Concrete Repairs, Migrating Corrosion Inhibitors, Coatings and Parapet upgrades


Clifton Bridge in York is a six span structure with precast deck beams supported on insitu RC piers, abutments & wingwalls spanning the River Ouse.  The river, which carries water from the Yorkshire Dales, is liable to extreme variations in level

 Following an inspection it was noted that the existing coating system was failing, areas of spalling concrete were evident and the parapet railing system was due to be upgraded.

 Following a competitive tendering process Topbond were appointed to carry out the refurbishment works.  To gain access to the midspan bridge soffit and piers Topbond provided their own pontoons off which a birdcage scaffolding was built.  For the remaining spans scaffolding was supported off the piers and river banks where available.

 Using a combination of pressurised superheated steam and grit blasting the existing coatings were removed allowing a defect survey to be carried out.  The repairs were undertaken using a combination of percussive breakouts and patch repairs to high water jetting breakout and sprayed repairs.

  On completion of the works  approximately 5000 Margel DCI 580T microporous cartridges containing the blended components of Migrating Vapour Phased Corrosion Inhibitors (MVPCI's or VPI's for short) offering fast, medium and long-term protection were installed on a diamond grid pattern at a depth of 100mm below the concrete surface. This is the largest use of Margel tablet on a bridge refurbishment scheme.  An anticarbonation coating, together with an anti-graffiti coating was then applied to the bridge.

 1.4m high aluminium parapets were installed to replace the original steel parapets and new lights were fixed to them.

 Topbond are approved installers of QED's Margel VPI