Tag Archives: UK

Cost of Corrosion Increase – Forth Road Bridge

Significant inaccuracies in the as-built drawings for the Forth Road Bridge’s cable anchorages are to dramatically increase the cost of corrosion investigations, the “New Civil Engineer” publication learned this week.

Examination of the bridge’s southern anchorages – which hold the huge suspension cables in place – is taking much longer than anticipated because they are deeper and steeper than the on the original as-built drawings.

The Forth Estuary Transport Authority (Feta) is investigating the condition of the 48 year old anchorages after a resident engineer’s report raised concerns about the possibility of corrosion in the post tensioned strands within them.

In a capital update report to the bridge authority, Forth Road Bridge chief engineer and bridgemaster Barry Colford says the cost of the inspection is likely to be “significantly higher than the original estimate” of £3.5M.

“It’s a very resource driven contract,” Colford told NCE. “As the rockhead level was higher and there more was concrete [than anticipated] the contractor has had to spend more money.”

 

The anchorages are four concrete filled tunnels – 80m deep on the south side, 57m deep on the north side – and up to 14m in diameter.

The anchorages each transfer a load of 14,000t from the main suspensions cables into the bedrock.

Each anchorage consists of 114 ducts with four post-tensioned, galvanised, 32mm diameter high tensile steel strands made up of 19 wires in each.

With the original access chamber to the bottom of all four anchorages filled in, the only way to assess the condition of the strands is to dig down and open them up, said Colford.

Contractor Graham began the anchorage investigation on the southern bank in August 2011 under a New Engineering Contract (NEC) 3 Option C target cost contract with a target cost of £3.5M.

But after investigations began, engineers discovered that the ducts were 400mm deeper and were at an angle of 33˚, not 30˚ as recorded on the as-built drawings.

“It’s a significant change to what we expected and it is very disappointing the as-built drawings of a major structure were not correct,” added Colford.

Graham will begin exposing up to nine stands on each of the southern anchorages by the end of the year. Consultant Fairhurst will assess the strength of the anchorages by the end of 2013.

Colford is in discussions with Graham about the size of the compensation event – the cost of work unforeseen at tender stage – and £220,000 has already been agreed.

The extra funds for the anchorage investigation are contributing to an overall deficit of £3.5M in Feta’s capital budget for 2012/13.

Its capital funding was cut by 58% by Transport Scotland last year.

Colford said budget shortfall would be met by using some of Feta’s £5.8M reserve, as well as delaying or cancelling “non-committed” schemes on the bridge.

He was also seeking additional funds from Transport Scotland.

SOURCE: http://www.nce.co.uk/news/structures/forth-anchor-corrosion-probe-costs-pushed-up/8635624.article?blocktitle=Exclusive-news-from-NCE-magazine&contentID=204

Manx2 crash landing was caused by corrosion

Air accident investigators have confirmed that mechanical failure caused an aircraft to crash land at Ronaldsway.

The UK-based Air Accident Investigation Branch has issued a safety recommendation to the European Aviation Safety Agency following the accident.

Emergency services were called into action at just before 6pm on Thursday, March 8, when the Manx2 service from Leeds Bradford Airport got into difficulties after landing at Ronaldsway.

Twelve passengers were escorted shaken but unharmed from the aircraft which was operated by Lincolnshire-based Links Air, on behalf of Manx2. The two crew members also escaped unscathed.

Now a preliminary investigation by the AAIB has concluded that a corrosion crack in a metal component caused the right hand landing gear of the Jetstream to collapse, resulting in the plane skidding along the runway on its wingtip and coming to rest in the grass at the side.

The AAIB found that the accident was caused by stress corrosion cracking in a metal component at the top of the right main landing gear leg.

Its report describes how almost immediately after the aircraft touched down it leaned to the right and there was an unusual noise.

Investigators say that the corrosion was not detected by a visual inspection carried out 11 days before the incident nor during a test of the landing gear completed 10 months before – although the amount of corrosion in the crack and on the steel spigots suggest it was present then.

As these inspection requirements didn’t detect the crack, the AAIB has issued a safety recommendation to the European Aviation Safety Agency that it review the effectiveness of an airworthiness directive in identifying cracks in the yoke pintle housing on landing gears fitted to Jetstream 31 aircraft.

SOURCE: http://www.iomtoday.co.im/news/traffic-and-transport/manx2-crash-landing-was-caused-by-mechanical-failure-1-4384557

Ipswich port worker’s tyre burst death ’caused by corrosion’

Corrosion of a fork-lift truck wheel was a “likely scenario” when a tyre exploded fatally injuring a worker at a Suffolk port, an inquest heard.

