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and used on almost every major suspension bridge since.
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Pieces just like that? It's incredible, isn't it?
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I mean, to think that is what's holding up...
4
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..well, us right now, this whole roadway, all the cars,
5
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all the trucks that keep thundering past.
6
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Yes.
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That's marvellous.
8
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So, the process of actually getting cables all the way across...
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It's called spinning because they use a wheel
10
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and the wheel is actually just a pulley.
11
00:29:07,810 --> 00:29:11,530
The curious method of spinning was invented in the 1840s
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by American engineer John Roebling
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It's lots and lots of pieces like that.
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It involves a pulley system that draws the wires across the span,
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pulling them off a huge drum at one end.
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00:29:25,850 --> 00:29:28,090
Bill and I are going to recreate the principal
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on a smaller scale, using string.
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00:29:31,010 --> 00:29:33,850
If you imagine a five-tonne reel of wire
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fastened into the anchorage.
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So this is me over on, let's say, the north...
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Over on the north bank.
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And then a spinning wheel pulling it.
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So I run this right across... Right across the river. ..across the estuary...
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And you'll see how fast this is unreeling. OK, yeah.
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Firstly, if one of these wires should snap,
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deep down into the concrete.
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Anyone who ever said engineering was dull and ugly
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has obviously never seen this.
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00:27:19,050 --> 00:27:20,890
It's absolutely beautiful.
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The 404 wires in each bunch are hooked onto giant bolts,
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each sunk 20m deep into the concrete wall.
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Each of these loops was carried across the Humber individually.
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There are nearly 15,000 lengths of wire in total.
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If you were to drive across the bridge in a small car,
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each of these wires would carry just about 30g of it.
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00:27:52,570 --> 00:27:57,210
All modern suspension bridge cables are made this way for two reasons.
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And then it gets looped there.
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there are still 14,947 remaining to hold the bridge up.
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The other reason is that dragging a 70cm thick, 5,000-tonne cable
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to the top of one tower
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across a 1.4km gap to the other tower,
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then down the far side would be impossible.
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00:28:20,490 --> 00:28:22,210
So, how was it actually done?
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To find out, I'm meeting with Bill Harvey,
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one of the engineers that worked on the job.
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Getting those cables up is just amazing.
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I mean, well, we're right under one of the main cables here.
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What you can't see from here is actually what's inside this sheet.
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To see how much the bridge moves,
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Even though four wires could be spun in just 15 minutes,
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it took 22 months to finish this part of the job.
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In October 1979,
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the last and most complicated major process could finally begin -
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erecting the 21,000-tonne roadway, the deck.
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00:31:20,250 --> 00:31:23,090
This, of course, is what it's all about.
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Everything else - the towers, the cables and the anchorages -
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all exist just to carry this ribbon of highway across the water.
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You might think that once the deck was in place
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the whole suspension bridge would be solid as a rock,
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but that's where you'd be wrong.
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Standing on that.
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even on a relatively calm day like today,
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just watch this coin.
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I've popped it down there,
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right up against the edge of this expansion joint,
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which connects the main bridge deck behind me
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and the side span there.
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Look at it go. You can see it's moving.
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That's a good 2 or 3cm there already,
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and it's the bridge deck where I am on this side that's moving.
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It's the gentle flex and sway of the bridge in the wind
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and with heavy traffic,
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It's going to take about 15 minutes to do a trip,
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And those bits get adjusted. Yeah.
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And then another loop is taken.
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00:29:57,330 --> 00:29:59,330
So actually in that one journey across,
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I've brought over two strands of wire.
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And, actually, there are two wires on the spinning wheel as well,
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so you've taken four and then you take another four.
80
00:30:09,530 --> 00:30:12,050
Wow, so this speeds things up hugely. Yeah.
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And then when you've done that 101 times -
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and there's 404 wires -
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you've got what's called a strand, and there are 37 strands up there.
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How long would that...?
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is where each of those bunches are anchor-pointed
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done thousands and thousands of times.
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To build up... Yeah.
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..this great big cable that we've got here now.
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And the guys who are working here just have to stand here
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and maybe stand in the middle of the river on the catwalk
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and catch the wires as they go past and anchor them.
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So, you'd have guys dotted along. All the way along.
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Just to kind of make sure and guide it and... Yeah.
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Make sure everything is going correctly? Yeah.
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And they'd be just stood up there, what, all day long? All day long.
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Some of the things the guys used to wear.
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the kind of all the infrastructure here...
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Everything was there. ..went up with it. Yeah, you even had...
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00:23:18,810 --> 00:23:20,770
Well, you can see there, this is the canteen.
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This is where the guys would have their lunch or whatever...
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You know, if it rained.
102
00:23:26,610 --> 00:23:28,850
So, what were the conditions like working on the bridge?
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I mean, you were up there in all weathers, I guess.
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If the weather was bad, you didn't go up.
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It was brutal up there, especially with the wind-chill factor.
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You could get down to -20, -30 up there.
107
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Jeez. It was, it was cold.
108
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And so as the towers grew,
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I know one guy who used to pinch his wife's tights
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because it would...to keep him warm in the winter.
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It was a standing joke, the idea was if you climbed the tower,
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it was 45 minutes and three cigarettes.
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(LAUGHS) To get from bottom to top.
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(LAUGHS)
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The North Tower was finished in May 1974.
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Next, they needed to repeat the slip forming process
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and build the South Tower, this time, in the river itself.
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But when engineers prepared to start work on the foundations,
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they discovered a serious problem with the sheet piles
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I'm meeting John Bailey,
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that slip forming is quicker, cheaper and safer
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than just about any other method of concrete construction.
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In the years since, it's become standard practice around the world
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for almost any kind of tower.
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If you look here on one of the Humber towers,
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you can see a series of horizontal lines
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where the concrete was poured a few inches at a time.
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It's almost like it's got a grain to it.
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Working constantly, it took just under six months
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to reach the full height,
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that's an average of 7.6cm an hour.
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surrounding the site.
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a local man who had a bird's eye view of this building revolution.
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John, you worked on top of the towers.
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What was it like up there?
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Initially, it was a little bit scary
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because you were going into the unknown.
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You'd never been up to that height before.
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When you get up to over 500 foot,
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then things look a little small from the top,
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so, it was, yeah...
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Your heart was in your mouth most of the time.
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(LAUGHS)
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than a 200,000 tonne slab of - well, you guessed it - concrete.
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The titanic weight of this structure
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and its partner on the opposite bank
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is all that stops the two cables from crashing into the river.
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But buried deep inside the anchorage is something totally unexpected.
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Wow.
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I mean, you know you're coming deep down
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because of all the ladders, they just keep going, but...
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..I don't think anything prepares you for this.
