RMD Kwikform’s engineering team has designed ten specialist pyramid support towers to help contractor B & K Structures construct an innovative wood and steel geodesic dome for the impressive £21m leisure centre project in Scunthorpe.
The new part Lottery and Sport England funded leisure centre, will transform the lives of local residents creating one of the UK’s most lively and interesting facilities that will complement the adjacent Central Park, which will also be refurbished as part of the scheme.
Housed within the geodesic dome pods will be a large fitness suite, a 25m swimming pool and a training pool, a dance studio and a six-court sports hall. A crèche and a café will also form part of the complex.
Erecting the structure, which once completed is self-supporting, thanks to a steel spine, was a complex task, requiring specialist systems that could provide pinpoint node support, without compromising or slowing down the erection procedure.
Tasked with connecting numerous individually fabricated steel node points to varying lengths of special Glulam engineered timber sections, (Glulam consists of planks of timber that are finger jointed to create endless boards, then pressed and glued together to form beams or columns) B & K Structures had to find a safe and workable support solution.
Having worked with RMD Kwikform on a number of previously successful projects, the B & K Structures project team made contact with RMD Kwikform engineers at the earliest design phase, to devise a practical support system that would meet the tight programme needs.
Commenting on this and the structure itself John Booth, B & K Structures contract manager said: “The really exciting part of this project is the nature of the structure that will house the new leisure centre. It is truly unique in its design, consisting of five interconnected ‘untrue’ geodesic domes to form a roof over the facility. Once completed it will look very impressive as if a number of different sized pods have been connected together.
“The core self-supporting frame is extremely intricate in design and cleverly marries the use of wooden beams and steel node point connectors to create the geodesic domes structure that is further supported by a steel spine running across the full length of the structure.
“But it was the assembly of this core that created the most issues onsite. Initially we thought we were going to have to prop up each steel node point in order to ensure the frame was adequately supported. This would have created an extremely difficult environment to work in, as mobile cherry pickers and cranes had to be used to safely lift the wooden beams, into place.
“Also due to each ‘node point’ being individually fabricated with connection points at different angles, maneuvering and slotting beams into place on what was a giant dome jigsaw, required two members of the erection team and a crane operator – a total of three mobile pieces of plant.
“So reducing the number of support structures within the tight confines of the dome was essential. It was here by working with RMD Kwikform engineers that we were able to model the erection sequence including the horizontal, vertical and tangential loads placed upon the structure at different points.
By understanding the pressures and moments these loads would exert on the dome we were able to determine where to place support structures, how they would be loaded and what we needed to do to build in additional strength in order to reduce the number we required.”
In order to meet B & K Structures needs, RMD Kwikform engineers worked hand in hand with the B & K Structures team to design a special pyramid topped support structure, using specially fabricated parts mounted on a Rapishor tower. This design ultimately reduced the original need to support up to 168 different node points at one time, enabling the structure to be supported at just 10 points at any one time.
RMD Kwikform’s Chris Holland explains: “Flexibility was the key to the design of the system. In order to achieve the level of support required, we had to make sure were able to designed a system that could be altered and adjusted to support node points at different angles and heights.
“This was achieved through the design and fabrication of an adjustable pyramid shaped head support that could be mounted onto Rapidshor shoring towers. Because Rapidshor is one of our core products we could reduce the overall cost of the system, whilst also allowing B & K structures to achieve the very precise heights required for each tower.
Due to the strength of Rapidshor the towers themselves, we were able to use just a small amount of space, while providing enough strength and support for the roof to rest on. The tower systems were able to take loads of up to 20 tons from the steel node point, through the pyramid assembly, tower legs and into the ground below, without damaging the wooden sections of the structure,” Chris added.
Whilst the core structure was erected in waves using the ten RMD Kwikform Rapidshor pyramid support structures, which were moved back as the dome took shape, cedar clad and insulated prefabricated sections were installed by a separate team, to allow for the roof structure to be assembled and sealed.
Additional information on Glulam Beams
The engineered timber beams used in the project are known as European Whitewood (Spruce) Glulam beams. Glulam consists of planks of timber that are finger jointed to create endless boards, then pressed and glued together to form beams or columns. This allows the Spruce beams some flexibility and prevents them from warping whereas a single piece of timber would be prone to warping