BAYNARDS BRIDGE, SURREY

Baynards Bridge carried the now defunct Cranleigh Railway Line over a local valley on the Cotswold Edge. Surrey County Council/ May Gurney commissioned Tempo-PCE to undertake the refurbishment of the brick arch barrel bridge, which involved the rebuilding of the outer edges of the brick arch, as well as structural and waterproofing injection. Works were carried out in three stages: firstly a series of substantial brick repairs, namely the careful removal and rebuilding of the four outer rings in damaged areas, brick stitching, tie bars fitting, and repointing. The second step was a waterproofing injection: to prevent the structural injection grout being diluted by water running through the structure, an umbrella of waterproofing resin was injected into the backfill. The last phase was the strengthening injection, where a custom mix of acrylic resin and micro fine cements was injected over a staggered 250mm grid. Drill holes terminated approx. half-way into the extrados brick ring. Injection was completed at low pressure, a maximum of 3 bar, and carried out to refusal. This allowed the grout to fill all reachable void, and penetrate around fragile existing services.