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Just listen to that echo. (VOICE ECHOES)
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Moo... (VOICE ECHOES)
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It's really nothing more
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In here, it's apparent
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that the suspension cables are not two enormous wires
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but actually thousands upon thousands of small wires,
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each just 5mm thick.
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Well, you can see
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right above me here is where one of those main cables,
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that runs the entire length of the bridge,
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comes in to the anchorage.
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And where it comes in, what was that great big, fat cable
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splays out into 37 different bunches of wires.
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And then these rows of orange blocks behind me
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they had this second tower topped out in nearly half the time,
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The design called for this man-made island
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for the south tower to sit on.
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But unexpectedly strong tidal currents ruined the sheet piles
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they put in to build it,
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helping cause a crippling two-year delay.
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Work on the rest of the bridge relied on both towers being up,
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but the sheet piles had to be reset
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and the foundations dried out.
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Project bosses were desperate to claw back some time.
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Amazingly, with the experience they gained on the first tower,
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and by working round-the-clock,
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it's almost like it's breathing in and out.
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increasing their average climb rate to almost 11cm per hour.
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Building the entire bridge was supposed to take just five years,
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but by 1976, four years into the project,
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only the towers were complete.
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The next major task was to lift the suspension cables
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up to the top of the towers,
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but unless they were securely fastened at each end,
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they would quickly come straight back down again.
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I'm descending into a tomb-like structure
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at the bridge's southern end called an anchorage.
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And that "the sections were swinging like seesaws,
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But during the complex process of assembling the deck,
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it was anything but stable.
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And in March 1980, disaster struck.
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At the north end of the bridge,
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one of the 40-tonne cranes broke loose
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and tumbled 70m down on to the incomplete roadway.
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The joints ripped apart,
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leaving two boxes dangling precariously.
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The Hull Daily Mail reported the dramatic accident,
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which happened just up here behind me.
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Saying, "A man was hanging on for his life."
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the more stable the bridge becomes.
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"hitting each other with the sound like a clap of thunder."
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It was a miracle nobody was killed
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and, amazingly, the damage done was minimal,
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but the whole incident was a very close call.
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What could have been a catastrophic disaster
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only set the timescale back by a few months.
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In December 1980,
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the final box was lifted into place,
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completing the span.
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The mighty Humber was bridged at last,
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but it came at quite a cost -
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This model is much more streamlined in shape,
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lifting it slightly.
216
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But gravity and tension in the cables pulled it back down
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and, rather like a playground swing, up the other way.
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The wind then amplified this movement,
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pushing it further in the same direction,
220
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then gravity and tension pulled it back even harder.
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The back-and-forth motion got stronger and higher with each swing
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until the bridge failed.
223
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Change the design of the bridge deck and watch this...
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It's the same fan, it's the same springs.
225
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Let's see what happens.
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£151 million in total.
227
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allowing the air to flow over it far more smoothly.
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Not much so far.
229
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But it does something else that's remarkably clever.
230
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It's the difference in lengths between the lower and upper deck
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that has the strange effect of lowering the air pressure
232
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under here compared to on top.
233
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Now, effectively, that forces the bridge deck downwards,
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pulling on the suspension cables.
235
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The bridge is bracing itself into the wind,
236
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and the windier it gets,
237
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he was the first toll-paying car to go over.
238
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I think I looked at my grandad the whole time and not her,
239
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but, yeah, it was...it was a really good day.
240
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I think now, you know, as years have gone by
241
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that it's very much a focal point of the city
242
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and in the people of Hull's, their hearts.
243
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Her Majesty made the first official crossing.
244
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Behind her, eager motorists queued up for their first turn.
245
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The toll charge - £1.
246
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Do you get a free toll pass? No. (LAUGHS)
247
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No, 'fraid not. Even my grandad didn't.
248
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Although he was the first person,
249
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And so, I did that and she was very pleasant.
250
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OK, very good. Yeah. Very good.
251
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The Humber Bridge is perhaps a bit forgotten about,
252
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slightly off the beaten track of Britain's motorway network,
253
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but we should remember that, here in the UK,
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we have a world record-breaking structure,
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what was for 17 years,
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the longest single-span suspension bridge on the planet.
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And it is a bridge to be proud of
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and to boast about
259
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because we made it and we made it here.
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Captions by Red Bee Media (c) SBS Australia 2019
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I'm meeting Rachel Stainforth,
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What's more, it had taken nine years instead of five
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and thanks to the rocketing inflation of the '70s,
264
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it was £81 million over budget.
265
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Some people criticised the bridge as a white elephant,
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a bridge from nowhere to nowhere,
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that should never really have been built.
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Despite all that,
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this structure was celebrated as a national achievement,
270
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the latest in a long line of groundbreaking British engineering landmarks.
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And no less a person than her Majesty the Queen opened the bridge
272
00:41:03,100 --> 00:41:06,100
on the 17th July 1981.
273
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At Tacoma, a strong wind pushed the bridge to one side,
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00:41:09,700 --> 00:41:12,780
who was there that day, aged just six.
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00:41:12,940 --> 00:41:16,620
So, the Humber Bridge has been here ever since you can remember, Rachel.
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It has. It's been a huge instrumental part of our family.
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00:41:20,460 --> 00:41:23,980
At the time, my grandad was chairman of the Humber Bridge Board
278
00:41:24,140 --> 00:41:29,500
and my nan was Lord Mayor of Hull, so, because I was in the family,
279
00:41:29,660 --> 00:41:32,140
I got asked to give the official bouquet to the Queen
280
00:41:32,300 --> 00:41:36,020
on the opening of the Humber Bridge, so I was six at the time, I think.
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And on the day, did it all go well?
282
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I did have a bit of stage fright at the beginning
283
00:41:40,820 --> 00:41:44,660
and so I had to have a nudge and said, you know, "Get on with it" sort of thing.
284
00:34:25,540 --> 00:34:28,340
began to swing in a way no-one intended.
285
00:33:43,020 --> 00:33:44,940
slowly drifting overhead.
286
00:33:48,420 --> 00:33:54,300
Lifting the 17,000-tonne steel road deck into position in 1979
287
00:33:54,460 --> 00:33:59,180
and keeping it there forever was going to be a serious challenge.
288
00:33:59,340 --> 00:34:02,420
That's because suspension bridges have an invisible enemy -
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the wind.
290
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To resist the force of gales,
291
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all of them are designed to allow sway,
292
00:34:08,540 --> 00:34:11,060
but one chilling lesson from history illustrates
293
00:34:11,220 --> 00:34:14,780
how this necessary flexibility can go badly wrong.
294
00:34:19,180 --> 00:34:22,860
In 1940, a suspension bridge across the Tacoma Narrows,
295
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just outside the US City of Seattle,
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00:33:40,300 --> 00:33:42,860
Like some kind of ridiculous space ship
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00:34:29,540 --> 00:34:31,100
Even before the bridge was finished,
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it would buck like a bronco in high winds.