Gary Deaves, 48, an Associated British Ports (ABP) mechanic at Ipswich Docks died from head injuries after the tyre he was removing exploded in 2010.

Mr Deaves, of Ipswich, was injured as he removed the wheel from a 1979 Hyster Challenger truck for maintenance.

The accident happened on 30 March 2010 at the ABP workshop on Cliff Quay.

An ABP safety officer said it was the first case of this sort the company had heard of.

Brain injuries
The inquest heard the tyre exploded, propelling the wheel off the axle of the vehicle, which was raised off the ground.

Mr Deaves was treated for head and brain injuries at Ipswich Hospital and later at Addenbrookes Hospital, Cambridge, but died on 9 May 2010.

Health and Safety Executive inspector David Gregory told Ipswich Coroner’s Court that although there were “always alternatives” the “likely scenario” which he believed was “that the flange ring [of the wheel] became detached because of age and corrosion.”

He said the explosion would not have happened if the tyres had been deflated, but that it was not standard practice to do this before they were removed.

Andrew Bowley, ABP’s safety manager, told the court it was now standard procedure to deflate all tyres before removing wheels from axles.

Mr Bowley’s written statement was read out by the coroner: “In my 37 years, I’ve never known rims come off like this.”

The court also heard from Mark Betts, who was working on the truck with Mr Deaves, who said he “saw no problem with the wheels” before they started removing them.

They had already taken two of the truck’s wheels before the accident happened.

The inquest continues.

SOURCE: http://www.bbc.co.uk/news/uk-england-suffolk-16586243

Playground equipment removed after safety failure

A playground in County Durham (UK) has been reduced to just one toy after its other rides and equipment were removed for failing a health and safety inspection.

For years Allergate play area in Durham City had swings, a see-saw and slides, but they have now been taken away, leaving just a spring-mounted toy bike.

The council said there were no immediate plans to replace the equipment which was “corroded”.

But local mother Ruth Pierce said there was nothing wrong with the toys.

Ms Pierce, who has a two-year-old son Joe, said: “We only walk through the park now – there is nothing to come here for.

“I’m all for things being safe but there is a limit – there was nothing wrong with the equipment, except perhaps the roundabout which was a bit dodgy, but the rest of it was all fine.”

Steve Howell, head of sport and leisure at Durham County Council, said the authority had spent more than £1m on improving its playgrounds in the past year.

He said: “All the council’s play areas are regularly inspected by trained staff to ensure they do not pose a risk to the children coming to enjoy them.

“In this case the inspection showed significant corrosion on all equipment which could not be safely repaired.

“While play areas are covered by range of background legislation including health and safety regulations, the most important thing is for staff to use their training and common sense.

“If a piece of equipment represents a potential hazard the safest thing to do is take immediate and appropriate action.”

He said that this was the first time the council had removed play equipment without “prior notice”.

SOURCE: http://www.bbc.co.uk/news/uk-england-tyne-16077237

British engineers help to save WWII Dornier Do-17 German bomber from its last battle – Corrosion

Researchers from Imperial College London are working with the Royal Air Force Museum to clean the Dornier Do-17, known as The Flying Pencil (Fliegender Bleistift), and prevent further corrosion once it is removed from the water.

In 2010, shifting sands uncovered the aircraft, which lies off the Kent coast and was previously protected by layers of sediment, exposing it to the corrosive effects of seawater and threatening to destroy the aircraft entirely.

Dr Mary Ryan from Imperial’s Department of Materials, who is working on the project, said: ‘This is the last remaining intact Flying Pencil of its kind in the entire world, so the significance of this project to our history cannot be underestimated.”

‘We have been analyzing fragments already brought to the surface and it is absolutely fascinating to see how this bomber, which crash landed more than 70 years ago, has been so well preserved by the layers of sand.’

One of the challenges for the Imperial team is devising a method for cleaning and removing the corroded layers from the Flying Pencil’s aluminium fuselage, which contains large amounts of the corrosive agent chloride from the seawater.

The researchers are currently testing a solution based on citric acid, which is found in high concentrations in citrus fruit, to remove the surface layers of corrosion and sea deposits such as crustaceans from small pieces of wreckage already retrieved.

The aim is to develop a solution that is powerful enough to clean the bomber, but not so powerful that it damages any remaining paint and markings on the aircraft, which are of historical significance. Any remaining chloride on the metal surface could lead to further attacks of corrosion when the plane is on display.

The Imperial team will also help to work out the best environmental conditions for displaying the bomber in the museum. For example, too much humidity in the air could lead to condensation on the metal, which would activate further corrosion.

