The edge of the envelope - today's demolition excavators

Twenty years ago, high reach demolition excavators were a rare sight, and even 10 years ago, they were still unusual. Today they are almost commonplace in Europe and are growing in popularity around the world.
Indeed, the high reach concept does appear to be gathering greater acceptance in North America. Acording to Volvo's North American segment manager-demolition, Walter Reeves: "In North America, we see the demand for high reach increasing. As funds are released, the work is following quickly and this will drive our business to new levels of demand."
This is especially true in urban environments where space is at a premium and demolition has to be carried out in a controlled manner, often under tight noise and dust emission constraints.
Until just a few years ago, the primary driver for these machines was height but this has changed in recent years. Some contractors still want the highest, but many others would ideally opt for a balance of height against performance. By this, they mean the biggest, most powerful possible tool at the optimum height - usually said to be a reach of between 25 and 30 m (80-100 ft), with tool weights from 4 to 7 tonnes.
Where North America is concerned, Walter said: "There is some desire to go higher in our region but this business is still in its infancy - as acceptance grows, high will come quickly. Where tool size is concerned, there are always questions about bigger tools for our high reaches but we need as an industry to continue with safe working practices."
Most OEMs offer a range of high reach demolition excavators in their product line using their base carriers modified for the role with, usually, an extending undercarriage to increase stability, heavy duty guarding on the cab and undercarriage, and, especially where the larger machines are concerned, a tilting cab that allows a clearer view of the business end of the machine - the tool at the end of the boom. Frequently they also feature a coupling system that allows relatively quick boom change-overs to allow for flexibility in use. However, the one common limiting factor most of these machines feature are tool weights seldom over 2.5 tonnes, including any quick tool coupling system fitted on the end of the boom.
Given the current economic climate, allied to the latest engine emission legislation, the OEMs in recent months have been concentrating more on their standard models, re-engining them to meet Stage IIIB/Tier 4 Interim emission requirements. Given also the fact that many had only recently completed their full line of high reaches, things have been quiet where OEM produced demolition machines are concerned.
Anecdotal evidence suggests that 2007 saw the high point in demand for high reach machines, demand fell in 2008 and the low point in unit sales was reached in 2009. Since then, it would appear that there has been a steady growth in demand for full line manufacturers' machines.
The big show of the year is usually where new high reaches are put on show for the first time - 2012 will see the Intermat event in Paris being the largest construction show of the year. As such, it will be the venue for numerous new Stage IIIB/Tier 4 Interim compliant excavators. Given the development times required for high reach versions, it may be some time before we see high reach versions of these machines (although D&Ri understands that there may well be one or two gracing the Paris exhibition ground).
Komatsu is one of the leading high reach providers, and product specialist Michael Atkinson confirmed this when he told D&Ri: "At Intermat, we will show the PC240LC-10 in demolition specification. This comes with heavy duty protection and straight boom options. The high reach versions of the new -10 models do not have a launch date at this time due to the considerable deveopment work required for such specialised machines."
The main exception to this is Caterpillar. As previously reported, Caterpillar has teamed up with boom specialists on both sides of the Atlantic to produce its next generation high reaches. In Europe, a Vensys Group subsidiary company has been formed that takes standard Cat carriers and modifies them for the demolition role (see D&Ri, Mar-Apr 2010, p8). The Demlone 50 introduced at that time was followed by the 33 m (109 ft) Demlone 70 introduced at the beginning of 2011, with the final 43 m (141 ft) Demlone 100 expected to appear by the end of this year.
In mid-2011, the first North American equivalent, the 70 tonne Apex 70, made its first appearance. For North America, Caterpillar has teamed up with Jewell Equipment, the leading North American boom specialist, to form a similar arrangement as in Europe. The Apex 70 will be followed by the 100 tonne Apex 100 and then, depending on demand, the 50 tonne Apex 50, with the first two models expected to be the most popular in the North American marketplace. These three machines will offer working heights broadly similar to their European counterparts.