299
00:34:34,380 --> 00:34:38,140
Construction workers nicknamed her Galloping Gertie.
300
00:34:38,300 --> 00:34:43,020
Eventually, this curious ripple turned into a full blown wave
301
00:34:43,180 --> 00:34:45,020
and just four months after it opened,
302
00:34:45,180 --> 00:34:47,860
the entire bridge ripped itself apart.
303
00:34:50,220 --> 00:34:52,540
There was something about the design of the roadway
304
00:34:52,700 --> 00:34:54,220
on the Tacoma Narrows Bridge
305
00:34:54,380 --> 00:34:57,340
that magnified the way it behaved in the wind.
306
00:34:57,500 --> 00:35:01,140
Something the designers on this bridge had to completely avoid,
307
00:35:01,300 --> 00:35:05,980
and the best way to see how they did it is by going down in here.
308
00:32:55,650 --> 00:32:58,010
and blows down much more easily.
309
00:32:24,930 --> 00:32:27,490
As cars and trucks thunder over the bridge,
310
00:32:27,650 --> 00:32:29,730
they cause the deck to jiggle a bit.
311
00:32:29,890 --> 00:32:33,530
But the bridge has to cope with a far greater force than traffic -
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00:32:33,690 --> 00:32:35,050
the wind.
313
00:32:35,210 --> 00:32:36,530
And when the wind picks up,
314
00:32:36,690 --> 00:32:40,050
movement in the structure is essential.
315
00:32:40,210 --> 00:32:44,570
Imagine a tree and a brick wall in a gale force wind.
316
00:32:44,730 --> 00:32:47,250
A tree bends and flexes,
317
00:32:47,410 --> 00:32:49,650
it's much more likely to remain standing.
318
00:32:49,810 --> 00:32:53,210
The brick wall acts like a huge sail,
319
00:32:53,370 --> 00:32:55,490
takes the full force of the wind
320
00:35:06,140 --> 00:35:08,500
I'm going inside the bridge deck...
321
00:32:58,170 --> 00:33:00,130
Likewise, with a suspension bridge,
322
00:33:00,290 --> 00:33:03,890
a bit of flex and sway is a good thing.
323
00:33:04,050 --> 00:33:05,850
But if you get your sums wrong,
324
00:33:06,010 --> 00:33:09,970
a bit of sway can turn into something much more extreme
325
00:33:10,130 --> 00:33:13,370
and the whole bridge could come crashing down.
326
00:33:21,300 --> 00:33:26,100
As slender and as elegant as it may seem from afar,
327
00:33:26,260 --> 00:33:30,100
it's not until you get right up under the bridge deck, like I am here now,
328
00:33:30,260 --> 00:33:33,820
that you get a true sense of the size
329
00:33:33,980 --> 00:33:36,340
and the strength of this thing.
330
00:33:38,580 --> 00:33:40,140
It's actually quite intimidating.
331
00:37:06,620 --> 00:37:09,700
This one is much squarer
332
00:36:24,940 --> 00:36:28,460
and it's the shape of that deck which ensures the Humber Bridge
333
00:36:28,620 --> 00:36:30,980
will never gallop like Gertie.
334
00:36:34,060 --> 00:36:36,300
Along the entire length of the bridge deck,
335
00:36:36,460 --> 00:36:39,460
it's flat here in the centre above and below me,
336
00:36:39,620 --> 00:36:42,380
and then it slopes away at the sides.
337
00:36:42,540 --> 00:36:46,100
You can see it much better on this model here.
338
00:36:46,260 --> 00:36:49,860
So underneath, it's shaped like a saucer,
339
00:36:50,020 --> 00:36:54,340
and over the top, it's shaped, well, like an upside down saucer.
340
00:36:55,660 --> 00:36:59,420
Compare that then to this model here of the bridge deck
341
00:36:59,580 --> 00:37:02,220
of the ill-fated Tacoma Narrows Bridge.
342
00:37:04,100 --> 00:37:06,460
You can see they're very different.
343
00:36:22,660 --> 00:36:24,780
to form a continuous deck,
344
00:37:09,860 --> 00:37:13,940
and it's got these solid side barriers all the way along.
345
00:37:15,900 --> 00:37:18,580
So, let's see what happens to this with a little bit of wind.
346
00:37:25,500 --> 00:37:29,620
Now, you might expect the bridge deck just to be pushed away by the fan
347
00:37:29,780 --> 00:37:32,660
and kind of stay there until I turn it off,
348
00:37:32,820 --> 00:37:34,500
but give it a sec.
349
00:37:34,660 --> 00:37:36,620
It starts to sway gradually,
350
00:37:36,780 --> 00:37:38,380
but it doesn't take long
351
00:37:38,540 --> 00:37:42,420
for the Tacoma model to waggle erratically.
352
00:37:42,580 --> 00:37:43,980
But look at that.
353
00:37:44,140 --> 00:37:47,980
It's going absolutely berserk, it's osculating back and forth.
354
00:37:50,380 --> 00:37:52,620
It's a phenomena called flutter.
355
00:35:46,740 --> 00:35:49,420
and then another kilometre all the way down
356
00:35:09,940 --> 00:35:11,100
(LAUGHS)
357
00:35:12,700 --> 00:35:14,420
(LAUGHS)
358
00:35:16,900 --> 00:35:18,940
So, you leave the day light behind,
359
00:35:19,100 --> 00:35:23,180
coming right down into this huge, cavernous void.
360
00:35:23,340 --> 00:35:24,820
(LAUGHS) (LOUD RUMBLING OVERHEAD)
361
00:35:24,980 --> 00:35:28,220
And it's noisy too with the cars and trucks going overhead.
362
00:35:28,380 --> 00:35:31,580
They're literally right overhead, just there.
363
00:35:32,980 --> 00:35:35,940
This is the middle of the bridge deck.
364
00:35:36,100 --> 00:35:40,940
It's a series of these vast, hollow, steel boxes,
365
00:35:41,100 --> 00:35:43,860
which continue for a kilometre in that direction,
366
00:35:44,020 --> 00:35:46,580
along to the north side of the river,
367
00:21:58,690 --> 00:22:00,410
The Humber Bridge towers proved
368
00:35:49,580 --> 00:35:52,980
back in that direction, too, over to the south bank.
369
00:35:53,140 --> 00:35:54,940
(LAUGHS)
370
00:35:56,180 --> 00:35:58,020
It's really odd down here.
371
00:36:01,140 --> 00:36:04,660
Each one of these boxes was pre-fabricated on land,
372
00:36:04,820 --> 00:36:07,820
but getting them into place was no easy feat.
373
00:36:07,980 --> 00:36:09,820
Starting at the dead centre of the bridge,
374
00:36:09,980 --> 00:36:11,300
they were floated into position,
375
00:36:11,460 --> 00:36:14,780
then hoisted one by one with huge cranes,
376
00:36:14,940 --> 00:36:17,940
which themselves hung off the suspension cables.
