Humber Bridge

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WHAT IS THE HUMBER BRIDGE?

It is a suspension bridge, crossing the river Humber from Hessle on the northern, or Hull side of the river, to Barton on the Lincolnshire or southern side. As with the suspension bridge at Clifton, this is purely a road bridge - albeit a vastly larger one - with a separate pavement and cycleway on each side of the dual carriageway.

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When opened by the ...
...Partners, consulting engineers on the Humber Bridge project (almost unbelievably since 1928!) was a company founded by Sir Charles Fox, a railway engineer by trade, who received his knighthood for …… building the Crystal Palace in Hyde Park!

Nobody could accuse the Humber Bridge of not having an illustrious pedigree!

Where other such ventures were praised and publicised for all the right reasons, this one was bound ... more

Whilst an enthusiasm for the Clifton Suspension Bridge, or the Forth Rail Bridge may be understandable, the third in my series of bridge reviews is probably rather less so. Indeed, this particular bridge has recently featured on these very pages, and for good reason, as being an economic millstone to the Humberside area and a drain on the finances of local residents, who have little other choice but to use it in their daily commute, paying through the nose for so doing. Two factors, I am sure, very much at odds with its original conception.

My review here is not politically motivated, although I do strongly support the locals' views and urge you to follow the links that I am publishing at the foot of this review.

OK that's the party political over with - until the end.

WHAT IS THE HUMBER BRIDGE?

It is a suspension bridge, crossing the river Humber from Hessle on the northern, or Hull side of the river, to Barton on the Lincolnshire or southern side. As with the suspension bridge at Clifton, this is purely a road bridge - albeit a vastly larger one - with a separate pavement and cycleway on each side of the dual carriageway.

PLAY FANFARE NOW!

When opened by the Queen, on 17th July, 1981, this bridge was the stuff of the record books. The biggest, the best, the latest achievement of British engineering and design, it joined such legends as the Titanic, the Crystal Palace, the Millennium Dome….woops sorry, 19 years later, but I think you get the picture.

The Crystal Palace? Well there is actually an intriguing link between that, brainchild of Prince Albert, and this bridge opened 130 years later. Freeman Fox and Partners, consulting engineers on the Humber Bridge project (almost unbelievably since 1928!) was a company founded by Sir Charles Fox, a railway engineer by trade, who received his knighthood for …… building the Crystal Palace in Hyde Park!

Nobody could accuse the Humber Bridge of not having an illustrious pedigree!

Where other such ventures were praised and publicised for all the right reasons, this one was bound up in seedy politics and dubbed by many as "The road to nowhere". As a project, in public relations terms at least, it was something of a disaster, a white elephant that nobody seemingly managed to positively spin.

All of which, as far as I am concerned, as an engineer and bridge enthusiast, is to sell the efforts of a great number of people short. The Humber Bridge was for seventeen years the longest single span suspension bridge in existence. Incidentally it is now the worlds fourth longest such bridge.

REWIND THE CLOCK…..TO THE YEAR 1315

Historically prior to the era of road transport, the Humber played a pivotal role in the transport system in the north east of the country. Anything that was heavy and required moving was transported on water - the Humber providing access to the rivers Trent and Ouse, many towns, York, most notably, had thrived and prospered thanks to the presence of the Humber leading into the North Sea. Equally it had always proved a barrier to north / south communications on the eastern coast, probably more to the detriment of the towns bordering the northern banks.

However, due to the North Sea and continental trade - as well as that of the English coastal waters - many prospered on the banks of the River Humber, small docks and jetties were built on both banks, businesses thrived. Although ferry services are known to have been here spasmodically since 70AD, it is surprising that it was as late as 1315 that a permanent ferry service was established between Hull and Barton. On foot, at that time, it cost half a penny; take your horse too and the charge doubled!

As in so many other things, the Industrial Revolution brought about vastly accelerated growth in trade, requiring the expansion in ferry services across the Humber. Primarily these were set up between Hull and New Holland - a shorter crossing than the one to Barton. With the coming of the railways in the first half of the nineteenth century, as elsewhere, Hull started to expand rapidly. This expansion remained held back due to the Humber and limitations of the ferry services, some of which had been acquired by the Manchester, Sheffield and Lincolnshire Railway.

By 1860 the ferry was causing such a bottleneck that various crossing schemes started to be investigated. Naturally it was primarily the concern of the railway companies of the day; road transport was almost non-existent, certainly commercially. For the next sixty eight years various discussions took place, some even venturing to suggest tunnelling under the Humber.

THE CITY OF HULL COMMISSIONS A FEASIBILITY STUDY

The main driving force behind a crossing emerged in 1928: Hull City Council invited Freeman Fox and Partners to undertake a crossing feasibility study. In that year, the current location of the bridge was actually 'fixed' as the most appropriate crossing point - be it by bridge or tunnel.