Once the research is complete, a team from the museum, working with specialist underwater archaeologists and recovery experts, will use a lifting cradle to support the weight of the fragile aircraft as it is brought to the surface, currently planned for spring 2012.

The Flying Pencil was brought down by the RAF on 26 August 1940, during the height of the Battle of Britain while en route to attack airfields in Essex with a large German formation.

It crashed into the shallows off Goodwin Sands killing two of the crew members, who were later recovered and buried in a military cemetery. The other two crewmen were taken prisoner.

Ian Thirsk, head of collections from the Royal Air Force Museum, said: ‘At the moment, we are attempting to trace the relatives of the crew members who survived this fateful mission, in order to help engage visitors to the museum about the human story behind this episode of the war.

‘As the last surviving example of the Dornier Do-17, this aircraft is truly unique. We think this old bomber has one last scrap left in her — the battle against corrosion.’

Once the aircraft is lifted from the seabed, it will then be transferred to the museum’s conservation facility at Cosford, and then placed on display in the planned Battle of Britain Beacon Wing at the museum’s London site.

SOURCE: http://www.theengineer.co.uk/sectors/aerospace/british-engineers-aid-attempt-to-save-german-bomber/1010776.article

Research at Hertfordshire University (UK) into Reducing Corrosion in Steels

Research which looks at how application of electromagnetic fields (EMF) of high intensity to steel can protect against corrosion and make savings of 50 percent is being carried out by researchers at the University of Hertfordshire.

Dr Andreas Chrysanthou and Dr Anatoli Babutskyi at the University’s School of Engineering and Technology have been awarded €278,680 for a two-year FP7 Marie Curie International Incoming Fellowship (IIF) project to investigate the effect of EMF on the properties of structural metals.

“Our previous work has shown that using electromagnetic treatment as a post-processing routine increases corrosion resistance in steel by about 50 percent,” said Dr Chrysanthou. “Now we need to understand the microstructural effects that take place when the field acts on the steel.”

According to Dr Chrysanthou, although they have carried out seven previous studies that show that their approach works, the technique is underexploited because the effect of the EMF on the microstructure of the steel is not yet fully understood.

“The effects of corrosion and conventional methods undertaken to protect against corrosion are very costly and most countries spend between three to four percent of their GDP on it,” said Dr Chrysanthou. “When we have established how exactly this technique works, it will be a useful cost-saving tool for the automotive, construction, defense and aerospace industries.

SOURCE: http://www.azom.com/news.aspx?newsID=30796

Footbridge closed as it’s ‘dangerous’ due to corrosion

THE INSPECTION in the United Kingdom which led to the closure of the footbridge to Whitby’s West Pier extension has revealed a long standing history of corrosion and decay.

Scarborough Borough Council’s report, compiled the day after the inspection a fortnight ago talks of “corrosion”, “failure” and “dangerous”.

The inspector examined the primary beams which are positioned at either side of the bridge and secondary beams which sit between them and support the wooden decking which pedestrians walk on.

Findings suggest the beams have not been painted or treated for some considerable time and given the exposure to airborne seasalt this has accelerated corrosion.

The report states: “The primary and secondary beams may once have been painted but there is now no evidence of a painted surface to any of the beams or associated fixings.

“This has resulted in significant corrosion leading to delamination which can be expected to result in a significant reduction in functionality.”

The primary beams which span 11.7 meters and 13 meters are undersized for the load it is carrying according to current British standards.

Furthermore supporting steel work appears to be 20% corroded and associated fixings are “exhibiting signs of extensive corrosion greater than 50% of their net cross section which could lead to failure of the beams.”

The balustrade posts and railings are painted but spot chips and cracks in the finishing coat were noted along with corrosion staining.

But the metalwork which fixed the posts and railings to the bridge are severely corroded.

The report says: “While the balustrade is overall in what can be considered in fair condition, the connection to the primary beam is near to failure and is considered dangerous.”

The report’s suggested future options have done nothing to stop rumors circulating town that the bridge is to be demolished and access to the extension being permanently cut off.

Three possible ways forward include: bridge removal and abandonment of access, replacement of the footbridge in its entirety or another more detailed inspection and refurbishment which would include removing the bridge to allow for the works.

But the report says this could be more costly than replacement.

Council member Joe Plant, who represents the West Cliff ward, said the first he heard of any issues with the extension and the footbridge was when he learned it had been closed along with everyone else and as far as he was concerned demolition or permanent closure “was not an option”.

He told the Gazette: “I have asked the question and in my view we should be looking at replacing the east and the west from the same funding pot.

“I have also asked for the maintenance regime. If this has not been done, why not? I know money is tight at the moment for a lot of things but at the end of the day if you maintain things it will save you money in the long run.”