377
00:36:19,940 --> 00:36:22,500
Each box was then welded to its neighbours
378
00:07:42,620 --> 00:07:44,860
that the bridge really got built.
379
00:07:05,220 --> 00:07:09,380
it was the longest single-span suspension bridge ever built,
380
00:07:09,540 --> 00:07:13,340
with a road deck 2.2km long.
381
00:07:13,500 --> 00:07:16,780
This new roadway connected communities
382
00:07:16,940 --> 00:07:18,500
on opposite banks of the estuary
383
00:07:18,660 --> 00:07:21,380
that used to be 70 miles apart by road.
384
00:07:21,540 --> 00:07:25,100
Overnight, they became brand-new neighbours.
385
00:07:25,260 --> 00:07:27,380
But more than that,
386
00:07:27,540 --> 00:07:30,820
this record-breaking bridge formed the promise of a new future
387
00:07:30,980 --> 00:07:32,300
for this part of Britain.
388
00:07:32,460 --> 00:07:36,100
It would spur the creation of a new industrial hub for the nation.
389
00:07:39,260 --> 00:07:42,460
But it wasn't quite for such public-spirited reasons
390
00:07:02,020 --> 00:07:05,060
When the Humber Bridge opened in 1981,
391
00:07:45,020 --> 00:07:47,940
It's widely held that it was, in fact, the result
392
00:07:48,100 --> 00:07:52,340
of some rather more calculated political game-playing.
393
00:07:54,060 --> 00:07:55,580
Back in the 1960s,
394
00:07:55,740 --> 00:07:58,940
the folk of the Humber towns had already spent decades
395
00:07:59,100 --> 00:08:00,860
campaigning for a new bridge.
396
00:08:01,020 --> 00:08:05,340
Theirs was the only estuary in Britain that didn't have one.
397
00:08:05,500 --> 00:08:08,260
But a bridge that could span this expanse of water
398
00:08:08,420 --> 00:08:10,620
would not only have to be extremely long,
399
00:08:10,780 --> 00:08:13,380
but also very tall.
400
00:08:13,540 --> 00:08:16,060
There are four major ports on the Humber
401
00:08:16,220 --> 00:08:21,180
that carry a hefty 13% of the UK's seaborne trade between them.
402
00:06:15,860 --> 00:06:19,180
The Tattershall Castle put in 39 years service on the Humber,
403
00:05:41,500 --> 00:05:43,660
It was built in the 1930s.
404
00:05:43,820 --> 00:05:46,700
If you look you can see all these beautiful brass fittings,
405
00:05:46,860 --> 00:05:50,260
this great big crank shaft and connecting rods.
406
00:05:51,500 --> 00:05:54,140
And down here, you can see where the spindles would be attached,
407
00:05:54,300 --> 00:05:56,100
and there would be another one on the other side,
408
00:05:56,260 --> 00:05:59,700
and they'd head straight out to drive the great big paddles
409
00:05:59,860 --> 00:06:01,980
on each side on the outside of the hull.
410
00:06:02,140 --> 00:06:05,460
Sadly, the paddles have long since been removed,
411
00:06:05,620 --> 00:06:08,660
but you can see the deck extensions that once sat above them.
412
00:06:08,820 --> 00:06:12,700
These images show the steamer in its final days
413
00:06:12,860 --> 00:06:15,700
under the ownership of British Rail.
414
00:08:22,220 --> 00:08:26,820
With 4,500-tonne cargo ships regularly passing the bridge,
415
00:06:19,340 --> 00:06:22,700
before being brought to London in 1975.
416
00:06:22,860 --> 00:06:25,500
But the fact that this old paddle steamer should end up
417
00:06:25,660 --> 00:06:28,940
here on the River Thames is oddly fitting.
418
00:06:29,100 --> 00:06:30,620
You see, it was right there,
419
00:06:30,780 --> 00:06:32,460
in the Houses of Parliament behind me,
420
00:06:32,620 --> 00:06:35,460
that this ferry lost its job on the Humber.
421
00:06:35,620 --> 00:06:38,940
It was a casualty of a fierce political struggle
422
00:06:39,100 --> 00:06:41,380
that saw the voters of Hull being offered
423
00:06:41,540 --> 00:06:45,100
what was seen as an extraordinary election bribe -
424
00:06:45,260 --> 00:06:46,580
a bridge.
425
00:06:46,740 --> 00:06:49,820
A bridge that was set to be the longest in the world.
426
00:10:32,100 --> 00:10:36,700
Mrs Castle stood up to give a speech to 200 people
427
00:09:53,260 --> 00:09:55,420
This man died.
428
00:09:55,580 --> 00:09:58,100
Henry Solomons MP.
429
00:10:00,780 --> 00:10:03,780
Harold Wilson's Labour Government was made highly vulnerable
430
00:10:03,940 --> 00:10:05,700
by the death of Mr Solomons.
431
00:10:05,860 --> 00:10:08,700
A by-election for his Hull North seat was set
432
00:10:08,860 --> 00:10:12,380
for the 27th of January, 1966.
433
00:10:12,540 --> 00:10:19,180
If Labour lost, Wilson would be left with a majority of just one MP.
434
00:10:19,340 --> 00:10:22,220
For Labour, a win was crucial.
435
00:10:22,380 --> 00:10:25,660
Wilson dispatched his most experienced political operators
436
00:10:25,820 --> 00:10:27,140
to win over the voters,
437
00:10:27,300 --> 00:10:31,940
including the transport minister, Barbara Castle.
438
00:09:48,940 --> 00:09:52,180
all of a sudden, worth it to the Government.
439
00:10:36,860 --> 00:10:39,740
crammed into a local school hall.
440
00:10:39,900 --> 00:10:44,180
Everyone expected some kind of road improvement carrot to be dangled,
441
00:10:44,340 --> 00:10:49,340
but then she came out with six words that nobody anticipated -
442
00:10:49,500 --> 00:10:52,300
"You will have your Humber Bridge".
443
00:10:52,460 --> 00:10:56,820
Nine days later, the people of Hull went to the polls,
444
00:10:56,980 --> 00:11:00,140
and here at the city hall, the votes were counted.
445
00:11:01,620 --> 00:11:04,780
MAN: Joseph Kevin McNamara, Labour, 24,000...
446
00:11:04,940 --> 00:11:06,980
(CHEERING)
447
00:11:07,140 --> 00:11:09,500
It was a victory for Labour.
448
00:11:09,660 --> 00:11:12,700
The bridge would finally be built.
449
00:11:12,860 --> 00:11:16,940
But six years later, when Wilson was voted out of office,
450
00:09:06,900 --> 00:09:10,540
A suspension bridge could cross the water in one giant leap,
451
00:08:26,980 --> 00:08:30,900
the deck had to be high enough to allow them to flow underneath.
