Blaxland Crossing Bridge - Bridge Bearing Replacement Project

View from Warragamba Lookout

As part of Wollondilly Council’s asset management plan, it had been identified that the bridge bearings needed to be replaced. This has now been done.

Permits were in place for use between 38 and 55t however we note that these permits are no longer required and current permit holders have been advised. 

Access for NSW Fire & Rescue, Rural Fire Service, garbage trucks and buses was not 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 Council, on 4677 1100 or council@wollondilly.nsw.gov.au 

The Blaxland Crossing Bridge is approximately 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.

The initial site investigation, by consultant bridge engineers, recommended that until the bearings  are replaced , the following restrictions were to 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 works are now at a stage the temporary restrictions are no longer required. 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.

Wollondilly and Penrith Councils acknowledge that the temporary restriction may have caused 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.

After a competitive tender process, the contract for the bearing replacement has been awarded to Complex Civil. Complex Civil's have commenced work.

The scheduled program includes:

  • Carry out 3D laser survey of existing piers to allow detail design to commence (complete). 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 (pre-fabrication off site – commenced late 2017).
  • 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.

 

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.

It is expected that the investigation, detailed design, tendering and construction works will take until at least June 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 November 2017

Sydney Water Approval Process

Complete

Designs approved by Sydney Water

August 2017

Accept tender for works

Complete

Awarded contract to Complex Civil

August 2017

Works planning and approvals by successful contractor

Complete

Environmental Management Plan, Traffic Management Plan, Detailed Works Plan & Program

September 2017

Community Engagement regarding traffic management during works

Complete

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

November 2017

Vegetation clearing and utility service locating (incl. depths)

Complete

Service information required to confirm shop drawings to pre-fabricate components of temporary pipework

December to January 2018

Ordering and pre-fabrication

Complete

Ordering of pipework components and pre-fabrication of brackets and pipe sections

January 2018

Commence Bridge bearing works

Complete

 

July/August 2018

Completion of Bridge Works 

Scheduled

 Permits no longer required

 

 

 

 

 

 

 

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