Brian Bennett, SBC’s head of tourism and culture has said officers are looking at the possibility of re-opening the bridge to limited foot traffic pending a further inspection that requires scaffolding being put up.

This had to be postponed last week due to high winds but Mr Bennett added SBC had been in touch with English Heritage and a bridge manufacturer about a replacement.

If this goes ahead it is likely it will be manufactured off site, then delivered and installed.

SOURCE: http://www.whitbygazette.co.uk/news/local/footbridge_closed_as_it_s_dangerous_1_3790004

Safety scare for North Sea oil rigs

Government safety inspectors have blasted oil companies for failing to deal with serious corrosion on North Sea rigs that could put lives in danger and lead to a disaster.

On one rig corroded pipes led to a “significant quantity” of gas leaking and it was “fortunate” there was no explosion.The revelations are in reports from the Health and Safety Executive (HSE), which launched an inspection program last year over concerns about oil platforms and pipelines which are being used beyond their expected lifespan.

The documents obtained through Freedom of Information by an oilworkers’ union reveal the HSE has issued improvement notices to rig operators after its inspectors found evidence of corrosion that could have resulted in severe damage in at least three installations, two off the Scottish coastline.

Industry representatives said the inspection programme had shown that most rigs had effective anti-corrosion programmes in place.

But the Scottish National Party’s Westminster energy spokesman said the latest reports strengthened the argument for the Scottish Parliament to be given new powers to regulate the offshore industry. The documents have emerged following the leakage of more than 200 tonnes of oil from a pipeline from Shell’s Gannet Alpha, 112 miles offshore from Aberdeen.

The most serious incident revealed by the FoI requests happened in October last year on the Brae Alpha rig, operated by the oil company Marathon around 100 miles north-east of Aberdeen.

According to an official Improvement Notice issued by the HSE, a gas leak on the installation, which has around 100 staff, was only discovered after a worker smelled gas.The subsequent investigation by HSE staff found that “the incident featured an uncontrolled leak of flammable hydrocarbon gas in significant quantity from a pipe near the east side” of the platform. The incident had the potential to cause fire and explosion.”

The HSE pinpointed the source as combined and progressive internal and external corrosion affecting the pipe work. It added: “The issues underlying this show that you have failed adequately to detect the extent and severity of the corrosion.”

It also pointed out no gas detection coverage was available in the area of escape.

The HSE ordered Marathon to review its systems for inspecting for corrosion by March this year.

Another serious example of corrosion involved the Balmoral Platform, operated by Premier Oil, 135 miles north- east of Aberdeen.

Jake Molloy, regional organiser of the RMT union offshore energy branch, said oil companies were showing: “a blatant disregard for workers health and safety.”

Of the Brae Alpha incident, he said: “We find it astonishing that this significant gas leak was only discovered by a worker actually smelling the gas. Well done to the worker and thank God he wasn’t suffering from a cold. But think about it – no gas detection system.

Network Rail Protecting Royal Albert Bridge from Corrosion

Around 50,000 new bolts are being used in Network Rail’s major project, which started in late May, to restore Brunel’s famous Royal Albert bridge that was built in 1859.

These bolts – as ‘precious and mighty as Brunel’s legendary golden rivet bolt’ – will be vital to keep the landmark structure strong for the next century and beyond.

The £10m improvement scheme will see engineers investing nearly 2m hours of work over the next two years to strengthen and repaint Royal Albert bridge, bringing it back to its former glory.

Around 35,000 litres of special paint will also be used to spruce up and protect the bridge’s steel façade from corrosion.

Mark Langman, route director for Network Rail said:

“We have a big task to transform the railway on Great Western in the coming years and the improvement on Royal Albert bridge plays a big part.

“The Royal Albert bridge remains a vital rail link and has carried more than 1 billion tonnes of rail traffic since it was built. This is the most complex refurbishment work ever and our work will inject a new lease of life and keep the landmark bridge robust for many years to come.”

To be carried out in five stages, the work will start concurrently from each end of the bridge and it is carefully designed to minimize disruption to the community and passengers.

The scaffolding will be encapsulated to create a contained safe working environment to prevent dust and debris from falling from the structure and to reduce any noise pollution.

The encapsulation is sealed to help reduce any noise and its roof is also pitched to prevent accumulation of rain water, which could add weight to the structure. In addition, the encapsulation will form a tunnel around the track, so that engineers can continue to access the structure when trains are running.

A large industrial vacuum cleaner will be used to remove all waste, including grit produced during the blasting process. This waste will be removed daily to prevent any contamination to the environment.

The structure was listed Grade 1 in 1952 by the English Heritage, which has also backed this project.