452
00:08:31,060 --> 00:08:33,980
But the design also had to take into account
453
00:08:34,140 --> 00:08:36,780
what goes on under the water.
454
00:08:37,940 --> 00:08:40,740
The Humber Estuary has a very soft bed,
455
00:08:40,900 --> 00:08:44,980
with deep channels and shallow banks that can shift over time.
456
00:08:46,460 --> 00:08:48,740
As those deep channels move,
457
00:08:48,900 --> 00:08:51,220
the shipping lanes need to move with them.
458
00:08:51,380 --> 00:08:54,940
Most kinds of bridge able to span a river this size,
459
00:08:55,100 --> 00:08:57,500
require a whole series of supports,
460
00:08:57,660 --> 00:09:02,460
leaving only narrow gaps for shipping that could easily silt up.
461
00:09:02,620 --> 00:09:06,740
But there's one type of design that needs just two towers.
462
00:05:39,980 --> 00:05:41,340
Now, this is the engine room.
463
00:09:10,700 --> 00:09:13,940
allowing ships to follow the channels as they change.
464
00:09:15,780 --> 00:09:19,060
So to keep the full width of the estuary open,
465
00:09:19,220 --> 00:09:21,820
this bridge had to be a suspension bridge.
466
00:09:21,980 --> 00:09:25,260
And with the banks more than 2km apart,
467
00:09:25,420 --> 00:09:29,260
it would be the longest single-span ever.
468
00:09:32,380 --> 00:09:33,780
Despite their advantages,
469
00:09:33,940 --> 00:09:38,780
suspension bridges are complicated and, therefore, costly to build.
470
00:09:38,940 --> 00:09:42,780
No-one seemed willing to spend the kind of money needed.
471
00:09:43,940 --> 00:09:46,100
Then something happened
472
00:09:46,260 --> 00:09:48,780
that would make the expense of such a construction,
473
00:02:14,860 --> 00:02:17,940
they're about 70cm thick.
474
00:01:34,060 --> 00:01:36,180
It's so high up.
475
00:01:36,340 --> 00:01:40,420
It's nothing apart from these two cables which disappear off.
476
00:01:40,580 --> 00:01:42,020
(LAUGHS)
477
00:01:42,180 --> 00:01:44,260
This is the Humber Bridge.
478
00:01:44,420 --> 00:01:49,180
Its length from end to end is more than 2km,
479
00:01:49,340 --> 00:01:52,300
and between the two gigantic towers,
480
00:01:52,460 --> 00:01:56,020
stretches one of the greatest engineering feats in history.
481
00:01:57,700 --> 00:02:03,420
The suspended central span is 1,410m long,
482
00:02:03,580 --> 00:02:06,340
and when it opened in 1981,
483
00:02:06,500 --> 00:02:10,260
it was the biggest suspension bridge on the planet.
484
00:02:11,580 --> 00:02:14,700
Just look at these two enormous cables,
485
00:01:30,860 --> 00:01:32,700
This is something special.
486
00:02:18,100 --> 00:02:21,180
Each of them weighs over 5,000 tonnes.
487
00:02:24,460 --> 00:02:26,260
Then there's the towers,
488
00:02:26,420 --> 00:02:28,220
the one on I'm stood on here on the north side,
489
00:02:28,380 --> 00:02:31,180
and the one way off in the distance.
490
00:02:31,340 --> 00:02:33,460
These things are so tall,
491
00:02:33,620 --> 00:02:37,020
they're actually further apart at the top than they are at the bottom.
492
00:02:37,180 --> 00:02:38,500
And you know why?
493
00:02:38,660 --> 00:02:40,940
Because of the curvature of the Earth,
494
00:02:41,100 --> 00:02:43,340
that's the scale we're talking about here.
495
00:02:43,500 --> 00:02:45,340
The whole thing is epic.
496
00:02:51,900 --> 00:02:54,020
For nearly two decades,
497
00:00:40,660 --> 00:00:42,540
Stopping traffic.
498
00:00:05,020 --> 00:00:06,940
spanning our most dramatic landscapes,
499
00:00:07,100 --> 00:00:10,500
have not only linked our island but made it great.
500
00:00:10,660 --> 00:00:13,660
These are the bridges that are known around the world,
501
00:00:13,820 --> 00:00:17,220
built by visionaries like Stevenson and Brunel
502
00:00:17,380 --> 00:00:19,620
who are famous even today.
503
00:00:21,020 --> 00:00:22,820
Look at this!
504
00:00:22,980 --> 00:00:25,860
From the banks of the Tyne to the mighty Thames,
505
00:00:26,020 --> 00:00:29,460
from the Firth of Forth to the Menai Strait...
506
00:00:30,700 --> 00:00:35,140
..I'm on a journey to discover how those great bridges were built...
507
00:00:35,300 --> 00:00:36,620
Here we go.
508
00:00:36,780 --> 00:00:40,500
..and the sweat and sacrifice that went into their constructions.
509
00:02:54,180 --> 00:02:57,300
this colossal edifice reigned supreme.
510
00:00:42,700 --> 00:00:46,660
I'll uncover the huge egos, flawed geniuses and jealous rivalries
511
00:00:46,820 --> 00:00:48,740
behind their creation.
512
00:00:48,900 --> 00:00:51,780
It's as if he'd been airbrushed from the whole story.
513
00:00:53,980 --> 00:00:56,900
These are Britain's Greatest Bridges.
514
00:01:02,620 --> 00:01:04,780
On the eastern fringes of the British Isles,
515
00:01:04,940 --> 00:01:08,860
there's an extraordinary structure that is somewhat forgotten.
516
00:01:10,780 --> 00:01:15,620
It's a record-breaking structure that changed engineering forever,
517
00:01:15,780 --> 00:01:18,940
and we've been given special permission to explore it,
518
00:01:19,100 --> 00:01:21,220
from bottom to top.
519
00:01:26,660 --> 00:01:29,500
Oh, wow! Oh, my goodness!
520
00:04:57,340 --> 00:05:01,580
The paddles on the steamer allowed them to navigate very shallow waters,
521
00:04:19,460 --> 00:04:21,860
This is Yorkshire.
522
00:04:22,020 --> 00:04:26,500
Across the other side, away over the expanse of the bridge,
523
00:04:26,660 --> 00:04:28,340
is the south side of the estuary.
524
00:04:28,500 --> 00:04:30,260
That's North Lincolnshire.
525
00:04:30,380 --> 00:04:33,820
And if you look out east, you've got the town of Grimsby,
526
00:04:33,980 --> 00:04:36,860
and further east, you're into the North Sea.
