As good as new

Service life extension projects (SLEPs) are a growing activity for crane repair companies (and for manufacturers). Take US company Wheco Corp as an example. Jay Shiffler, vice president and director of business operations told IC, “Wheco has been doing SLEP projects for more than 25 years. The concept is to develop a specific and cost effective scope of work that will extend the working and revenue generating life of a piece of equipment.”

A good example, Shiffler explains, is conventional lattice boom truck cranes. Limited availability and high replacement costs make them excellent candidates for a SLEP, Shiffler says. As an example, Wheco recently carried out SLEPs on two Link-Belt HC 238A lattice truck cranes. Both were 20 years old and were part of a large and heavily used crane rental fleet. A scope of work, short of complete restoration, was created by Wheco to extend the working life of the machines by between 7 and 10 years, with the restoration cost evaluated against the expected revenue stream and operating expenses. The company is carrying out similar work for the same customer on two more units.

Rough terrain cranes are also good candidates for SLEP work, Shiffler says, “Often considered disposable cranes, rough terrains can be simple and very cost effective to SLEP. Again, a cost effective scope of work can be measured against the potential revenue stream and operating expenses to determine the feasibility of a SLEP.”

When it comes to repairing accident damage several factors have to be taken into account, Shiffler says, but the decision to repair or replace major structural components and parts, or the entire unit, is ultimately a financial consideration. These are based on the crane's market value, insurance coverage, overall condition of the unit, cost of repair over replacement, unit downtime, expected service life after repair, expected salvage value and whether a salvage buyer would part it out or have it repaired.

The most frequently damaged cranes appear to be mobile hydraulic truck, all terrain and rough terrains, according to Shiffler. Rough terrains in the US are typically bare rented, which makes them more vulnerable, and the mobile hydraulics have a high utilisation rate, travelling the US highway network between jobs. Shiffler says accidents with conventional crawlers do happen, but less often.

Age old repair

Equipment age does not affect vulnerability to accidents, but it has an effect when determining the feasibility of repairing or replacing parts, components or the entire unit. Boom and jib repairs are the most common type of work resulting from accidents or misuse, but bent and twisted frames and cab damage resulting from accidents is common.

But what about quality? All repairs done by Wheco, for example, comply with OSHA, Cal-OSHA, ANSI and AWS standards, and the company guarantees that its repairs are inspected and certified by an independent third-party crane certifier. Documentation is provided for all engineering repairs, including engineering, material analysis, welding procedure specifications and test records, and NDS test reports.

Dutch company Avezaat is another company seeing increased volumes of repair work for cranes around the world. There are two reasons behind this growth, according to Bert Avezaat - a trend for equipment life to be extended, and increasingly stringent safety and certification requirements.

Virtually every crane type and brand is represented, with lift capacities from 2.5 to 1,000 tonnes. In volume terms the majority of repairs the company carries out are on lattice and telescopic booms on mobile cranes, dating from 2005 models all the way back to 1930. The majority of the company's work involves the replacement of structural elements for boom lattices and either manufacturing new parts, or delivering from stock, from connections to top pieces, to breeches and jibs. Avezaat also repairs, and manufactures parts, for telescopic booms.

Another Dutch company, Rusch Crane Repair, specializes in repairing telescopic and lattice booms. The company uses an ultrasonic impact treatment (UIT) technique, developed in Russia and further refined in the US, to increase the fatigue strength of booms by up to 800%. Both repaired and new booms have to be 'directed'. This directioning (forcing into shape) results in internal tensile stresses that not only shorten the lifespan of the boom but also limit the maximum load. The company claims the UIT converts the tensile stress into a moderate compression stress, thus increasing the fatigue strength.

Work at the factory

Where manufacturers are concerned, the bulk of refurbishment and repair is carried out on trade-ins. In Liebherr's case, work on used equipment ranges from just a workshop inspection through to full reconditioning with warranty. The company has workshops in Erlangen, Oberhausen and Alt-Bork in Germany, while subsidiary companies in other countries also have their own repair facilities (the latest in Dubai and Houston, Texas).

When carrying out a full overhaul, all crane assemblies are overhauled or replaced with new or rebuilt parts, with inspection and testing carried out as it would be for a new crane, the company says. Work can also include repainting, new logos and new tyres. At the time of writing Liebherr had few used cranes in stock due to strong demand.

Tadano Faun also runs a dedicated refurbishment and repair workshop that can handle all levels of work, from inspection through total rebuild, selling trade-ins from its home German market around the world, with heavy demand currently being experienced from the Middle East. Machines can vary from 2 to 15 years old, and are supplied with warranties for all new parts, the work carried out and, in some cases, the full crane, depending on age.

On the water

Cranes working on fixed offshore oil and gas installations are frequently refurbished and upgraded, particularly in the North Sea oil fields. Once again, service life extension is the name of the game. Many oil fields are operating well beyond their original expected extraction life as techniques have improved and economic factors make continued operation more viable.

In most cases, cost dictates that refurbishment is chosen over replacement. Down time on the installation and the cost of hiring a floating crane to remove the old unit and replace it with the new one have to be taken into account, added to the cost of the new unit itself.

Liebherr's offshore crane division recently completed upgrades on 20 cranes on a North Sea oil complex. Typical of the type of work it does is the recent overhaul of a BOS 125/1250, built in 1984 for SBM Installer SA and fitted to a diving support vessel operating off the Congo, Africa. The crane was fully overhauled, including fitting a new operator cab with noise protection and additional air conditioning, installation of a CANbus control system and a new 400 kW Liebherr V8 engine. The boom was dismantled, shot blasted, repainted and then reassembled. Finally, the winches were overhauled.

Whether a mobile, tower or offshore unit, there is no doubt that refurbished and repaired cranes can offer an opportunity for lifting at reduced cost, and a greater return on the initial investment through a longer service life.