Final curtain call for outdated cranes
Alex Hughes investigates the options for dismantling when a crane has reached the end of its useful life
Global trade volumes might be increasing year-on-year, but not all existing handling equipment is up to the job of moving it. Cranes that don’t have sufficient outreach to service larger ships are being driven into obsolescence if they can’t easily — and economically — be lengthened, while others are being taken out of service because they fall foul of legislation.
For example, the EU's 2006 Machinery Directive (2006/42/EC), which aims to improve the safety standards of all types of machinery, has been known to prompt crane scrapping or force early upgrades. Thorsten Rolfs, principal engineer for infrastructure in the marine infrastructure and cranes department at DNV GL's maritime branch, is an expert in helping operators to determine which approach to take.
“2006/42/EC is not a standard. A standard is easy to understand: either you fulfil it or you don't. EU directives are less clear cut,” he says.
The machinery directive covers all machinery, so it's not always easy to know whether a port crane is compliant or not. However, the onus is on manufacturers and equipment operators to demonstrate that they have done everything reasonable to reduce risk.
“There isn't a single way to comply with this directive. Operators are free to choose from a variety of solutions; however, all are risk-based,” Mr Rolfs says.
Changing with the times
Operators today realise that they can’t buy a brand new crane and expect it to operate unchanged throughout its working lifetime; they have to continue to show that a risk-based analysis has been carried out, necessary measures adopted, and certification obtained. However, not all cranes operate in the same way at different ports, so the directive is open to interpretation.
“DNV GL looks at how a crane is being used. If we determine that it is non-compliant, we suggest various solutions as to how they can move into compliance,” Mr Rolfs explains.
He gives the example of a crane operating in the Black Sea dating back from before the directive was introduced, which was deemed no longer compliant following a recent DNV GL inspection. However, replacing it with a new crane would have been four times the capital cost of the existing unit.
“Because It wasn't being heavily used, we suggested a step-by-step upgrade and have just issued the final [compliance] certificate as a result of that work,” says Mr Rolfs, noting that partial rebuilds or upgrades are often a cheaper solution to scrapping.
Machinery must be checked a minimum of once a year, but crucially compliance doesn't have a set end date. Furthermore, if new technology becomes available or if an incident occurs then changes have to be made. Even if a crane does start developing problems, it may continue in service, albeit operating with reduced workloads or functionality, until such time as it can regain compliance, but a compliance recovery plan has to be drawn up as soon as non-compliance is recognised.
Cranes with major problems, such as the loss of their safety brake, must be instantly shut down and only re-enter operations once these problems are fixed.
It is not just safety compliance that determines whether a quay crane can remain in operation or not. Sometimes market developments make existing units obsolete.
Recently, TPS, in Valparaiso, had a crane demolished because it was too small for modern requirements; it had been built in 2002.
“Most shipping companies nowadays operate with post-panamax vessels, so you need a gantry crane that can at least reach 22 rows, whereas the maximum outreach of the dismantled crane was just 14 rows, so was clearly inefficient,” a TPS spokesperson told Port Strategy.
TPS, however, retains a similar unit to handle the 3% of non-containerised general cargo that it generates.
O'Brien Demolition was brought in to dismantle the crane, following a recommendation from TPS' partner TIL – there are only about three such specialist companies in the world.
Valparaiso's city authorities did express their initial concern, given a lack of local experience in this field, and it took around three months to get the necessary permission.
“The controlled collapse took just five days. O´Brien Demolition arrived at the terminal on September 27 to do the first on-site visit. After that, it was a question of preparing everything for the work, which took place on October 1. Everything went perfectly and the company was able to leave the terminal the same day,” says TPS.
The controlled collapse took place over eight hours, although disposal of the metal structure was undertaken by Gerday Aza and took an additional month. Gerday Aza had offered to dismantle the crane piece by piece, but this option would have taken too long.
“The process was a complete success. However, looking back, we took many safeguards that were not necessary. For example, we put up a fence to keep people out of the area, even though none of the pieces of the falling crane went there,” notes TPS.
O'Brien Demolition was also called in by APM Terminals in December 2018 to dismantle a crane recently knocked over by a ro-ro vessel in bad weather. Speaking to Port Strategy from the port, projects manager, Callum O'Brien, noted that this type of emergency is unfortunately quite common.
“We recently took down a ship-to-shore gantry crane in the Bahamas, which had been irreparably damaged by a hurricane,” he recalled, adding that the company often has to react at a moment's notice to carry out emergency demolition or dismantling.
Other than weather, emergencies are also down to human error or accidents linked to serious structural failure.
O'Brien invariably undertakes a controlled collapse of cranes, since this is usually the safest and most cost-effective method. This involves making strategic cuts to the structure, which is then pulled to the ground using tugs or reachstackers.
“It takes no more than six hours to demolish a crane using this method,” Mr O'Brien says. In contrast, using mobile cranes to dismantle a crane piece by piece can take up to six days and involves more risks, since the dismantling crew will be working over 60 metres above ground level. Terminal operators prefer not to close the quay for too long, either, since that leads to a loss of production.
“Before we offer a quotation for any works, we need a lot of information from the client and also carry out a site survey to ensure we don't encounter any nasty surprises when we arrive on site. From the information gathered, we put together a bespoke demolition/dismantling package that best suits the port's needs,” he says.
High winds are the company's greatest enemy, since O'Brien needs a good, clear day to undertake a controlled collapse. For a longer dismantling operation there needs to be at least six clear days, so this work tends to be restricted to the summer months.
“We also have to be very aware of the environmental aspects of what we do,” adds Mr O'Brien. “For example, if a gear box breaks open a large amount of oil could potentially get washed into the sea, which is why we drain oil from the crane prior to the collapse to minimise the risk of an oil spillage.”
During these types of operation a sand type material is laid on the quay to cushion the impact of the falling crane but in some cases steel is also used to protect the quay infrastructure itself.
SPECIALISTS IN THE DISMANTLING FIELD
UK-based BDB Dismantling undertakes three or four crane dismantling projects each year, usually because the crane has aged.
The other major factor is obsolescence, with three container gantry cranes at the Port of Hull recently dismantled piece by piece by BDB for this very reason.
“There appear to be very few companies prepared to dismantle redundant port cranes. This could be because dismantling work can be quite complex, particularly when a crane is old and relevant information about it unavailable,” says the company's director of estimating Carl Payne.
Asked why the company doesn't use controlled collapses, he says these can have a major impact on ground conditions, so BDB prefers to avoid them, even though its preferred method does take more time.
“There is always time pressure whenever we are called in to do work for ports. However, safety always takes priority. There are invariably unexpected delays, too, which frequently occur because of the need to prioritise vessel handling or because of high winds,” says Mr Payne.
The aforementioned Hull project involved assembling a self-propelled modular trailer on site and moving the cranes from their original berth to an off-site location for dismantling in a controlled and safe environment, where disruption to surrounding port activities was minimised. By taking this more cautious approach, little groundwork needed to be undertaken, although the ground bearing pressure does have to be known before any work starts.
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