527
00:04:40,700 --> 00:04:42,180
Before the bridge was built,
528
00:04:42,340 --> 00:04:44,860
driving from one side of the Humber to the other
529
00:04:45,020 --> 00:04:49,180
involved a 70-mile road journey that could take two hours or more.
530
00:04:49,340 --> 00:04:51,980
The only way to cross quicker,
531
00:04:52,140 --> 00:04:55,820
was to ride on Britain's answer to a Mississippi paddle steamer.
532
00:04:15,620 --> 00:04:19,300
Off in the distance there, the city of Kingston upon Hull.
533
00:05:01,740 --> 00:05:05,380
but the silty Humber was so shallow in places,
534
00:05:05,540 --> 00:05:07,900
the ferry still ran aground from time to time,
535
00:05:08,060 --> 00:05:12,820
stranded in the middle of the estuary until the tide changed.
536
00:05:14,020 --> 00:05:17,060
Amazingly, decades since it was put of a job on the Humber
537
00:05:17,220 --> 00:05:18,540
when the bridge opened,
538
00:05:18,700 --> 00:05:21,660
you can still hop aboard one of the paddle ferries today,
539
00:05:21,820 --> 00:05:24,500
here on the banks of the River Thames in London.
540
00:05:25,980 --> 00:05:29,340
Now, permanently moored, and used as a popular bar,
541
00:05:29,500 --> 00:05:32,180
the Tattershall Castle, as this vessel is known,
542
00:05:32,340 --> 00:05:34,700
is in remarkable condition.
543
00:05:34,860 --> 00:05:38,660
Stepping aboard is like walking into a long forgotten world.
544
00:03:45,660 --> 00:03:47,500
As with most great bridges,
545
00:02:57,460 --> 00:03:01,460
The longest span of any suspension bridge in the world.
546
00:03:02,780 --> 00:03:05,020
For many, including me,
547
00:03:05,180 --> 00:03:08,860
the Humber Bridge is one of the most beautiful bridges ever built.
548
00:03:09,020 --> 00:03:13,660
There's an understated simplicity that I just love.
549
00:03:13,820 --> 00:03:18,380
The way it disguises thousands of tonnes of concrete and steel,
550
00:03:18,540 --> 00:03:21,900
like a feather floating effortlessly across the water.
551
00:03:26,460 --> 00:03:30,500
But building this record-breaking bridge was far from effortless.
552
00:03:30,660 --> 00:03:32,820
It was a severe technical challenge,
553
00:03:32,980 --> 00:03:36,860
born out of an extraordinary political power struggle.
554
00:03:37,020 --> 00:03:42,140
So just what did it take to build the longest bridge in the world
555
00:03:42,300 --> 00:03:44,300
right here in Britain?
556
00:11:17,100 --> 00:11:19,500
there was still no bridge.
557
00:03:47,660 --> 00:03:50,780
the story of this one begins with a stretch of water
558
00:03:50,940 --> 00:03:53,820
that many people thought unbridgeable -
559
00:03:53,980 --> 00:03:55,820
the wide Humber Estuary.
560
00:03:56,860 --> 00:03:59,580
Formed by the combination of two great rivers,
561
00:03:59,740 --> 00:04:01,300
the Ouse and the Trent,
562
00:04:01,460 --> 00:04:03,820
and almost 60km long,
563
00:04:03,980 --> 00:04:09,020
this tidal inlet divides a major industrial region in half.
564
00:04:09,180 --> 00:04:11,140
Let's have a little look at the lie of the land.
565
00:04:11,300 --> 00:04:12,860
So I've come up the north tower,
566
00:04:13,020 --> 00:04:15,460
so this is the north side of the estuary.
567
00:18:38,420 --> 00:18:41,020
totally changed its behaviour.
568
00:18:10,700 --> 00:18:12,020
like when a heavy lorry
569
00:18:12,180 --> 00:18:13,540
crosses a suspension bridge,
570
00:18:13,700 --> 00:18:15,580
could cause it to crack apart.
571
00:18:17,180 --> 00:18:18,700
Monier found this same problem
572
00:18:18,860 --> 00:18:22,060
when he tried to drag his orange pots around the garden,
573
00:18:22,220 --> 00:18:25,340
until he made a simple change to their design.
574
00:18:25,500 --> 00:18:26,860
Monier discovered
575
00:18:27,020 --> 00:18:29,940
that if he put iron rods into the concrete as it set,
576
00:18:30,100 --> 00:18:33,460
when it hardened, it was much stronger.
577
00:18:33,620 --> 00:18:35,100
That simple addition -
578
00:18:35,260 --> 00:18:38,260
adding metal rods to create reinforced concrete -
579
00:18:09,180 --> 00:18:10,540
So any sideways pull,
580
00:18:41,180 --> 00:18:42,540
This new form of concrete
581
00:18:42,700 --> 00:18:44,020
is as strong in tension
582
00:18:44,180 --> 00:18:45,500
as it is in compression,
583
00:18:45,660 --> 00:18:46,980
making it perfect
584
00:18:47,140 --> 00:18:49,820
for almost any kind of structure.
585
00:18:49,980 --> 00:18:51,900
By the middle of the 20th century,
586
00:18:52,060 --> 00:18:55,140
architects and engineers were finding amazing new ways
587
00:18:55,300 --> 00:18:57,300
to exploit its properties.
588
00:18:57,460 --> 00:19:01,500
The engineers at Freeman Fox wanted to take that one step further.
589
00:19:01,660 --> 00:19:05,180
They knew using reinforced concrete instead of steel could save
590
00:19:05,340 --> 00:19:08,940
months of construction time and millions of pounds
591
00:17:34,980 --> 00:17:37,300
The Humber Bridge is still standing today,
592
00:16:53,180 --> 00:16:56,500
They used it on the world-famous Pantheon in Rome.
593
00:16:56,660 --> 00:16:59,980
Its dome is one of the biggest in the world made of concrete,
594
00:17:00,140 --> 00:17:04,380
and it's been standing for nearly 2,000 years.
595
00:17:04,540 --> 00:17:09,740
But suspension bridge towers are subject to quite different and far greater forces
596
00:17:09,900 --> 00:17:11,700
than most buildings.
597
00:17:12,900 --> 00:17:15,180
The thing was, up until that point,
598
00:17:15,340 --> 00:17:19,780
suspension bridge towers had almost always been made out of steel,
599
00:17:19,940 --> 00:17:23,420
so the bridge designers had to be absolutely certain
600
00:17:23,580 --> 00:17:28,060
that a huge concrete tower would be equivalent in strength,
601
00:17:28,220 --> 00:17:32,900
and the reason they could be was all to do with these.
602
00:17:33,060 --> 00:17:34,820
Oranges.
603
00:19:09,100 --> 00:19:13,700
if they could find a way to get it into place quickly and safely.
604
00:17:37,460 --> 00:17:40,700
thanks to a French gardener called Joseph Monier.
