#the last image really does me in like i'm looking at the dark blue sydney opera house elevation

[woollenpharaohs]

omg you're correct, this IS the website for infodumping. Ya'll asked for it, here it is, the Millau Viaduct, the tallest bridge in the world:

The above image is from when it was still in construction. The red posts have since been removed. I chose this photo because it gives a pretty good indication of why it is so tall.

Most tall bridges gain height in their cable-stay spans above deck, but this bad boy? It knocks the golden gate bridge right out of the park! At 336.4m in height (1,104 ft), its support pylons are greater in height than the cable-stay spans and that's because the bridge spans over a deep valley. Absolute mad lads... and the story behind why and how they even did this is such a trip.

I'm just paraphrasing Wikipedia's article but in the 1980s the traffic near a French town called Millau was getting super congested especially from people travelling through it from Paris to Spain in summer. The locals and government wanted to build a bypass which is all well and good when you're dealing with flat land but Millau is in the Tarn valley which is a mountainous area and densely forested. The Tarn is so significant it actually forms part of a UNESCO world heritage site. So building a bypass through the 'untouched' forest was not going to be an option.

In total four serious options were considered. Utimately the final route was chosen because it would have minimal impact on the environment (debatable), would not impact on existing or planned structures and was supported by the locals. Of the option chosen, the route could either take a low solution that descended into the valley, crossed the river with a bridge, then another viaduct and then a tunnel, or they could just straight up build a tall ass viaduct from two valley peaks above the river. The latter was more cost efficient and wouldn't interfere with the water table and so in 1991 the french government was like ok we've decided on how we want it done, now go forth, engineers, and bring our mad idea to life!

The government proceeded to run a design competition to select a team of architects and researchers to work on a technical solution for the route that the government had decided on. Due to the sheer insanity of their proposal, they got only 17 structural engineer offers and 38 architects. The government had to form an internal school of experts to help them decide which of the offers were suitable. The experts chose five basic proposals and the competition was re-launched to have the five chosen provide in-depth studies. The solution of a multi-span viaduct cable-stayed bridge was declared the best and so in 1998 tests commenced based on the winning design. The whole design process took about 7 years.

Obtaining a tender for the contractors was actually fairly easy despite the complexity of the design. That's because the government took the design stage to such a detailed level removing the onus on the contractor to nut out the fine details. This reportedly made the construction phase cheaper, though the whole construction cost up to 394 million euros.

I won't go into detail about how it was constructed, here's a short 3 min video explaining it and a 15 min video that more hilariously explains the whole insane concept. One thing that really stuck out to me was that nobody had ever constructed a bridge the way the Millau Viaduct had been designed so everything they did was run through mathematical algorithms multiple times. When they were to attach a span of the bridge deck to a pylon, they basically had to swing the enormous stretch of deck piece and hope that their mathematical calculations were correct for it to lodge into place first go because if it missed, the deck piece could slam against the pylon and could possibly fall into the river below. By sheer mathematical luck, the deck piece lodged exactly in place!

The engineering feat of this bridge is just astounding and it's so wild that the government were like ok we need to do this route this way now who wants to make it happen?? And like so few firms were willing to take it up, but by god did they make it work in the end.

Anyway, here are some extra fun facts. It is so tall that it required millions of surveillance devices to be installed all over the bridge to monitor even the slightest movement. This baby is more surveilled than the entire UK (an exaggeration, an joke). The above deck elements are reinforced and coated in weather-protected material to reduce impacts of being so high above natural ground level, and the aforementioned sensors also monitor the bridge's reactions to extreme weather. The initial speed limit over the bridge was 130km but they had to reduce it to 110km. I can't find anywhere that definitively says how long it takes to drive over it but it seems like 2-3 min? At which point you'd be above the height of the eiffel tower!

Lastly here is a comparative image of the height of the bridge in green to other notable bridges:

she tall.

@aromanticduck thank you for reblogging my initial post and letting me indulge in the wonder of the millau viaduct once again.

I was trying to tell two (2) seperate friends about the tallest bridge in the world and why I thought it was so cool but both times neither friend seemed particularly interested and I think that's just super funny for me personally because yeah why am I do fascinated by it sjjfjsjs