Building a highway inside a tunnel

[@MIKENORTHWEST]

Excellent! Clear, concise overview of key construction segments. Very interesting and informative! Thank you for taking the time to share this amazing information.

[@JZKnights]

Some tunnels are bigger than others

[@carolannaldrich5946]

This is amazing! Intelligent team work I had never imagined!

[@TheByard]

I worked as Senior Inspector of Works on the Kuala Lumper Smart Tunnel in Malaysia, designed as a flood relief tunnel but a contractor put in a bid for a dual use flood and double deck roadway tunnel. Escape routes were constructed outside the tunnel ring and included a stairway to connect the upper and lower road decks, watertight for use when the tunnel was closed to road traffic and used for flood relief. This method also left room for two lanes in each direction and an emergency walkway at the side. There were also watertight doors installed at the traffic entry and exit points. Road tolls will pay for the extra works required to make it a road tunnel. I'm told it takes about two days work to clean and replace damaged fixture after each flooding. Lighting etc. were chosen to be cheap and easy to replace, rather than very expensive units that still may get damaged. The tunnel has reduced driving times in the rush hour times and improved traffic flow. As with the Seattle tunnel the road decks were constructed during tunneling using mainly cast insitu systems.

[@christianjackson]

Very impressive.

[@walt1000]

Excellent presentation!

[@davefoc]

Well done video and the replies by wsdot have been very informative. Thank you. The tunnel opened for traffic on February 4, 2019.

[@ScottDLR]

It's open now and after just a few months, it's obviously too small. Brilliant work WSDOT.

[@Daren_PNW]

Nice presentation! Curious why the corbels appear vertical/horizontal and not perpendicular to the segments for even strength?

[@wsdot]

The shape and placement of the corbels is determined by the curved exterior of the tunnel. This rendering of the completed tunnel shows how they support the walls and road deck: www.flickr.com/photos/wsdot/sets/72157631528692308/

[@JasonJohnson]

Very interesting.

[@zyxwvutsrqponmlkh]

Epoxy covered rebar is proving to actually be worse than bare, hot dip galvanized seems to be the best (after basalt, which has limitations and is expensive).

[@jimstevenson2875]

Why does the upper roadway have walls? Why can't they just be the tunnel walls? Anyone know?

[@wsdot]

The walls on the west side of the upper roadway protect equipment and utilities in electrical rooms adjacent to the roadway. The walls on the east side of the roadway isolate the emergency ventilation space, which will be used to remove smoke and fumes from the tunnel as needed in the event of an emergency.

[@jimstevenson2875]

Very good - thank you

[@jakesnake4998]

get to see america built again

[@pierluc_cr]

What happens to the dirt removed by the TBR? Does it fall directly in truck? Is it store in the TBR?

[@wsdot]

Excavated soil was removed from the tunnel via a conveyor belt and loaded onto barges near the tunnel's south portal. The barges unloaded the soil at a disposal site on the west side of Puget Sound.

[@lottsalasagna431]

Isn’t this thing complete yet

[@wollinger]

Why not put a train line there too?

[@danielrose1392]

It is already a very big tunnel, it would require two tunnels. But yes, a light rail line would be great. Maybe shared with guided bus like the Adelaide O-Bus.

[@GANTZ100pts]

Don't give Sound Transit any ideas they might just try and do it. Then make us pay for it.

[@x1area51ii7]

incase of block or fire inside are they any emergency exit door in the tunnel for drivers?

[@wsdot]

Yes, there will be.

[@austinwalker7439]

8 jealous engineers from other states disliked this video

[@edwardlincoln5680]

Maybe they were scab carpenters or rod busters

[@russaman1000]

i just can’t wait till most of the construction projects are done in seattle. traffic is a nightmare and road/lane closures due to construction is not helping.

[@artsbest1]

Cool indeed but is it needed? How about public transportation instead? I mean the costs here with this project are enormous beyond words.

[@danielrose1392]

Irvin if you don't like using seats where someone else already sat on, how do you go to the movie theater? We have a good working public transportation system here where I live in Germany. Most vehicles are cleaned on a daily basis and I never saw stuff like needles or diapers there. Using public transportation for 15 years now.

[@ckywizard]

Public transportation here is trash. They would just raise fares and cut routes.

[@SuperBigblue19]

Daniel Rose--I am from Germany also. Germany ranks 55th in population density. The US ? 179 We also have greater distances to cover. Which makes public transit very time consuming with transfers & waiting. I can drive from my house to city center in less then 10 minutes. On a bus that would take at least a 10 min walk & 20min ride. I live 5.6 kilometers from downtown. Carpooling makes more sense here. We also do not have to be well off to afford a couple of vehicles and a freestanding home on property. I downsized to a home that would cost me 4x more money in Erlangen to biuld with the same layout. It also costs 28% less to own a car. 56% less in utilities. And we have 14% more disposable income. Germany & most of EU has to have & can have great public transport system. In the US it is only for those who live and work in high density areas- people who can't drive or to transport the poor.