605
00:17:40,860 --> 00:17:42,820
It was the 1860s
606
00:17:42,980 --> 00:17:46,300
and Monier worked at the historic Royal Palace in Paris
607
00:17:46,460 --> 00:17:50,260
where one of his jobs was to look after the exotic citrus plants.
608
00:17:50,420 --> 00:17:53,860
Every summer, he'd have to move them from inside their glasshouse
609
00:17:54,020 --> 00:17:55,620
to the gardens outside,
610
00:17:55,780 --> 00:17:58,740
but the concrete pots they were in kept breaking.
611
00:18:00,940 --> 00:18:03,620
The problem is that whilst concrete is very strong
612
00:18:03,780 --> 00:18:05,500
under the force of compression,
613
00:18:05,660 --> 00:18:09,020
it's very weak under the force of tension.
614
00:21:18,570 --> 00:21:21,450
called the Landmark.
615
00:20:36,410 --> 00:20:41,210
and remained the longest unsupported roadway until 1998.
616
00:20:43,210 --> 00:20:46,730
One of the challenges facing the bridge's designers at Freeman Fox
617
00:20:46,890 --> 00:20:50,930
was the massive towers that such a structure needed.
618
00:20:51,090 --> 00:20:54,530
They would be some of the tallest ever built from concrete,
619
00:20:54,690 --> 00:20:58,370
but most existing methods for pouring the concrete just weren't suitable...
620
00:21:00,050 --> 00:21:03,770
..so they took a punt on a novel technique.
621
00:21:03,930 --> 00:21:06,930
The technique enabled tall structures to be built quicker
622
00:21:07,090 --> 00:21:09,330
and more efficiently than ever before.
623
00:21:09,490 --> 00:21:12,090
It was called slip forming.
624
00:21:12,250 --> 00:21:14,970
Slip forming gained popularity in the 1960s
625
00:21:15,130 --> 00:21:18,410
after being used to build a 31-storey tower in Las Vegas
626
00:20:32,610 --> 00:20:36,250
It used new materials, and groundbreaking methods
627
00:21:21,610 --> 00:21:25,290
Building a giant, 155m-high mould,
628
00:21:25,450 --> 00:21:27,810
then pouring concrete from the very top
629
00:21:27,970 --> 00:21:29,530
would be technically challenging,
630
00:21:29,690 --> 00:21:33,530
really costly, and take far too long.
631
00:21:33,690 --> 00:21:38,610
But slip forming needs only a small mould, about 6m high.
632
00:21:38,770 --> 00:21:41,930
As the lower parts of the new tower dry and harden,
633
00:21:42,090 --> 00:21:46,330
the mould is shifted, or slipped, up a few centimetres on jacks.
634
00:21:46,490 --> 00:21:49,850
All the while the concrete is poured without interruption.
635
00:21:50,010 --> 00:21:52,090
The mould moves continuously upwards,
636
00:21:52,250 --> 00:21:56,170
leaving behind a single, solid structure.
637
00:21:56,330 --> 00:21:58,530
The technique worked impressively.
638
00:19:48,180 --> 00:19:50,260
and pour concrete in from the top.
639
00:19:13,860 --> 00:19:16,500
Because even if the concrete itself was up to the job,
640
00:19:16,660 --> 00:19:20,140
most methods of casting it weren't.
641
00:19:20,300 --> 00:19:22,620
A typical way to make a concrete structure was
642
00:19:22,780 --> 00:19:24,940
to pre-cast it into small pieces
643
00:19:25,100 --> 00:19:28,580
and hoist each one into position by crane,
644
00:19:28,740 --> 00:19:31,340
one by one.
645
00:19:31,500 --> 00:19:33,220
But that was out of the question
646
00:19:33,380 --> 00:19:36,220
with the kind of heights they were talking about here.
647
00:19:37,500 --> 00:19:40,140
Hey! (CHUCKLES)
648
00:19:40,300 --> 00:19:44,300
Another option was to cast the entire structure in-situ,
649
00:19:44,460 --> 00:19:48,020
but you can't build a 155m-high mould
650
00:16:49,300 --> 00:16:53,020
The Romans were the first large-scale users of concrete.
651
00:19:50,420 --> 00:19:51,820
So, that's when they turned
652
00:19:51,980 --> 00:19:54,940
to another fashionable, new building technique.
653
00:19:55,100 --> 00:19:58,700
It was called slip forming and it had proved successful
654
00:19:58,860 --> 00:20:02,540
in building a futuristic hotel and casino in Las Vegas.
655
00:20:02,700 --> 00:20:06,100
But could Freeman Fox transplant this technology
656
00:20:06,260 --> 00:20:10,580
from the parched Nevada desert to the watery world of the Humber?
657
00:20:10,740 --> 00:20:13,100
It was a gamble they just had to take.
658
00:20:23,330 --> 00:20:25,410
The Humber Suspension Bridge,
659
00:20:25,570 --> 00:20:28,890
with its world record-breaking span across the Humber Estuary,
660
00:20:29,050 --> 00:20:32,450
it's a triumph of 1970s engineering.
661
00:13:12,420 --> 00:13:14,980
And what I've created here is much more of a...
662
00:12:28,220 --> 00:12:32,060
The answer is to start where every suspension bridge must,
663
00:12:32,220 --> 00:12:35,900
with two enormous holes in the ground.
664
00:12:36,060 --> 00:12:39,740
These holes will form the foundations for the towers.
665
00:12:39,900 --> 00:12:43,140
The towers will then be used to hold up the suspension cables,
666
00:12:43,300 --> 00:12:46,940
and from those cables, the road deck will be suspended
667
00:12:47,100 --> 00:12:49,460
from a series of smaller vertical cables
668
00:12:49,620 --> 00:12:51,980
called hangers.
669
00:12:52,140 --> 00:12:54,340
But it all starts with the holes,
670
00:12:54,500 --> 00:12:58,180
and digging those is not as easy as it seems.
671
00:13:00,220 --> 00:13:02,620
If you've ever dug a hole on a beach before,
672
00:13:02,780 --> 00:13:06,140
you know it doesn't take long before it starts filling up with water.
673
00:12:25,540 --> 00:12:28,060
with a 2km road hanging off it?
674
00:13:15,140 --> 00:13:17,780
..murky pond than any kind of basis
675
00:13:17,940 --> 00:13:21,740
for a 155m suspension bridge tower.
676
00:13:26,740 --> 00:13:31,820
The way to make a dry hole on a wet beach is to use sheet piles.
677
00:13:31,980 --> 00:13:35,740
These long interlocking strips of steel are literally hammered
678
00:13:35,900 --> 00:13:39,820
into the ground to create a curtain of metal.
