Sydney harbour immersed tube tunnel.

Sydney / New South Wales Transport Discussion
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eddy
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Sydney harbour immersed tube tunnel.

Post by eddy »

I have an idea that may save the NSW government millions on the western Sydney immersed tube tunnel while making it more eco friendly.

In the same way as the Nowra bridge is being built from the southern end the immersed tube could be built with ballast tanks which could be pumped out when it is about to be pushed to reduce the resistance.

As this area is very, very polluted the trench can be slowly dredged with spoil taken by barge well out to sea to be dumped.
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Re: Sydney harbour immersed tube tunnel.

Post by BDAT »

Hi Eddy,
You do know that the current Sydney Harbour road tunnel was built in a similar manner to what you are proposing.
The approaches were built and a trench excavated across much of the Harbour. The large caissons were built at Port Kembla.
Towed to Sydney and sunk in the Trench. The large Basin at Port Kembla is now part of the Harbour down there.
Win Win.
Cheers
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Re: Sydney harbour immersed tube tunnel.

Post by eddy »

BDAT wrote: Sat Sep 25, 2021 12:30 am Hi Eddy,
You do know that the current Sydney Harbour road tunnel was built in a similar manner to what you are proposing.
The approaches were built and a trench excavated across much of the Harbour. The large caissons were built at Port Kembla.
Towed to Sydney and sunk in the Trench. The large Basin at Port Kembla is now part of the Harbour down there.
Win Win.
Cheers
Yes, I was fully aware of that but because of the extra pollution and higher EPA standards I could not see how they were giong to do it and after seeing how they are building the Nowra bridge, with the same method as Gerringong one, plus I saw the video that said they had no room to build the cassions, the idea just came to me in bed glory to god as I am not an engineer.
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Re: Sydney harbour immersed tube tunnel.

Post by eddy »

As traditional immersed tube uses gaskets between sections perhaps each section could have a gasket attached when built to allow vertical flex which in turn would allow the sections to be built above the water line?
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Re: Sydney harbour immersed tube tunnel.

Post by mubd »

Congrats eddy, for once they have listened to you!
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Re: Sydney harbour immersed tube tunnel.

Post by eddy »

There are a lot of people looking at what I suggest and it may be cheaper than the immersed tube in the download.
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Re: Sydney harbour immersed tube tunnel.

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After seeing how Batemans bay used the tide to lift off the sections I was wondering if a barge with extended longwall chocks, so they could be lowered, could take some of the weight lowering resistance on the Nowra bridge making it easier to push ??

Just a stupid thought ha ha.
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Re: Sydney harbour immersed tube tunnel.

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I got a nice thank you email from Terry McSweeney regarding my suggestion to Gladys for the incremental immersed tunnel.
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Re: Sydney harbour immersed tube tunnel.

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Went for my daily walk to check out the Nowra bridge and for the first time I saw them pushing it and asked another old guy how they did it with it being so heavy and he told me they put slippery things on each support as it was being extended which I observed.

Had a look at both ends of the new incrementally immersed Sydney harbour tunnel but only saw a bit at the golf club and nothing at Ballast point but I recommend a walk around there as it is beautiful.
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Re: Sydney harbour immersed tube tunnel.

Post by eddy »

Here is a YouTube of incremental bridge building https://www.midasbridge.com/en/blog/cas ... hed-bridge.

It will be very interesting how they do the incrementally launched western Sydney harbour tunnel.
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Re: Sydney harbour immersed tube tunnel.

Post by eddy »

This https://www.smh.com.au/national/nsw/syd ... 58v52.html says they are looking at a couple of contractors to build the incrementally launched western Sydney harbour crossing.

After watching how the Nowra bridge is built (10 meter push yesterday) I think they should give the contract to them as they are terrific in my opinion.

PS
As the concrete has to set before each push perhaps if they decide early it will give them time to set up two parallel sites to be done alternatly.
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Re: Sydney harbour immersed tube tunnel.

Post by eddy »

Perhaps as the western Sydney harbour incrementally immersed tunnels may have far less resistance than building Nowra bridge the concrete sections could be made longer to allow the twin tunnels to be built faster.
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Re: Sydney harbour immersed tube tunnel.

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Tomorrow they are going to start early work on the environmentally friendly world first incrementally launched immersed western Sydney harbour tunnel https://caportal.com.au/rms/wht/upcomin ... 24-january
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Re: Sydney harbour immersed tube tunnel.

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At 0.16 it shows the northern tunnel entrances. https://www.youtube.com/watch?v=DWjHvuU0Agk
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Re: Sydney harbour immersed tube tunnel.

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I wonder if Canada will do it like Sydney or the old expensive way https://www.newcivilengineer.com/latest ... 0-02-2022/
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Re: Sydney harbour immersed tube tunnel.

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When they wanted to do it like the original tunnel it was so risky they allowed just $5b for the risk https://www.smh.com.au/national/nsw/rev ... xcy6a.html

By using the risk free incrementally launched immersed tunnel I cannot see how it cannot be completely done for that so I hope critics will stop saying that the bridge will need extra tolls.

PS
Originally I was against this proposal as I could see too many problems but with cheap risk free incremental launching, electric vehicles and trucks saving on exhaust due to a free run I now think it should be done ASAP
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Re: Sydney harbour immersed tube tunnel.

Post by eddy »

I noticed on the footy field at Bomaderry they have removed all the topsoil to upgrade it and it got me thinking that assuming the western Sydney harbour incrementally immersed tunnel would be about six meters high and it has to be started above the waterline perhaps the topsoil could be removed temporarily to allow fill to achieve the needed height above the waterline and then replaced.
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Re: Sydney harbour immersed tube tunnel.