[@mrbrainbob5320]

@@SuperBigblue19 whats the point of this who cares what Germany has.

[@SuperBigblue19]

Well obviously the state of WA does because their planners are developing projects based on EU density models. I am from Germany I don't live there. My post was a retort. If you can't keep up you should get rid of your narcissistic tag. Mrbrain, really? LOL!

[@surfie007]

Why dig a very wide tunnel to stack the roads, why not build two seperate tunnels like how most underground highways are built

[@wsdot]

We studied twin bored tunnels as a potential replacement option. The cost and time of boring two separate tunnels was considerably greater than building a single, large-diameter tunnel.

[@TestTest-fm2cu]

Can you guys come build some roads in Arizona, the workmanship out here is just disgusting and upsetting

[@corneliusdrvanderbilt822]

Bill Palmer Arizona neeedddsss no tunnels. It is a beautiful place. Let it be. Weather-wise, Seattle is shit place. Nope, I am not even an American.

[@SuperBigblue19]

Tunnel has no exits like the viaduct so you have to pay a toll to double back. This is a tourism & aesthetics project, not a commuter project. Unlike the Narrows and 520 bridges absurd tolls, they can't keep jacking up the crossing price without risking diversion. Right now drivers using the tunnel will be looking at a monthly hit to the wallet at between $40 to $80. And thats just in the beginning. If commuters divert like on 520 they will stick it to you even more.

[@GANTZ100pts]

SuperBigblue19 I can already see the traffic backup of people getting off the exit to avoid the toll.

[@bradleybruvva3021]

SuperBigblue19 If it’s anything like the narrows bridge toll in Tacoma, prices will continue to go up too. I remember when it was a couple bucks and now it’s like 6 dollars I think.

[@UceWayne253]

my sister is building this. get it sister love u moe

[@thegamechanger7157]

This is not my field but it's good.

[@sarahmeeker9512]

brilliant!

[@Explorersea]

exciting

[@KevinP32270]

epic.

[@hedunlap]

So, they are boring a tunnel to replace the double deck highway that may collapse in the event of seismic activity and then building a double deck highway inside the tunnel? The whole thing sounds silly. In the end you still have a double deck highway that may collapse in an earthquake. Only now they won't have to bury you when you die, you'll already be buried in a mass grave.

[@wsdot]

Structural engineers agree that tunnels can be one of the safest places to be during an earthquake. The SR 99 tunnel is being designed to withstand an earthquake that only happens ever 2,500 years on average (about a 9.0 magnitude) without collapsing.

[@GANTZ100pts]

hedunlap ironically tunnels are actually quite safe in an earthquake (providing there built properly) it's strange but true.

[@EVAUnit4A]

They built a single tunnel for a major highway right next to _and under_ waterfront property... within a major-threat earthquake zone. The alternative- a raised six-lane bridge to replace the old one- would have been far faster, cheaper and safer to both build and maintain. And keep this in mind: the Seattle residents who pushed so hard for this tunnel (so it wouldn't obstruct their _wonderful_ waterfront views!) are the exact same people who have successfully kept the rest of the city a half-century behind by shooting down the desperately-needed monorail expansion... which had been approved by state voters _four times._ #NotImpressed

[@mikegaskin5542]

Tunnels are way safer in an earthquake than raised structures on the surface. www.wsdot.wa.gov/Projects/Viaduct/Status/Blog/tunnels-and-earthquakes

[@alex-marquette]

um you obviously don't know much about engineering as this tunnel goes into the bedrock and energy waves from an earthquake pass right through the solid rock rather than having the energy transfer at the surface.

[@TheStig_TG]

Monirails are ass.

[@EVAUnit4A]

@@TheStig_TG Tell that to Europe and Japan.

[@TheStig_TG]

@@EVAUnit4A they take to much energy and trains are better, look it up on youtube monorails are not the future just a waste of money.

[@LK-pc4sq]

So who ever owned a condo...just saw its value increase at the expense of the taxpayer!

[@michaelwest720]

This is for the secrecy of shipping things that need a time schedule and part of prep for something strange. . what they say its for is probably a lie

[@Jimbogf]

wat

[@tonygumbrell22]

Ya sure, it's a conspiracy of the cyborgs.

[@ckywizard]

Building a highway no one wanted and installing tolls both in the tunnel and the struts above. You guys are crooks

[@michaelwest720]

Theres no way the public is gonna use this. Police wouldnt be able to get to anyone

[@wsdot]

There are shoulders that will allow emergency vehicles access.

[@ccmanize]

So you think the tunnel is just gonna sit empty while the streets above are in gridlock? LOL!