Demolition heights

11 April 2008

Urban regeneration across Europe is driving the development of the specialist demolition techniques and equipment that are required to remove old or outdated structures to make way for the new. High-rise or large structures can be brought down using explosives, but in the confined spaces of many of today's job sites, this approach is not practical.

As a result, the development of the high reach demolition excavator is moving at pace, with just about every full line manufacturer now offering a number of such models. They tend to keep to the volume end of this market sector, however, and their machines generally do not carry booms taller than 40 m.

If you want something bigger, there are a number of specialists around Europe who meet the demands for machines with working heights over the 40 m mark, and their offerings are growing in height as the market demands more machines that can reach high.

As an example, Ipswich, UK-based Kocurek recently delivered a modified Hitachi EC1250 fitted with a 64 m telescopic boom to UK contractor 777 Demolition – telescopic technology forms the basis for most ultra-high reach rigs, since it minimises power requirements for raising and lowering functions.

Similar in appearance to mobile crane telescopic booms, these have pushed the envelope of vertical reach well above the 50 m mark, which was about the limit achieved using multi-piece articulating (but non-telescopic) booms.

By far the biggest of the new breed of demolition 'machines“ is the 90 m demolition 'crane“ being built by Rusch in Amsterdam, the Netherlands, for specialist high reach contractor Euro Demolition.

Based around a Cat 5110B mining shovel and a three stage telescopic boom, this giant machine is due to be completed by April 2008. But it is not just the height of this machine that is impressive, it is the weight of tool that the machine can carry. At full height it will carry a six tonne tool, and at 80 m an immense 12 tonnes. This kind of reach and tool weight would have been considered impossible just a few years ago, and shows the kind of engineering expertise that is being applied to the sector as well as amply illustrating two of the main drivers for demolition equipment – greater working height allied to more powerful demolition attachments.

Boom Ends

Demolition projects in urban locations naturally place requirements on contractors to exercise ever greater care of environmental impacts and, of equal importance, to minimise any potential adverse impact on the people working or living in proximity to the site. This is fuelling the demand for attachments that can perform demolition work in relative silence. Thus, the hydraulic breaker, long the standard tool of choice, is increasingly being replaced by specially designed demolition attachments, such as crushers, pulverisers and multi-tool systems that have several interchangeable jaw sets.

The changing nature of the buildings now being demolished is driving the development of these tools. Increasingly, better quality concrete with stronger reinforcement is being encountered.

As a result, tool manufacturers now are seeing a growing demand for larger, more powerful and therefore heavier demolition attachments for use on even the tallest high reach equipment, which in the past were expected to only carry tools weighing up to 2,5 tonnes.

As a result, some impressively large attachments are being designed and delivered to customers around Europe, such as Trevi Benne's 21 tonne FR200 rotating pulveriser, delivered to a Spanish customer, and Mantovanibenne's 11 tonne rotating pulveriser, the largest the company has ever produced. This unit will ultimately end up on the end of the 90 m high reach demolition “crane“ mentioned above.

But there is another approach to providing greater power. New designs may provide more power at a lower weight and materials such as aluminium and new Hardox steels may well play their part, and the demolition attachment of 2017 may appear totally different to models available today.

Recycling Drive

Recycling is not new to the demolition industry, with many contractors having traditionally found ways to re-use or exploit the waste that results from their activities. However, the drive is on at an EU and national government level across the continent to achieve high recycling rates as part of the development of a more sustainable construction industry. Today's demolition contractors are playing their part, with recycling rates of 75% to 80% being typically achieved.

Once separated, materials like concrete, bricks and blocks can be crushed and sized for use as aggregates. Although there are strong similarities between the crushing and screening equipment used for virgin aggregates production and recycling demolition waste, there are a few key differences.

First, equipment used for recycling has to be mobile. Aggregates tend to be crushed on site or nearby, so the flexibility that mobile machines brings is essential.

Second, the crushers and screens used in recycling are often at the smaller end of the scale. They have to be easy to transport on and off site, and not take up too much space while they are working. Another reason that recycling crushers tend to be smaller is that they do not usually have to deal with the high volumes of materials that quarries do.

Like the demolition sector in general, the market for recycling equipment has come a long way in the last 10 years or so, driven in part by the increased impetus to recycle demolition waste due to laws and taxes. The growth in the smaller end of the mobile crushing and screening sector has elevated it from something of a niche market, served by relatively small regional players, to a genuine multi-national business.

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