Quick connect

Talking about quick hitches, until just a few years ago the trend was for the favourite tool at the end of a high reach's boom to be a multi-tool - a single tool that can act as a crusher, shear and pulveriser, depending on the jaw set fitted.
With the advent of reliable and efficient quick hitches, these tools have lost ground, with contractors increasingly providing a number of tools for use on a single machine - a breaker, a crusher, a pulveriser and a shear - as appropriate.
When asked, the general take on this is: "why should we use a single tool that only does three jobs at 70% efficiency when 100% efficiency can be obtained with three separate tools that can be changed over in a matter of minutes".
Along with Japanese manufacturers producing equipment for their home market (there are ongoing rumours of a 100 m high reach under development there), European manufacturers are at the forefront of developments in high reach equipment for the demolition sector.
But it is not from the most familiar names. While the full line manufacturers, such as Caterpillar, Hitachi, Liebherr, Komatsu and Volvo, may well offer extensive arrays of demolition rigs, they rarely offer machines with more than 40 m reach that are never capable of carrying tools greater than 2.5 tonnes in weight. It is above these limits that European specialists take over, and whose heavyweight machines have started work on site.
The latest example will begin testing in early 2012 and could almost be described as a Swiss Army knife of the high reach sector. Designated the RS4500 by its designer, Rusch Special Products in the Netherlands, this is machine is (loosely) based on a Hitachi 870 carrier, although you would be pushed to recognise that fact. Carrying full working gear, the result is a 180+ tonne monster with a maximum 55m reach.
It is like a Swiss Army knife because the machine has been designed to self-assemble on site and carry three different booms to suit the application. These booms also allow it to carry a range of tool weights to conduct the full gamut of demolition activities on a building, right down to heavy duty foundation removal.
A three-stage telescopic boom can carry 5 tonnes to 55m - do not extend the third telescopic stage and it can carry 10 tonnes to 40m. A four-piece articulated boom can also carry a 5 tonne tool - drop the fourth stage and mount a tool direct to the third stage and again a 10 tonne tool can be carried. Finally, a heavy duty dig arm can reach 20m below ground level carrying a heavy duty bucket to tear out underground structures (see www.khl.com/demolition for a video of the concept).
With this machine, Rusch has gone for a combination of tool weight and reach height, and another has followed the same development path. The UK's Kocurek Excavators, working closely with customer Heavy Decom International (HDI), produced a 200 tonne-plus machine also based on a Hitachi carrier at the beginning of 2011, this time an EX1200.
Kocurek's customer knew exactly what it wanted and the machine again is something special. It is able to carry a 25 tonne shear to 20m and a 15 tonne shear to 30m, based on a three-section articulating boom. Kocurek also provided a fly dipper to take the final height to 35m with an 8 tonne attachment.
According to Hardy Worsey, joint founder of HDI with Chris Hinett, "After many years' experience using large high reach around Europe, we had a pretty clear idea of what we needed. We favoured using the Hitachi carrier as a basis for the machine - we have used other high reaches using that carrier, it is reliable, strong and above all, its hydraulics are not computer-controlled. We believe in keeping it simple."
Given the size and capabilities of the machine, simple is, perhaps, not a relevant word.

Reaching high

Some still go for height and accept the limitations in tool size that this brings. Kocurek recently handed over the highest reaching machine in the UK, and probably the largest currently working in the world (the record breaking 90m high reach from Rusch is currently being modified and is not actually working on site).
This is a modified Liebherr 984C currently being used by customer Technical Demolition Services on the demolition of residential tower blocks in Scotland's second city, Glasgow.
At a maximum reach of 67 m with an extended dipper arm, this machine can carry only a 1.5 tonne tool. With a standard dipper and a height of 62 m, this increases to 2 tonnes. Given the application, these tools weights are perfectly adequate, but nevertheless fall well short of the "wish-list" weight, illustrating the mantra that height is not everything.