Beaver Bridges provided a full turnkey package (in respect of the bridging), taking the project through the design phase, integrating health, safety, and welfare into the planning and management into these works. Careful planning of each element was the byword from the design stage through the safe removal of the existing structure and forward on to complete installation. Beaver Bridges supplied all resources including staff, machinery, equipment, tools and materials. Site-specific inductions for all site staff ensured they had the skills and competency to enable them to safely carry out their relevant tasks. Key consideration was given to the harsh salty environment which dictated extra protection and durability. This also limited access for plant equipment, ie the use of light machinery and equipment which was deemed necessary.
The Original Structure
The existing footbridge (removed) is a three span simply supported timber structure with spans of (4.5mx4.5mx2m) founded on concrete piers and bank seats. The parapets are tubular post and rail with mesh infill, with the posts bolted to the outside of the primary timber members. The overall length is around 11m with a clear width between parapets of 920mm.The structure is being replaced as it is starting to deteriorate, and maintenance is not considered to be economical.
The Replacement Structure
The footbridge is a single 11.638m span simply supported Pratt Truss Bridge using Pultruded Structural Fibre Reinforced Plastic (FRP) Sections connected by Stainless Steel components. The overall length of the bridge is 12m. The parapets are composed of 1.4m high FRP top and bottom rails with powder coated aluminium infill spindles, fixed to the main bridge truss. The internal clear width of the footbridge is 2m, with an overall width of 3.65m. The bridge is founded on 4 No. concrete free pile clusters sited at each corner of the bridge.
The new Structure Design Criteria
The bridge has been designed with a longitudinal camber of 30mm and a gap along the side edge of the deck to prevent pooling of water on the footbridge.
The approximate weight of the new structure is 3.5 tonnes.