In terms of the technology of the day - bearing in mind that the Humber river traffic still had to travel east to the sea and Hull docks, a tunnel must have looked an attractive proposition. Any bridge constructed would need to be not only colossal in length, but also high enough to allow passage of ships at high tide. It was decided that a clearance of 30 metres would be required.

The project, as it had now become, was in danger of being terminated by the depression in 1931, there were simply no available funds for such a hugely costly undertaking.

In 1935, Ralph Freeman, who was in charge of the planning (Sir Douglas Fox being the engineer in charge), laid out the current span and alignment of the bridge. Only a suspension bridge would allow sufficient clearance above high water, without requiring additional supports which would cause the shifting sands of the estuary to silt up, thus impeding river traffic.

However, the design specification must have looked like the work of science fiction to the draughtsmen, let alone laymen, of the 1930's - the required central span was calculated to be 0.85 mile (1372 metres) long! Designing such a colossus was one thing, the technology to build, what was to be FIFTY years later, the world's longest single span suspension bridge, was something else entirely.

The Second World War and following economic gloom ensured that Mr Freeman's plans went no further than the drawing board, indeed, it was 1955 when Kingston Upon Hull Corporation requested a new bridge plan to be drawn up - simultaneously promoting a parliamentary bill. The Humber Bridge Bill was passed the following year, effectively setting up the Humber Bridge Board in order to manage and raise funds for, not only the building of the bridge, but the purchasing of all the land required for the building of the approach roads required.

Following various detailed studies the government, in 1971, agreed to loan the Humber Bridge Board the finances required.

In 1971 the estimate to build the bridge was a mere £28 Million.

The timing of this was rather ill-feted. The fuel crisis was just about to wreak its terrible affect on the world economy, here in Britain strikes were the order of the day, both factors fuelled rapidly increasing inflation. Unavoidably, this lead to hugely escalating costs on this, the worlds' premier engineering project of the day.

WHAT EXACTLY DOES THE HUMBER LOOK LIKE HERE AT HULL?

Many of you who do not know the area, or who have not studied it in geography classes, may be starting to wonder just what all the fuss is about; bridges, ferries, tunnels to cross a river?

Well, I got a big surprise when I first actually saw the Humber about ten years ago. Looking at it on a map does not really prepare you for the reality; this is not a river comparable to the Thames in London - or even the Thames at Thurrock, this is a large, open expanse of water. On a rainy or misty day you cannot see the opposite bank. At the crossing point chosen for the bridge, the distance between the banks must be around a mile.

NOW LET'S BUILD THE WORLD'S LONGEST BRIDGE

In 1981, when opened, the central span of the Humber Bridge at 0.88 miles (1410 metres) was the worlds longest. Unlike other similar bridges - most notably the Seven and Bosporus (both by Morgan Fox) - the Humber Bridge has unequal span lengths leading onto that vast central one. To the north at Hessle the span is 918 feet (280 metres) the one at Barton, to the south, being almost twice as long.

Whilst the scenery of the area - flat on the Lincolnshire side, rising to the north at Hessle - is hardly inspiring, the designers were keen that the bridge should enhance, rather than be a blot on the region's landscape. With the main towers being 510 feet high (155.5 metres) it did not take a genius to realise that this man made structure would be a major land mark for many miles around.

As is so often the case with engineering projects of any scale, designing the item in question very often proves to be the "easy" part in relation to the actual construction. That very much turned out to be the case with the Humber Bridge! The requirement in this case turned out to be (quite literally) the digging of TWO huge money pits. The geography and, more importantly, geology at either end of the bridge were entirely different. Whilst above the water line the main towers look identical, due to the nature of the river bed and shore anchorages, two entirely separate construction projects had to be set up at either end of the yet to be built bridge. Indeed, the Hessle pier on which the northern tower is standing is land based, whilst the Barton tower sits on top of an enormous cofferdam - a man made island, created from sections of concrete and steel.

The land based pier was relatively straightforward in construction terms - the cofferdam far from it. The Humber river bed was known to be problematic due to its fast currents, soft bottom and rapidly shifting sands all of which caused changes in depth that were impossible to accurately predict. Sinking large sections of concrete into the sand, to be anchored on the rock below was already known to be an unpredictably risky venture. Once completed, the cofferdam proved to be unstable - certainly unable to support the massive concrete and steel tower required to suspend the bridge.

The solution to the instability problem was on an equally giant scale to the project itself. They tipped 12,000 tonnes of block chalk and sand bags around the base of the cofferdam. Once stabilised, the huge task of surrounding the concrete cofferdam in steel casing, creating a water tight caisson could begin. Once the ring of steel was complete, the next step was to fill it with concrete, adding to the weight and, gradually filled three metres at a time, causing it to sink, biting into, and anchoring it on, the river's rock bed. This whole operation had to be done twice over - each of the towers being planted on top of a caisson.