679
00:13:39,980 --> 00:13:43,300
On the Dutch River, one of the Humber's tributaries,
680
00:13:43,460 --> 00:13:47,980
Phil Boyes of the Environment Agency is driving piles into the riverbed
681
00:13:48,140 --> 00:13:50,180
as a flood defence.
682
00:13:50,340 --> 00:13:54,420
As one sheet goes down right next to the other, they kind of join, do they?
683
00:13:54,580 --> 00:13:57,540
There's a bit of a joint between them? There is, yeah.
684
00:13:57,700 --> 00:14:00,180
On the edge of each pile, there's what is called a clutch.
685
00:11:49,180 --> 00:11:51,660
His other hits include the Severn Bridge
686
00:11:19,660 --> 00:11:22,100
Surprisingly, the man who defeated him,
687
00:11:22,260 --> 00:11:24,380
Conservative Prime Minister Ted Heath,
688
00:11:24,540 --> 00:11:26,140
revived the scheme.
689
00:11:26,300 --> 00:11:29,340
Heath had plans for a new industrial county
690
00:11:29,500 --> 00:11:31,300
called Humberside.
691
00:11:31,460 --> 00:11:33,380
It would take in the whole estuary
692
00:11:33,540 --> 00:11:35,980
from Hull to Grimsby, and beyond,
693
00:11:36,140 --> 00:11:38,020
with a new bridge at its heart.
694
00:11:39,580 --> 00:11:42,980
Leading the project would be the firm of Freeman, Fox & Partners,
695
00:11:43,140 --> 00:11:45,020
run by Sir Ralph Freeman.
696
00:11:45,180 --> 00:11:49,020
Freeman was the world's best suspension bridge engineer.
697
00:14:00,340 --> 00:14:02,540
So, one is...it's a curve of steel one way
698
00:11:51,820 --> 00:11:53,980
and the Forth Road Bridge.
699
00:11:54,140 --> 00:11:57,620
If Sir Ralph could make this ambitious design a reality,
700
00:11:57,780 --> 00:12:00,540
it would be the pinnacle of his career.
701
00:12:00,700 --> 00:12:04,660
Ground was finally broken in July 1972.
702
00:12:07,180 --> 00:12:09,220
If you stand here and look out
703
00:12:09,380 --> 00:12:12,540
over what was the biggest suspension bridge in the world,
704
00:12:12,700 --> 00:12:17,340
you might have a job puzzling out just where they started building it.
705
00:12:17,500 --> 00:12:20,260
I mean, how do you get two enormous cables
706
00:12:20,420 --> 00:12:22,340
weighing 5,000 tonnes,
707
00:12:22,500 --> 00:12:25,380
155m up in the air,
708
00:16:09,540 --> 00:16:13,580
they'd now cast a huge slab of concrete into the hole -
709
00:15:33,860 --> 00:15:35,980
At the Humber Bridge construction site,
710
00:15:36,140 --> 00:15:39,940
hundreds of tonnes of sheet piles were driven deep into the riverbed,
711
00:15:40,100 --> 00:15:44,420
forming a dam of steel around the location of each tower.
712
00:15:44,580 --> 00:15:48,140
That allowed diggers to excavate the area inside the dam,
713
00:15:48,300 --> 00:15:50,980
without fear of the walls caving in
714
00:15:51,140 --> 00:15:53,540
or the hole filling with water.
715
00:15:53,700 --> 00:15:55,540
Once the hole was deep enough,
716
00:15:55,700 --> 00:15:59,820
the next major step could take place - filling it in again,
717
00:15:59,980 --> 00:16:04,100
because a strong foundation made of solid concrete was needed
718
00:16:04,260 --> 00:16:07,460
to support the first of the two towers.
719
00:16:07,620 --> 00:16:09,380
A year and a half into the project,
720
00:15:30,300 --> 00:15:33,700
Everyone's happy. Job well done.
721
00:16:13,740 --> 00:16:19,540
44m long, 16m wide and 11m deep.
722
00:16:19,700 --> 00:16:22,260
It's still there, hidden away under the beach.
723
00:16:22,420 --> 00:16:24,460
And so, the time had come to begin
724
00:16:24,620 --> 00:16:27,740
the first really revolutionary feature of the bridge -
725
00:16:27,900 --> 00:16:31,580
a 155m-tall tower,
726
00:16:31,740 --> 00:16:33,900
to be made, for the first time anywhere
727
00:16:34,060 --> 00:16:37,260
on a long-span suspension bridge, out of concrete.
728
00:16:38,980 --> 00:16:41,060
Concrete is magic stuff.
729
00:16:41,220 --> 00:16:42,700
When it's first mixed,
730
00:16:42,860 --> 00:16:45,820
it can be poured or moulded into almost any shape.
731
00:16:45,980 --> 00:16:49,140
And when it sets, it's as tough as stone.
732
00:14:36,740 --> 00:14:39,500
Yes, that's the one. Here we go.
733
00:14:02,700 --> 00:14:05,180
and then it's curved the opposite way on the next pile,
734
00:14:05,340 --> 00:14:07,660
so that helps the two piles interlock.
735
00:14:07,820 --> 00:14:11,580
And then the vibrating hammer essentially just vibrates the pile
736
00:14:11,740 --> 00:14:13,060
at a very high frequency
737
00:14:13,220 --> 00:14:16,180
and that's what helps drive that pile down into the ground.
738
00:14:16,340 --> 00:14:19,580
Essentially, it's using brute force... It is, yeah.
739
00:14:19,740 --> 00:14:21,860
..to get this sheet down into the ground.
740
00:14:23,620 --> 00:14:25,980
That's very clever.
741
00:14:26,140 --> 00:14:29,260
Now I understand the idea behind pile driving,
742
00:14:29,420 --> 00:14:33,100
Phil is letting me put the theory into practice.
743
00:14:33,260 --> 00:14:36,580
So, by doing that we're going to, what, just build up the pressure in the hydraulics?
744
00:00:01,740 --> 00:00:04,860
ROB BELL: Britain's iconic bridges,
745
00:14:43,260 --> 00:14:45,300
Away it goes.
746
00:14:45,460 --> 00:14:47,180
(LAUGHS)
747
00:14:47,340 --> 00:14:49,620
And down it goes, I mean look at it!
748
00:14:51,300 --> 00:14:54,820
What is here just a small flick of a switch...
749
00:14:54,980 --> 00:14:58,700
..triggers an enormous amount of power over there.
750
00:15:01,740 --> 00:15:04,820
This is high-tech equipment doing its job.
751
00:15:06,900 --> 00:15:11,220
It's powerful, it's unforgiving, and it's bloomin' loud.
752
00:15:13,260 --> 00:15:16,500
It's the Gordon Ramsey of the construction industry.
753
00:15:20,020 --> 00:15:22,500
Here we go, look, that's it. That's the signal.
754
00:15:26,740 --> 00:15:30,140
Just giving it a quick check there to make sure it is nice and level.
62331
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