An existing timber framed canopy, with a ply deck and felt finish, was considered structurally unsound and dangerous to access the deck for maintenance.
As part of re-roofing works being undertaken throughout the school it was decided to replace the existing canopy.
A plan of the proposed canopy, measuring approximately 7m x 30m, was provided by Capital PCC Architectural Team. The design brief for the new canopy was to have support posts along the outer edge only (to maintain clear access routes), had to safely support maintenance access on the deck, be reasonably inexpensive but most of all be functional.
An initial design comprised a steel frame structure (eg. posts and beams) supporting timber joists and ply deck. The frame was analysed using specialist 3D design software to check that deflections and sway were within acceptable limits.
Following costing by a Contractor a value engineering exercise was undertaken to reduce the cost. The plan area of the canopy was reduced to 5m x 30m and flitch beams were used instead of steel beams. This resulted in a reduced cost but due to available budgets a decision was made to increase the canopy size.
A final re-design was undertaken which increased the plan area to 7m x 30m using flitch beams. Stability of the frame was achieved by the use of bolted post base plates and bespoke metal brackets at beam/post junctions.