S H Structures Ltd
S H Structures Ltd
The Helix Trust
The two 30m high equine sculptures known as the Kelpies sit either side of a recently constructed lock on the Forth & Clyde Canal forming the centrepiece of The Helix in Falkirk.
Known as ‘head up’ and ‘head down’ during construction, because of their different postures, The Kelpies have quickly become a major Scottish tourist attraction and a highly visible signpost for a large regeneration scheme.
Client partners, Falkirk Council and Scottish Canals were keen to include a major piece of public art within this community-based parkland scheme, and in 2006 they approached sculptor Andy Scott.
Already well known for his equine sculptures, Mr Scott presented sketches of a proposal for two horse heads which would sit alongside the canal. At around 30m high, the form and scale of Mr Scott’s vision soon gained the interest of the client.
To provide something tangible for the client to relate to, he produced a pair of tenth scale models (maquettes) of the proposed works, which led to a commission to produce a second set of maquettes upon which the final full size work would be based. These new models were fundamental in securing the Big Lottery Funding required to allow the project to move forward.
Mr Scott normally undertakes the manufacture of his pieces of public art himself, however creating two 30m high heads required a different approach. While still being works of art, they needed to be designed to withstand the various forces to which they will be subjected and it was at this stage that consulting engineer Atkins was brought in to develop a working design that could be used as the basis for the procurement process.
Atkins’ approach was to scan the second set of maquettes to create a surface model that would maintain Mr Scott’s artistic intent. The company developed a working structural solution for the frames that would support the ‘skin’ of the two heads and be the basis for the tender process. Having suggested in their bid that a value engineered scheme could be developed based upon a revised internal structure, S H Structures were invited by the client to provide further details of their alternative scheme.
S H Structures appointed consultants Jacobs to develop their outline proposal and the resulting design produced savings in excess of £750,000, allowing the project to get back on track. In June 2012 S H Structures were awarded the contract as principal contractor on a design and build basis.
The value engineered solution was to create a structural tubular frame which would closely follow the internal surface of the skin. Working from the Atkins model, the team imported files and developed a structure that was based around two braced triangular trusses which were interconnected by braced in-plane CHS frames to form an efficient and stiff primary structure. A secondary frame of smaller CHS rails carried the brackets that provided the thousands of fixing points for the external skin.
A detailed 3D model of the two heads was developed using Tekla software. This BIM approach allowed all of the project stakeholders including the sculptor, client and the lighting designers to share and exchange files and snapshots.
S H Structures carried out as much assembly work as possible at its Yorkshire facility, with members being fabricated into large sub-assemblies that were all trial erected before being delivered to site. The sculpture’s skin is formed from stainless steel panels which were cold formed onto the thousands of individual brackets of the structure insitu.
The five month installation programme started on site in June 2013. Work started initially on the ‘head down’ Kelpie and after a few weeks a second erection team started work on the ‘head up’ sculpture.
It was at this point that all of the trial assemblies and dimensional controls carried out in the works paid dividends. With sections already matched and checked, the two structures quickly took shape as all of the assemblies fitted perfectly, which helped the project to complete on time.
Two shimmering steel horses heads, fully 30m high, required considerable engineering finesse to realise the sculptor’s vision. A tubular steel frame supports this most complex and delicate sculptural form.
Recognised internationally as probably the finest equine public artwork in the world, The Kelpies attract global visitors to Falkirk.