As well as foundations for the towers, early stages of the building work involved deep excavations for the cable anchorages. For those of you not familiar with suspension bridges, the deck - or roadway in this case, as with the Clifton Suspension Bridge, is suspended from cables "hung" from the towers. Obviously these cables have to be anchored securely back on dry land, the towers acting as tensioners for them.

Again, thanks to the geology, these anchorages had to be designed completely differently north and south - on the Hull side solid chalk formed a stable rock base. Dig a 20 metre deep pit, fill it with reinforced concrete slabs and then when ready feed the cable ends into a ready made splay chamber. In total there are 190,000 tonnes of concrete in the Hessle cable anchorage. Another massive individual project, but technically nothing out of the ordinary……

……unlike at Barton. Here, the underlying material was Kimmeridge Clay - a far less stable material than chalk. The whole anchorage chamber required underpinning with concrete and specially manufactured steel chambers which were then filled with liquid concrete - 300,000 tonnes of it!

By now, mid way into the building programme £98 Million had been spent with more to follow - plenty more!

THE TOWERS

We already know that, at 155.5 metres in height, the four concrete towers were destined to be the most prominent aesthetic feature of the bridge. Each of these steel reinforced concrete towers is 19.5 foot (6 metres) square at the base, gently tapering towards the top which is 14ft 7ins (4.5 metres) x 15ft 6ins (4.75 metres). The matching pairs of towers were built simultaneously, using a special cradle which saddled them and rose hydraulically as they went up. A statistic that I found fascinating is that the average rate of climb is quoted at 76.4 millimetres per hour! This work carried on day and night - there were two twelve hour shifts employed to raise the towers. Once raised to their full height, the four cross braces were constructed.

Due to the problems with the Barton caisson, the Hessle tower was finished well before work was able to start on the southern one.

ENOUGH CABLE TO STRETCH ONE AND A HALF TIMES AROUND THE WORLD

With the framework (towers and anchorages) complete, the next job was to raise and attach the cables. Hoisted to the top of each of the four towers was a pre-fabricated 45 ton saddle unit, the vital component over which the cables hang.

The next part of the operation - as far as I am concerned at least - is actually the most fascinating of all. A walkway had to be suspended from one tower to the next, following exactly the same "drop" as the completed cables which were to be hung a metre above them. The walkway was constructed from a series of wire ropes - which were first secured at the Hessle anchorage before being hoisted up and hung over the Hessle tower. They were transported across the river by a tug and then raised up, again by crane mounted on top of the Barton tower and sent down to the anchorage beyond.

In total there were nine wire ropes hung for each of the two walkways. Each one required the closing of the Humber to river traffic, an operation carried out at low tide in order to minimise disruption to this busy channel.

Once the wires were safely in place, a mesh was attached to form the floor and sides of the walkway, cross walkways allowing access to the east and west cables were constructed, linking the two together at regular intervals.

The next apparatus to be constructed very much resembled that of a ski lift, indeed it was referred to as "the tramway". This allowed the very complex wire spinning gear to play out the individual strands of wire starting at the Hessle tower. The wire was not 'platted' as with traditional rope. The completed cable was made up from 37 strands, each consisting of 404 individual wires. Once the 37 were in place they made up a hexagonal shape in section, which then required compacting into a 700mm diameter circle - this was done with a compacting machine applying 360 tonnes of pressure, working its way down the tramline over the full length of the cables.

Having been compacted, the cables were simultaneously coated with read lead paste and wrapped - again carried out by a purpose built machine running down the tramway. This operation could only be carried out once the deck hangers had been put into position and the roadway section hung beneath. Finally five coats of paint were applied by hand to provide a weather proof finish.

NOW ALL WE HAVE TO DO IS HANG A FOUR LANE DUAL CARRIAGEWAY FROM IT

The wires that actually suspend the road, over which some of you drive every day, are known as the "hangars". The positioning and length of these was determined by computer calculations carried out at a very early stage in the design. I was surprised to read that they are only 62 millimetres in diameter. The road, weighing over 17,000 tonnes hangs from wires less than two and a half inches thick!

In terms of a bridge, rather than the roadway, we refer to the assembly hanging from it as the "deck". In the case of the Humber Bridge, the deck is actually a series of pre-manufactured sections - each 18.1 metres long and weighing 140 tonnes. These were manufactured in a large yard further inland on the Humber and then transported to the bridge site by barge.

Using a hoisting carriage suspended between the two main cables, once the barge was positioned under the planned site the deck section was raised until it could be attached to the hangars. The first section to be lifted was the central one in November 1979. Due to the ever changing stresses on the cables as each section was hung, two sections were hung each day in order to maintain a balance. As the sections were hung, they were temporarily connected at deck level - with slack connectors allowing each section to move independently as further sections were added changing the angles and heights as the cables gradually assumed their final shape and drop.

