It's time to replace the Sydney Harbour Bridge





It's time to replace the Sydney Harbour Bridge

After 80 years of distinguished service, the Sydney Harbour Bridge is entering her twilight (ABC News)

When the Sydney Harbour Bridge was built 80 years ago, it joined together what had been a divided city, with almost incalculable social and economic benefits. But now, it has become a liability, writes Ross Cameron.

My mother texted me last week: "It feels weird to have a son who wants to replace the Sydney Harbour Bridge."

Five of my business friends and associates, whose opinion I respect, told me separately, "We love your M4East concept, but leave the bridge out - people won't cope."

Well, boys and girls, I'm really sorry but the Sydney Harbour Bridge has to be replaced. Yes, it is iconic and World Heritage listed, but it is in decay and has been outgrown by the city it serves.

I must have missed the chemistry lecture that explained, "In the early 20th century, Sydney alchemists invented a form of steel that doesn't rust or oxidise and will last forever." Everything you can see is perishing - including the Sydney Harbour Bridge.

It has to be replaced sometime. Our bridge will not be there in a hundred years - at least not the same steel. Here are the arguments for replacing the bridge now.

When the bridge was opened, New South Wales had a total car pool of 10,000 and a population of 1 million. This week, over a million cars will pass over the bridge, from a city population of 4.6 million and growing at over 65,000 a year.

After 80 years of distinguished service, our fair lady is entering her twilight and is now forced beyond its design limits every weekday. It is one of the three most extreme "choke" points on Sydney's mass transit network (the other two being the Central to Strathfield rail corridor and the M4). Our inability to move people across the harbour holds hostage the rest of Sydney's transport network.

Dr John Bradfield selected the design in part because of its ability to later bolt on a second deck of road and rail under the existing suspension platform. (It was also designed, like all well-engineered structures, with a view to its eventual replacement, in a reversal of the method of its assembly.) The NSW Government received a proposal to add the second deck in the late 1990s. The proposal was rejected, because the assay made clear that the ageing span was no longer sound to safely bear the weight of the second tier.

The bridge is 39,000 tonnes of steel, prefabricated in Scotland and shipped for assembly in parts. It was known as Sydney's "iron lung" because its erection gave an income to thousands of families during the depression. The whole city filled with hope as the skyline changed, each new section reaching out to eventually close in the centre. Its completion meant that a city divided was at last joined, its social and economic benefits almost defying calculation.

The 6 million rivets (like buttons on a shirt) were heated in coking coal-fuelled furnaces on the Luna Park site before modern welding techniques (which are more like "stitching"). The rudimentary furnaces allowed differing levels of penetration by steel-damaging nitrogen and ash. Each rivet now has variable load bearing and surface qualities. Some of the "buttons" have started to pop. In March this year, a fastening failure caused a two-square-metre steel panel to shear off the arch - it could easily have fallen onto the carriageway below.

Roads and Maritime Services made no comment about the extent to which that failure signals ongoing risks from an 80-year-old structure. I understand that reticence - nobody reading this article should panic. But our bridge has "issues". The fact that the bridge replacement program is not included in the 20-year plan of Infrastructure NSW is a serious omission.

The bridge could stand for another decade or two and continue to give service but prudent asset maintenance means all of those rivets should now be replaced. Many are covered by external steel panels and buried deep within girders and beams. The metals, dust, paint, salt spray and dirt combine to turn our bridge into a battery, carrying electric currents up and down the arch to accelerate the oxidising and corrosion of steel standing over a body of water. (Vast stretches of rust underneath are visible to the naked eye). Assuming we continue a maximum toll of $4, in one direction only, each car needs to travel over and back 250 times to raise the revenue to replace one rivet.

Working on the assumption that the people of Sydney are not mature or rational enough to consider replacing the bridge, the NSW Government has developed another plan - a new two-lane rail tunnel crossing. The easy route under the harbour has already been taken by the existing cross harbour tunnel. The only route available to us now is very deep, reaching 80m below sea level. To safely reach that depth, such a tunnel would have to begin as far back as Redfern and climb to St Leonards - still as steep as any mass transit train path in the world. The project is dangerous and difficult and extravagantly expensive - between $8bn and $10bn. The rail tunnel offers no benefit to road users and will still leave us with a vast sinkhole of maintenance cost on the bridge and likely near term replacement (or could it be closed down to commuters with the built form left as a heritage relic? Perhaps with a new bridge somewhere else, competing for sight lines?).

You can buy a brand new super tanker, 45,000 tonnes of steel, from a Japanese or Korean shipyard, for $80m. We can probably procure a brand new, welded replica of our Sydney Harbour Bridge, with a second deck below, carrying 16 lanes of road and eight lanes of rail, with change out of $300m. We can erect the new structure as a bypass on the western side, de-commission and remove the original, then slide the "son of SHB" across on a bearing foundation, clicking into the old alignment - with minimal commuter disruption.

We might choose, after public discussion, to make it a few metres wider and taller, with adequate clearance for the super yachts and naval vessels to pass underneath, while preserving the same colour, profile and alignment. We can then spend the savings - where they should be spent - integrating new road and rail capacity desperately needed on either side, including redeveloped stations on the City Circle and between Milsons Point and St Leonards, into a much more functional and resilient mass transit system for Sydney.

In 1789 Erasmus Darwin - grandfather of Charles - prophesied in poetry a "proud arch" spanning Sydney Harbour - 134 years before the first rivet was forged. John Bradfield cited Darwin's poem at the opening ceremony. So there is a sense in which the bridge is immortal - it comes to us from before our time, and will go on, adapted to the city it serves, over centuries to come. Each generation can be faithful to the immortal arch, while replacing the molecules that make up its span. We have a duty to our heritage but also to the millions of Australians as yet unborn who will inherit, and must live and move in, the city we leave.

Ross Cameron is a former federal MP and Macquarie Banker, now Chairman of Towncars.com and AspireSydney infrastructure consortium (in which he has a financial interest). AspireSydney's Unsolicited Proposal in September 2012 to the NSW Government to evaluate a PPP on a replacement and upgrade of the Sydney Harbour Bridge received no response.


 














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