We have been asked by customers on a number of occasions for some advice as to equipment and method choice for general site clearance and the removal of demolition material.
As an example to illustrate the problem the site location will to a certain extent determine the size of equipment and method of clearance involved. For example a large country property on an acre or more plot with good site access may utilise a 13 tonne excavator or larger for demolition and a fleet of 20 tonne capacity tipper lorries to remove material from site. A similar project in a suburban environment may require more manual labour, smaller excavators and skips or grab lorries to facilitate material removal.
We are therefore going to take just a brief look at each of the main factors involved in site clearance and try to illustrate some of the key equipment used with video clips. Our experience suggests that there are many factors to take into account in order to formulate a workable site clearance plan, resulting in each site having to be carefully assessed according to the following criteria:
Site Access – The access to the site will determine to a certain extent the maximum size of excavator and or transport vehicle that can be accommodated. Is it possible for example to remove part of the site boundary to enable access for a larger machine? Consideration needs to be given if haulage tipper lorries are to be used as minimum straight run access width is 2.75m on level ground. If high walls or pillars border the access then 3.05m is needed.
Haulage Road – If the ground conditions are poor, for example clay soils, then a haulage road or track may need to be laid in order for transport vehicles to access and exit the site in most weather conditions.
Could part of the demolition material be used to form a haulage road?
Excavators – Excavators form the main plant requirement for site work and generally the larger machine that can be used the better. Excavators are generally classed according to their weight and are usually from 3 – 13 tonne for site clearance.
Dumpers – Again may be needed according to site requirements and range from 1 tonne skip capacity machines able to load an 8 yd skip through to 3 tonne and 6 tonne capacity machines to transport material across the site for loading by grab lorry.
Tipper Lorries: Where it is possible to use in excess of a 5 tonne excavator and with large amounts of material to remove from site Tipper lorries are another option for spoil removal. The excavator will ideally build an earth ramp level with the load deck in order to quickly load the lorry. Ideally the excavator should be sized to the lorry in order to load quickly and an 8 wheeler should effectively be filled in around 15 minutes with an 8- 12 tonne excavator.
Tipper lorries are available in the following sizes:
8 wheeler – 20 tonne capacity
6 wheeler – 15 tonne capacity
4 wheeler – 10 tonne capacity
Grab Lorries – Basically a tipper lorry in the above size capacities fitted with a clamshell hydraulically operated grab. Loading time is slower than an excavator – typically 15 -30 minutes to load an 8 wheeler.
Skips: Generally uneconomic on large sites for site clearance due to cost and coordination of skip exchange and collections. The common sizes are 8, 10 & 12yd skips, with larger roll on – roll off skips in 20 yd and 40 yd sizes for green waste and light material often being used where space permits. Visit: https://www.youtube.com/watch?v=jdOH6W5DAGw
Mobile Crushing plants: Where environmental considerations such as noise and dust pollution are less of a concern then the option of recycling demolition material on site is worthy of consideration. The hire of mobile diesel driven concrete crushing equipment enables material to be crushed down to sizes ranging from 40mm to 10mm which can be reused on site for hardcore, infill etc. Mobile site crushers are available with outputs of crushed material from 6 tonnes to 80 tonnes per hour dependent on machine and material being crushed. Visit: https://www.youtube.com/watch?v=b8YbYiJbLQQ and https://www.youtube.com/watch?v=zjHKjBIyxho
Crushing buckets: Another option to consider is hiring a hydraulically operated crushing bucket for attaching to the on-site excavator. The load /crush / release material cycle time is approximately 40 seconds and outputs vary from 1- 3 tons/hr on a bucket sized to a 1.5 tonne machine to 15-30 tons/hr for a crushing bucket on a 13 tonne machine. https://www.youtube.com/watch?v=Bn-66isVtoQ
Environmental considerations – How close to the site are the neighbours? Is noise going to be a factor? Is dust going to be a factor? If environmental considerations are considerable then the option may be a combination of the above in order to minimise disturbance generally.
Cost: This is where it gets tricky. The most efficient method to employ in terms of time may not be the most cost effective in terms of budget. All the factors briefly mentioned in this article together with the availability of skilled/unskilled labour on site need to be incorporated into the overall plan in order to ensure a practical and cost effective solution.
We hope you find this brief overview interesting and informative. For more information on any of the points raised in this article please contact us – Tel: 01784 433984 or use our contact form.