Austria is Digging a Tunnel Like No Other

I'm in a huge tunnel deep beneath Austria soon cars are going to zip through here without realizing that this space used to be solid rock and that's all made possible by this massive 250 tonne piece of Kent you won't find this on many construction sites it's a one-of-a-kind machine that was built especially for this project because this isn't how you'd normally dig if you've ever driven through a tunnel and wondered how it got there and why it isn't collapsing it's because of seriously impressive work like this Crews here are pushing day and night to carve a path that better connects this Austrian city with a massive new suspension bridge it's a challenging twisting and high stakes infrastructure scheme that's about to impact the lives of Millions now if you want to get around here in Lin's you could take a street car walk cycle or drive but there aren't many ways to get across the Danube so the city is building a brand new 305 meter suspension bridge but to build above the water you actually have to get there first and there's one little problem standing in the way these massive rocks so the team here in Linz is tunneling through them to connect the existing highways up to the new bridge they're basically trying to build a simple slip roads but inside a massive Cliff formed of solid rock and on both sides of the river now here at the b1m we kind of know a thing or two about how to build a tunnel time for another quick engineering 101. first choice for a tunnel these days is probably going to be a tunnel boring machine or TBM you know the ones they're massive tube-like machines that eat through Rock and then seal and line the newly formed tunnel with pre-fabricated concrete segments all in one go films are great because they're efficient and can travel underground without anyone living above really noticing like under ancient Woodlands all beneath the city that never sleeps but they're pretty expensive one of the nearly 1 000 ton TPMS used on London's Elizabeth line cost 10 million pounds so if you're splashing out for one of those bad boys you'd better be getting some serious mileage in and since they can be so big and we mean really big up to 15 meters wide and nearly 200 meters long big they're great for tunneling long stretches of a relatively straight path sounds like a no-brainer for a big infrastructure project right well yes but here's the site in Austria just 1600 meters of nothing but twists and turns through solid rock on the bank of a river so rather than trying to maneuver a giant TBM through its construction here went a little more like this this is the alternative and quite frankly much more fun way to build a tunnel granted it's not quite as a subtle but it gets the job done in incredibly simple terms you drill some holes in the Rock drop some explosives in Stand very far away hit a button called detonate clear out the rubble and repeat the whole thing until you have a tunnel when we say you we don't mean you please please employ Professional Engineers and construction teams the tunnels here in Linz were built using the new Austrian tunnel methods first the path was cleared using drill and blast with the debris taken away by boats along the river then angers and drainage points were installed concrete was sprayed onto the walls to create some initial stabilization and these giant Yellow waterproof sheets were installed but that's only half the battle once the tunnel's actually built the tear have to line it to create this nice smooth finish now you might think it'd be cheaper and easier just leave it as exposed craggy Rock and that would be the case but that would be pretty dangerous and create a long-term maintenance issue rocks could have fallen into the tunnel at any point over the tunnel's lifespan what you want is it looking nice and smooth by this that's where this thing comes in it's an absolutely enormous 250 ton piece of equipment developed by Perry formwork systems called a formwork carriage and it's been custom made for this site this is our fanberg against to concrete the whole tunnel the wars we used it for over 180 different sections here's how it works first all the parts of the machine are brought in by truck and assembled then workers prepare it by shrinking it down enough to move through the tunnel they'll remove the front bit called the stop end close the wings lower it down towards the ground and Roll It on through once it's inside the part of the tunnel that needs to be lined the wings will expand until they're very close to the existing Hard Rock concrete is then pumped up and through into the space between the formwork and the rock it molds into the smooth curved shape of the formwork and gives the tunnel its nice lining then it's a waiting game the concrete needs to cure overnight so the formwork stays in place until the morning when it can be safely shrunk back down and move forward to the next part of the tunnel even the slightest delay in the schedule during the day means the concrete won't be cured by the following morning which means the whole project gets thrown off no pressure then what's been the hardest part of this project from your perspective so we have added not a lot of space to work with that's a really tight curve inner side of the curve is shorter than the outside of the Curve so we had to adjust the framework to concrete on one side and longer section and on the other side this shoulder section now when it's at full length Perry's machine can work in 12 meter stretches but because there are such tight corners on this route sometimes the team needs to cut the machine in half and pour even smaller six meter slivers of concrete to create a curve in the tunnel now you might not notice when you're driving through but when you look closely you see the tunnel is actually formed smaller segments that are all fused together to help create that angle what's been the best thing about working on this project would it be most enjoyed every day brings a new problem or something new to think about [Music] when it completes millions of people will pass through this tunnel and the immense effort the way into building it will be taken for granted it shows Once Again The Power of construction to shape our world and the amount of innovation that's sometimes happening right beneath our feet this video was made possible by Perry formwork systems you can learn more about them and their massive machine at the link below there's also a chance to go even deeper into this tunnel over on the world's best construction podcast available right now wherever you get your podcasts and as always guys if you enjoyed this video and you want to get more from the definitive video channel for construction from the channel that takes you down Austrian tunnels hit that subscribe button [Music]

Channel: The B1M

Views: 718,720

Keywords: B1M, TheB1M, Construction, architecture, engineering, The B1M, Fred Mills, building, peri, tunnelling, austria, vienna, linz, travel, tourism, tunnel boring machine, tbm, drill and blast, formwork system, concrete, tunnel lining, bim, construction management, suspension bridge, cable stayed bridge

Id: pZHBpgt7kYQ

Length: 7min 54sec (474 seconds)

Published: Wed Jun 14 2023