PROPOSED NIGHT MAINTENANCE WORK ON WINDSOR BRIDGE COMMENCING 26 AUGUST 20I8
On the weekend of 29 July 2018, Windsor residents were letterboxed with flyers notifying of the RMS’s intention to undertake nighttime work on Windsor’s historic 1874 bridge.
Specifically, the leaflet said the RMS, "will be making essential repairs to the concrete bridge joints on Windsor Bridge,"
The notification advised the work would involve:
Unfortunately, the government has ignored this practical and sensible solution and continues to insist on the total destruction of the historic and heritage-listed bridge.
Despite some concerns about how bumpy the bridge deck had become, because of the long-standing neglect of the bridge, the planned maintenance work was unexpected.
Furthermore, given its intention to demolish the bridge it is not clear to the lay person why, in the interim, the RMS were not simply planning to cover the deck, including the joints, with a new layer of asphalt to cover and smooth out the bumps.
The RMS advised work was scheduled to start 26 August, finish 30 September 2018.
CAWB has, for some time been aware of rumours the RMS was planning to close the bridge to heavy vehicles in early October, but initially ignored them as highly improbable. It seemed extremely unlikely the RMS had been provided with a report advising the bridge was safe for all vehicles, but would suddenly have to be closed to heavy vehicles on a particular date months after the drafting of the report.
Peter Stewart's independent Report on Structural Condition of the existing Windsor Bridge provides valuable information on the subject of the deck joints. On page 17 Mr Stewart advises,
Currently as the joints are ‘locked up’ the forces from vehicle braking is transferred through the deck to the abutments and not transferred through the piers. (See reproduced RMS diagram below) [B5]
Specifically, the leaflet said the RMS, "will be making essential repairs to the concrete bridge joints on Windsor Bridge,"
The notification advised the work would involve:
- Quick cut sawing
- Jackhammering
- Grinding
- Compacting.
- In 2008 consultants preparing a Statement of Heritage Impact said,
- In 2012 the RMS said (QoN, Perry) “Total maintenance repairs between 1994 and 2012 were $89,614” and
- In 2013 an email from the RMS said from 1994 to 2013 “bridge maintenance cost just over $57,000” (Email dated 28.06.13).
Unfortunately, the government has ignored this practical and sensible solution and continues to insist on the total destruction of the historic and heritage-listed bridge.
Despite some concerns about how bumpy the bridge deck had become, because of the long-standing neglect of the bridge, the planned maintenance work was unexpected.
Furthermore, given its intention to demolish the bridge it is not clear to the lay person why, in the interim, the RMS were not simply planning to cover the deck, including the joints, with a new layer of asphalt to cover and smooth out the bumps.
The RMS advised work was scheduled to start 26 August, finish 30 September 2018.
CAWB has, for some time been aware of rumours the RMS was planning to close the bridge to heavy vehicles in early October, but initially ignored them as highly improbable. It seemed extremely unlikely the RMS had been provided with a report advising the bridge was safe for all vehicles, but would suddenly have to be closed to heavy vehicles on a particular date months after the drafting of the report.
Peter Stewart's independent Report on Structural Condition of the existing Windsor Bridge provides valuable information on the subject of the deck joints. On page 17 Mr Stewart advises,
Currently as the joints are ‘locked up’ the forces from vehicle braking is transferred through the deck to the abutments and not transferred through the piers. (See reproduced RMS diagram below) [B5]
The braking load test undertaken on the bridge supports the theory the bridge is locked up with negligible bending stresses recorded in the piers under the tests indicating that the horizontal forces are being shared by all the piers or being transferred to the abutments. This is fortuitous as the piers, which would otherwise transfer these braking loads, are in a condition whereby they may not be able to withstand the full braking forces (particularly Pier 5 which has significant circumferential cracking of its cast iron caisson).”
Mr Stewart also says,
"Ironically it may be unwise to repair (the joints) to their original design as it would change the load transfer of forces."
On page 18 Mr Stewart advises,
No action has been taken to repair the joints. These repairs should not be done until the cracked piers (piers 5 and 6) have been repaired by providing them with a structural steel jacket as strengthening.”
He also says:
“..the timing of repairing the joints could negatively influence the existing condition...”
At page 16 Mr Stewart says
"...if the bridge structure is changed in the way it distributes the forces then it may well become structurally unsafe." He goes on to say "If the deck joints are opened up as part of a repair process then the piers will have to resist greater horizontal forces which they may not be able to do due to graphitisation and cracking..."
Mr Stewart (page 16) rejects the idea cracks in pier caissons warrant demolition of the bridge, saying:
“The cracks have been there for decades and during that time the bridge has been subjected to severe flooding (overtopped approximately 64 times in 100 years) as well as increases in traffic volumes. The bridge has not exhibited any signs that it is about to fail. The condition of the piers is not a reason alone to demolish the existing bridge, due to the rehabilitation methods available to retain the structure.”
Further to this comment, it is noted the Statement of Heritage Impact for the Hawkesbury River Bridge, Windsor, NSW (2008), prepared by Heritage Concepts for the then-RTA, on page 19, confirms Mr Stewart's advice the cracks have existed for decades, saying, "In November of 1953 an inspection revealed the cracking of a pier’s cylinder. The steelwork was sandblasted and repainted in 1954 at a cost of ₤300 (RTA File 91.1526.1)."
The leaflet distributed to Windsor households provides no further detail regarding the proposed works. There is certainly no reference to providing the piers with a structural steel jacket as strengthening. A photograph of the bridge deck is captioned: "Concrete bridge joint to be repaired on Windsor Bridge".
Mr Stewart's Report (Page 17) also includes a photograph of a deck joint:
In order to clarify whether "Concrete bridge joint to be repaired on Windsor Bridge" meant “opening up the deck joints”, the President of CAWB, Harry Terry, wrote to the head of the RMS (cc Premier and Cabinet, Planning and the Upper House Inquiry into Windsor Bridge) seeking assurance the RMS is not proposing to, in any way, change the load transfer of forces, particularly given the independent advice such action may cause the bridge to become structurally unsafe.
Mr Terry also asked whether the RMS had plans to prematurely close Windsor Bridge to heavy vehicles.
Additionally, Mr Terry requested detailed advice as to what the proposed "essential repairs to the concrete bridge joints on Windsor Bridge" involved.
CAWB will publish the response as soon as it is received.
