In November 2018 RAB replaced four expansion joints at Upper Boat Bridge which had already previously, and very recently, failed twice. The client had originally specified a Type 6 EMR metal runner joint, which is expensive and time consuming to install but offers excellent longevity and movement capabilities. After discussions with RAB’s joint design team, it was agreed that the innovative Wabo®Air Inflated Systemcould meet all the requirements, whilst being considerably more cost effective and quicker to install. An important advantage of this system is that due to the seal being air inflated and epoxy bonded, it allows for much greater movement beyond its installation width, unlike traditional compression solutions.
The final solution included the use of Wabo®Crete II nosings and Wabo®Air Inflated Seals on the joints. The Wabo®Air Inflated Joint system offers incredible movement capabilities for its size and utilises an innovative installation procedure that requires the seal to be inflated within the joint gap itself. This ensures very high adhesion with the epoxy based adhesives, ensuring an outstanding, long term, low maintenance solution.
Work began with the existing joint sealant being removed along with 130mm on either side of the joint gap, down to the deck. All debris was removed from the joint gap and the deck was then cleaned and prepared. Concrete repairs were carried out before new nosings were created using Wabo®Crete II leaving a 40mm gap.
After sufficient time was left for curing, a grinder was used to create a chamfer on each nosing edge. The Air Inflated Seals were then ready to be installed and tied into the footpaths.
The works were undertaken over a number of nights with a closure to one side of the bridge each night.