Once all the deck sections were in place, the final welding operations could take place - this being done from the underside of the bridge. An unexpected hiccup was that although the sections of roadway on top actually matched up, the prefabricated sections were wide apart underneath. In order to weld them together hydraulic jacks had to be brought in to force them together.

Over the top of the steel deck, once fully assembled and inspected for faults a road surface had to be laid. In the case of a steel bridge deck like this obviously the road surface has to perform more than just provide a safe and comfortable driving surface. It also has to permanently seal the steel deck below. The road, with a total surface area of 40,000 square metres on the bridge, is a 38 millimetre layer of mastic asphalt, laid on top of a bituminous primer, further coated with rubberised bitumen.

In total 3,500 tonnes of asphalt sits on top of the bridge deck.

This being a suspension bridge, there is considerable movement designed into it, allowing for variations in loads on the bridge and weather conditions. This is allowed for by the provision of large expansion joints located beneath the towers, at each end of the bridge a total movement of 2.9 metres is provided for.

OK, STICK UP THE LIGHTING AND GIVE THE QUEEN THE SCISSORS

The finishing touches were put on the bridge in the first half of 1981, before traffic first started crossing it on 24th June. By the time the Queen arrived here to perform the opening ceremony, the bridge had become an important part of the Humberside region, not to mention being a land mark upon it.

SIXTEEN YEARS LATER ……. RICHADA TURNS UP HERE

Always having had a fascination for grandiose engineering projects, I would like to say that the draw towards this one was simply too strong to resist……

……I would like to say that, but, until 1997 I had had no reason to visit this area of the country. One day in May of that year, I was an hour and a half early for a business appointment in nearby Brough - right on the Humber's edge. In order to kill an hour or so, I decided to visit Hessle in order to see and photograph this well known landmark. It was a bright, sunny day and I remember being absolutely staggered by the sheer size of the car and coach park at Hessle. What on earth could possibly go on here I wondered?

There were a few other cars and a mini-bus (school field trip probably), people walking dogs, and, oh yes and talking of dogs, a row of hot dog stalls lining the western side of the car park. It crossed my mind, that, open as these fast food vendors were, this looked like a pretty futile way of making a living to me.

There is here the Humber Bridge Country Park, an area largely of woodland, some of which offers views of the bridge, but from my visits since, this would appear to be a rather unused amenity, although admittedly I have only been here during the week.

I had long promised to take Mrs R to Hessle to see the bridge - climbing the steps from the car park onto the bridge just before the Hessle Tower, she was rather, like me, slightly under whelmed by the site in front of her. It is difficult not to be awe struck by the sheer scale of the thing, but due to its very simplistic concrete design it offers little of the aesthetic pleasure provided by the Clifton and Forth bridges.

In all weathers, at any time of the year, a walk on the Humber Bridge is a truly bracing, if less than rewarding experience. I in no way wish to denigrate the Humberside area, indeed, I have never met a resident of Hull that I did not like (and I have met quite a few!), but, in reality, there is really very little to see from this bridge. A vast expanse of muddy water is below you, a flat undulating countryside to the south and nothing particularly inspiring to the other three compass points either. The Humber Bridge itself is the tourist attraction here, and let's face it, how many are as enthusiastic as I about bridges?

The photographs that you see below - at least my six, were taken in December 2006, we posed on the bridge, got thoroughly battered by the wind and ran for the cover of the car, sitting that day with just one other on that vast car park!

We did visit the excellent and friendly little Tourist Information Centre - in a Portakabin - on the north end of the car park, here many Humber Bridge (and South Yorkshire) souvenirs can be purchased - at quite reasonable prices.

A FEW FINAL (I PROMISE!) WORDS:

On its opening day the Humber Bridge had cost the government £151 Million to date. Whilst in the following years the bridge has made an operating profit, it has not been enough to cover the interest on the loan, the scheduled break even date of 2032 looks increasingly optimistic. The bridge was designed incidentally to last 120 years!

You can currently walk or cycle across the bridge for free.

Motorcyclists pay £1.20 each way

Cars £2.70

Commercial vehicles between £10.90 and £18.30 depending on weight.

Through this extortionate charging system, the bridge that was intended to liberate the area, leading to commercial growth is having exactly the opposite effect in choking off trade and communications.

http://petitions.pm.gov.uk/Humber-Bridge

www.humberforum.co.uk/newss tory.asp?id=178

With grateful thanks to Ciao member, and Humber Bridge authority, Silverback for permitting the use of his links……just hope that some of the technical details contained herein do not make you think twice about driving onto the bridge!
 

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