Solution
Due to the tree preservation order in the area, it was essential that both the pitch of the roof and the size of the timbers required were taken into account when designing the roof. Taking into consideration the large span of the project, we therefore suggested a scissor truss as opposed to a raised tie truss to achieve their desired vaulted effect.
The clients had originally approved the scheme based on a steel portal frame system. However, a substrata survey (an analysis of the foundations) revealed the point loadings of the frame would have been too considerable for the portal frame system, due to the large spans and vaulted effect required on this project. Our designers were instead able to offer the solution they required using roof trusses, which the customer previously thought wouldn’t be viable.
Our truss solution catered for their large span whilst counteracting the great deal of pressure that the point loadings placed on the walls. We achieved this by recommending that the client use Glide Shoes. Glide Shoes were an invaluable resource in this circumstance as they allowed for a secure fixing and horizontal movement between the scissor trusses and the wallplate, therefore reducing the amount of loading exerted upon the walls. They were used on both ends of the scissor trusses and provided up to 26mm of lateral movement without compromising the resistance to uplift.
Results
Our Operations Director, Eric Meacock, carried out multiple site visits on request of the client. One of the members of our design team, Rob Meacock, made several revisions to adapt the design to the client’s requirements.
The client was able to effectively explore a variety of options that suited the budget allocated to the project, including attic trusses and storage areas. After this period, the client came to a final decision on an option we supplied that would cater for the large span of the trusses at just over 10.7 metres. All plans and approvals were made over the busy Christmas period where the clients took advantage of our 5-day delivery service to ensure timely delivery.
During the project we worked closely with AECOM the appointed structural engineers to produce special structural connections to tie the trusses to the buildings and to each other. We provided detailed designs and erection stage plans that were delivered to site with the trusses to ensure ease of assembly.
