 or council@wollondilly.nsw.gov.au 

Downloads

Application for Permit to Exceed Sign Posted Load Limit (Please allow 5 business days for normal processing of permit applications)

The estimated cost of the total project has been estimated at $950,000. This cost will be split on a 50/50 basis between Wollondilly Shire Council and Penrith City Council as part of their asset management programs.

The Blaxland Crossing Bridge is almost 50 years old and whilst the bridge is still safe to travel on with the reduced speed limit, without major repair work it would continue to deteriorate and eventually become unserviceable. With this in mind, Wollondilly and Penrith Councils scheduled the replacement of the bridge bearings, which are nearing the end of their design life-span.

As a part of the preparation for this work, the bridge was inspected and tested to confirm the condition of the bearings and the bridge structure. This testing confirmed that the bridge bearings were not functioning correctly and did require replacement. Due to the age of the bridge the bearings cannot easily be replaced. Additional investigations were undertaken to determine the best method of replacement.

It was also found that in its current condition the bridge was not suitable for unrestricted higher load vehicles and that load restrictions should be imposed to prevent the bridge deteriorating further at a faster rate.

The storm event of 5 June 2016 occurred after the initial investigations; however, a detailed assessment found that no structural damage was caused as a result of the storm. There was some damage to the footpath panels on the bridge which have since been fixed.

For further information on this Project or vehicle permits please contact Council P: 4677 1100 or E: council@wollondilly.nsw.gov.au

It is expected that the investigation, detailed design, tendering and construction works will take until at least February 2018 to be completed and the project will be staged as per below:

When Description Status  Comments
17 June 2016 Site traffic management warning signs installed (warning of load limit being applied) Complete  
21 June 2016 Full site traffic management plan implemented Complete  
Advance warning signage at critical driver decision points warning of load limit   Additional sign installed at Intersection Farnsworth and Silverdale Road
Onsite road works signage    
Issuance of load permits Continuing 955 permits issued to date (as of 23 June 2017)
June to November 2016 Detailed investigation and design of bearing replacement Complete  
Mid November to Mid December 2016 Call tenders for replacement of bridge bearings Complete Seven tenders were received by the 19 December 2016
January to May 2017 Tender review process. Consultation and approvals with utility service providers Complete Sydney Water require Council to obtain approval via the FIFM (Flow Isolation and or Flow Management) process
June 17 Rejection of all tenders Complete All tenders rejected due to required changes in specification and scope
June to September 2017 Sydney Water Approval Process - FIFM (Flow Isolation and or Flow Management) Ongoing Subject to Sydney Water review and approval
August 2017 Accept tender for works Complete Awarded contract to Complex Civil
August 2017 Works planning and approvals by successful contractor Commenced Environmental Management Plan, Traffic Management Plan, Detailed Works Plan & Program
September 2017 Community Engagment regarding traffic management during works Scheduled

Thursday 21 September at the Warragamba Town Hall, from 6.30pm to 8.30pm

 November 2017 Commence Bridge bearing works Scheduled Pending final approval from Sydney Water and completion of Works Planning.
February 2018 Completion of Bridge Works  Scheduled  
February 2018 Testing of bridge post repairs to determine final required load limits and communicate results to the community Scheduled  

 

 

The initial site investigation, by consultant bridge engineers, recommended that due to the deteriorated condition of the bearings, the following restrictions should be imposed:

  • A 38t general load limit.
  • Heavier vehicle access up to 55t by permit (issued from Wollondilly Shire Council).
  • Speed limit across and in the vicinity of the bridge lowered to 40kph.

The ultimate bridge load limit will be reviewed once the works are complete. Wollondilly and Penrith Councils have worked with the National Heavy Vehicle Regulator (NHVR) regarding the loading issue, and the Gazetted B-Double route across the bridge has been removed.

Temporary speed limit restrictions are facilitated by the Roads Act 1993 and have been implemented to minimise the dynamic loading impacts on the bridge structure so that further damage to the bridge bearings are prevented. The road work signage is a requirement of the Roads Act and also serves as a reminder to motorists to take care when driving over the bridge.

Imposing a limit on the number of vehicles allowed on the bridge at any given time is not feasible. Both Councils will continue to monitor the bridge and if further deterioration occurs the current load and speed limit restrictions will be reviewed.

Wollondilly and Penrith Councils understand that this temporary restriction may cause disruption to businesses that use the bridge as part of their route to deliver or receive goods/services. Both Councils are committed to working with local and regional businesses directly to ensure any disruption is kept to a minimum.

Access for NSW Fire & Rescue, Rural Fire Service, garbage trucks and buses are not affected by these limits.

Permits are available for anyone with a heavy vehicle and access to the bridge will be permitted to those with a legitimate use, including local businesses.

Permits for use between 38t and 55t will be issued for up to the end of June 2018, and may become redundant pending completion of the works and final testing. The final testing will confirm the recommended loading restriction to be imposed.

After a competitive tender process, the contract for the bearing replacement has been awarded to Complex Civil.

As at mid-September, preliminary works have commenced with a final approval from Sydney Water still pending before a commencement date for site works can be confirmed. Complex Civil's preferred commencement is early November 2017.

The scheduled program includes a 10 week construction period, which will include:

  • Carry out 3D laser survey of existing piers to allow detail design to commence. This highly detailed survey allows the steel bearing supports to be fabricated to exact measurements prior to installation.
  • Design bespoke steel bearing support assemblies for each pier.
  • Install temporary diversion pipes across the bridge for water main and sewage pumping main, to eliminate risk to vital infrastructure during the works. These works will involve excavations at each end of the bridge and associated traffic control (stop / slow system).
  • Install access scaffold beneath the bridge deck to allow access to all piers and abutments. A walkway will be installed from the east bank for access.
  • Install new steel bearing support assemblies. These will be transported onto the scaffold and hoisted into place at each pier, following which they will be permanently attached with tensioned bars to effectively ‘clamp’ them into place.
  • Replace bridge bearings. This is a staged process which will be carried out one pier at a time:
    1. Install hydraulic jacks between pier and bridge beams.
    2.  Install a new uplift / lateral restraint bracket between new bearing support assembly and existing bridge.
    3.  Sever and remove existing uplift restraint .
    4.  Raise section of bridge hydraulically by 10mm.
    5.  Remove old failed bearings and install new elastomeric rubber bearings.
    6.  Lower bridge onto new bearings.
    7.  Remove jacks, proceed to next pier.
  • During the above operation, a section of the bridge will be supported on the hydraulic jacks. To maintain stability and safety, traffic will be reduced to single lane operation at 40 kmh along the centre of the bridge. There will be some stop / slow delays required during the works but no planned detours.
  • On completion of bearing works, access scaffold will be removed.
  • Inspect water main and sewage pumping main – when proven unaffected these will be reconnected and the temporary diversion pipes removed.

 The risks that will need to be managed include:

  • Damage to existing bridge and stability during jacking operations.
  • Damage/disruption to water or sewer services.
  • Management of traffic.
  • Demolition of existing restraint.
  • Working over water.
  • Working at heights.

A majority of the works are proposed to be accessed by scaffold and barge. Traffic Control will be required, particularly during jacking operations and will require reducing the available width to one centralised lane managed with stop / slow traffic control. Once the jacking procedure is complete, two way traffic flow can resume.  All works are proposed to be done during daylight hours.