Today, our Northern correspondent admires a civil architectural landmark.
The Romans: famous for liking wine, partial to dividing and conquering, proficient with straight ways and bridge building. But what to do when your legions find a wide estuary literally, in the road? Diversions are costly and in this instance, a bridge too far*
Study a road atlas in North Humberside and you will see from Lincoln (Lindum Colonia) the dual carriageway A15 or, to Roman aficionados, Ermine Street, leads to junction 4 of the M180, the A18 to steel town Scunthorpe but also depletes to what is now a minor road. Roman historians believe a ferry crossing was made from either Winteringham or Whitton in order to aim for Eboracum, York. Bronze Age rudimentary boats have been found here too. But a bridge? Just too long an expanse.
Britain’s Victorian industrialists thought a bridge conducive to railway traffic. The engineering prowess was there but the costs were mighty. The idea of a road bridge surfaced in the 1930’s though costs were further down the list containing war. The idea resurfaced in the fifties, with plans drawn up in the sixties but no actual construction began until 1972 again due to costs, legal wrangling and governmental delays.
Eight years later after industrial unrest, spiralling costs, huge engineering problems and abysmal weather, the Worlds Longest Suspension bridge was opened officially by the Queen in 1981. One can walk or cycle the entire length for free. For engined vehicles a toll was always going to the case, proving a sticking point for many years but you have to pay the bill somehow.
Initially, construction costs were £28 million. Even in the early 70’s, the car industry was investing far bigger sums into just one vehicle. Once completed, the final bill was just shy of £100 million; inflation in the UK at the time was huge, 26% per annum therefore the loan increased as rapidly as the Humber tide. The absolute total cost to repay was now 151 million pounds.
Even with high toll fees, the loan would take many years to pay off. As recently as 2017, the tolls were lowered and fixed with modern thinking of paying in advance and discounts for frequent flyers, though it will be the year 2038 before the debt is repaid. The Department for Transport also assisted by waiving a huge amount owed.
Whilst the typical car factory of the 1970’s and 80’s was far from the laboratory type conditions found today, the Humber estuary was a hostile place to build a bridge. Fortunately the engineers had done some homework. Strong winds to contend with, shifting tidal flows, mist and fog lasting for days played havoc with the build.
Now consider some facts; the sheer scale of matters. The bridge is actually in three spans. The Hessle side (nearest to Hull) is 280 metres. The Barton side (Lincolnshire) is 530 metres with the centre section at 1410 metres. 2200 metres or nearly a mile and a half. When you drive across in your MX-5, you are a soupçon over 30 metres above the water, considerably higher when piloting your Scania Highline truck: strong winds close the bridge.
Flat Earth Society members look away now; those 155 metre tall hollow concrete towers are built 36mm apart at the top from the bottom to follow the curvature of the earth. Their foundations are in totally separate sub strata; the north Hessle tower is built into chalk to a depth of eight metres. The caisson, a watertight “island” with which to make foundations holding the Barton tower has Kimmeridgde clay, a tough, difficult substance and being in the estuary, made even more so. The depth of their foundations drops to 36 metres.
Onto the steel wire suspension; the 5mm thick cables run for 71,000 kilometres or in old English, 44,000 miles. Covered in lead paste, then wrapped with galvanised wire before five coats of paints were applied. The bridge has a “life” of some 120 years: does this mean it will fall down in the year 2201? Sadly, I won’t be around to care.
The road deck is made of 124 hollow steel boxes, around 130 tonnes each, constructed downstream and were transported by barge to be hoisted above using the strength of those suspension cables. The first central section took almost a full day to position due to the strong tide. With experience, this was massively reduced to just over an hour per box. Bolted and welded together, the span was complete by summer 1980. The Bostic adhesive, rubberised bitumen and a final topping of tarmac was all that was needed for vehicles to easily drive on to the bridge.
Of course all manner of vehicles were needed and most period pictures show Transit vans, Cortina estates and Beetles along with the larger construction types. The Queens Roller closely assisted by security Jags officially opened the Bridge, opening the way to millions of journeys to the present day.
Rather boringly, on my recent visit to the crossing, roadworks, contra flows and three miles of standing traffic blunted my delight of this engineering marvel. 1st gear crawling eventually led to a county inn where hearty repair was made before contemplative pictures were taken afore a much faster crossing home. Well worth the three pounds (£1.50 per crossing) and steak and ale pie to see the late Bernard Wex monument.
The Humber Bridge is still is in the top ten of longest suspension bridges in the world (number 8) but with this one closer to my home, it will always remain a favourite.
* Some fifty miles west of here, the Romans had a go at building a bridge in a Yorkshire town called Pontefract. Pontus Fractus, Broken Bridge. Enough said.