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To reduce pollution they try to keep the grade as low as possible https://chiefscientist.nsw.gov.au/__dat ... Sydney.pdf so with the elevation of Birchgrove oval being 10m with the distance to the path 200m that gives a grade of an acceptable 5% so there may not be much fill needed to build above the water line and this could mainly be excavated material from the roadheader used to drive the slope to the waters edge from where the same slope could continue using a cutter dredge reaching 35m below sea level well before the shipping lane.

Looking at cutter dredges I think perhaps the Van Oord Artemis https://www.youtube.com/watch?v=qBCfX-XRM1A may be the shot as it can cut rock right to the waters edge and reach the required depth.


Although I am very interested in this, people with far more knowledge than me have this all worked out but it may be food for thought.
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Re: Sydney harbour immersed tube tunnel.

Post by eddy »

I bumped this up to point out how important it is to drive the slope across Birchgrove oval to the waters edge before the Van Ord Artemis breaks through and floods the slope.

This may be of interest to those designing the western Sydney harbour incrementally launched immersed tunnel https://austroads.com.au/latest-news/ev ... ad-tunnels

PS.
If a positively ventilated emergency escape was included on either side of the immersed tunnel, cyclists could enter through an airlock and be blown across the harbour.
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Re: Sydney harbour immersed tube tunnel.

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As the team doing the Nowra incrementally launched bridge will be finished in a few months perhaps if we can do the grade to the waters edge now they can move straight there taking their expertise with them.
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Re: Sydney harbour immersed tube tunnel.

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Here are some good videos on the western harbour tunnel https://caportal.com.au/rms/wfu/register
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Re: Sydney harbour immersed tube tunnel.

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To avoid building a cofferdam on the northern side the tunnel can be driven to the waters edge and later holed into it with the Artemis https://www.youtube.com/watch?v=qBCfX-XRM1A
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Re: Sydney harbour immersed tube tunnel.

Post by Swift »

They should reclaim the bus lane and private motor vehicle lane and reinstate the railway lines that the DMR stole for the Cahill Expressway in the 1950s and use the wasted tunnels to Wynyard and give Wilson car parks the boot and build the damned northern beaches heavy rail as was originally planned. Then add another deck under the harbour bridge for the self indulgent car commuters to use the CE or decomission it and send the cars elsewhere and turn the deck into a piazza with views of the harbour.
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Re: Sydney harbour immersed tube tunnel.

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Swift wrote: Thu Apr 07, 2022 7:49 pm They should reclaim the bus lane and private motor vehicle lane and reinstate the railway lines that the DMR stole for the Cahill Expressway in the 1950s and use the wasted tunnels to Wynyard and give Wilson car parks the boot and build the damned northern beaches heavy rail as was originally planned. Then add another deck under the harbour bridge for the self indulgent car commuters to use the CE or decomission it and send the cars elsewhere and turn the deck into a piazza with views of the harbour.
Yes mate, after the western Sydney harbour tunnel is completed there are many things we can use the bridge for apart from the fact it had the whole of Sydney gridlocked after an accident recently.
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Re: Sydney harbour immersed tube tunnel.

Post by Transtopic »

Swift wrote: Thu Apr 07, 2022 7:49 pm They should reclaim the bus lane and private motor vehicle lane and reinstate the railway lines that the DMR stole for the Cahill Expressway in the 1950s and use the wasted tunnels to Wynyard and give Wilson car parks the boot and build the damned northern beaches heavy rail as was originally planned. Then add another deck under the harbour bridge for the self indulgent car commuters to use the CE or decomission it and send the cars elsewhere and turn the deck into a piazza with views of the harbour.
I have previously advocated reclaiming the two eastern traffic lanes on the harbour bridge after the opening of the Western Harbour Tunnel for a Northern Beaches Railway, if feasible, which was Bradfield's original plan. Stub tunnels were constructed between North Sydney and Waverton Stations for that purpose and could still be utilised. The only impediment might be the feasibility of reinstating a rail bridge across the busy Warringah Freeway to connect North Sydney Station with the former Milsons Point tram platforms and the rail tracks to Wynyard Station and further south. The car park at Wynyard (platforms 1 & 2) isn't an issue as their lease is subject to a termination clause at the discretion of TfNSW.

The original alignment to the south from Wynyard platforms 1/2 to the Chalmers St underground platforms at Central is no longer possible because of subsequent property developments along the corridor, but it may still be feasible to divert to the western side of the CBD and connect with a City Relief Line from the west, allowing through running to the Northern Beaches. It would obviously have to be an extension of the Sydney Trains' network, but so what! It's not the end of the world. In view of the government's reluctance to branch metro lines, it's unlikely that another underground cross harbour rail link would be constructed when the former rail tracks could be reinstated on the bridge following construction of the WHT.

The WHT will have 3 traffic lanes in each direction, 2 of which will compensate for the loss of the eastern traffic lanes on the bridge. It doesn't preclude a continuing connection from the inbound residual lanes to the Cahill Expressway. It may be a bit more complex at the northern approaches to the bridge from Kirribilli, but not insurmountable. The WHT will offer an alternative route from the north to bypass the CBD, taking a lot of pressure off the Eastern Distributor and Western Distributor to access the M4 and M5, including Sydney Airport. A Northern Beaches Railway will also significantly reduce the need for buses to travel to the CBD across the bridge. There would be no need to construct another deck on the bridge for more traffic lanes.
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