Pont Y Werin bridge rises on rugged hydraulics 19 August 2011

The Pont Y Werin bridge in South Wales, opened last year to span the river Ely and links from Cardiff to Penarth, across the newly developed Cardiff Bay area, is operating smoothly, thanks to its hydraulic controls.

Dr Arash Farahani, of engineering consultancy KGAL, says that the bridge opens and closes to allow river traffic to pass, via a 40 tonne, 30m opening deck – with its hydraulics lifting the deck in just two minutes to 75 degrees, while withstanding wind speeds of up to 25m/sec.

"We developed a system that allows the lifting span to be controlled by two hydraulic rams, with its base end being hinged by means of pairs of 440mm diameter SKF spherical roller bearings, set into a specially engineered deck trunnion," explains Farahani.

"Additional bearings are fitted at the top of the hydraulic rams to enable them to pivot smoothly as the span opens and closes," he adds.

Farahani says that the bearing units are key to the efficiency and safety with which the span moves, as they have to take almost the entire load of the span, which is around 40 tonnes, and withstand extremes of wind and temperature.

SKF developed these bearings not only to provide extremely high load carrying capacities, but also for ease of fitment and inspection, with little or no maintenance required.

The units are from SKF's CC design type, with symmetrical rollers, two window-type steel cages and an inner ring centred via a floating ring between the two rows of rollers. They also feature efficient contact seals on both sides of each bearing unit to retain grease and exclude moisture and contaminants.

Brian Tinham

Related Companies
KGAL
SKF (UK) Ltd

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