Crane platform design requires return to school
PDMA Consulting Engineers were recently engaged by Arthur M Griffiths and Son Limited to design a crane platform as part of the construction project for Huntingtree Primary School in Halesowen.
The Wolverhampton-based construction company is constructing a single storey, steel framed building, incorporating precast concrete floor units. Installation of the floor units requires a 100 tonne crane working from a suitable and safe platform for the lifts.
All works are being undertaken in a live working educational environment, which places additional demands on the need for the highest health and safety standards on site.
This was a project close to home for PDMA Director Paul Markham, who commented: “Huntingtree was my first school and this was the first time in almost 50 years that I had returned. This time I was there in a professional capacity with sleeves rolled up.
“Although there was a site investigation report available, I prefer to make my own assessments of the site on which the crane was to be located, especially as it had moved from its intended position at the start of the project.
“In the crane’s proposed new location, the upper levels of the ground had been disturbed and weathered, so we had an excavator scrape off the top few hundred millimetres, to allow me access to the clay beneath.
“Combining a few simple field identification techniques and years of experience ensured the strength of the clay could be easily assessed.
“Despite all the modern technology available to use, hands-on in situations like this, pays dividends. Depending on how hard the clay is to indent with the thumb or squeeze in the hand, allows an engineer to put numbers to the strength, which can be used in the design of the crane platform.”
The calculations indicated a platform 225m2 would be required, constructed to a depth of 0.5m with approximately 200 tonnes of 6F2 aggregate. This was compacted in accordance with the Highways England Design Manual for Roads and Bridges, to guarantee a stable base for the crane lifts.
Markham concludes: “The platform was designed to take advantage of material on site to save the construction firm, time and money – an essential aspect of the PDMA offering; designing value into every project, whether it’s temporary works or permanent features.”