We were commissioned to perform design check calculations on a suspended access platform for the Northern Spire Bridge in Sunderland, UK, for our client Apollo Cradles. The 27m x 12m platform, which was suspended from the existing beams of the bridge, provided a safe working space at height for the maintenance and repair of the bridge.
The lightweight platform was constructed from 6 aluminium X-beam boxes, with a diameter of 0.75m, which were evenly distributed along the 12m width of the platform, and extended 27m between the supports of the bridge. A further single X-beam extension was placed around the perimeter of the platform to support the handrailing.
The structure of the platform was completed using scaffold components which tied together the X-beam boxes, and 18mm thick buffalo boards were placed over the platform to provide a safe, lightweight working surface.
We performed design check calculations on each element of the structure using STRAP Analysis Software, including calculating member capacities under different loading scenarios, factoring in local wind conditions due to the external location of the platform. The checks determined a safe working load of 0.75T for the platform, including people, tools and equipment.