The three bridges supporting the A55 through the Talardy Interchange were built in 1970. All three bridges have weak bridge deck ends and are in poor condition. Concrete repairs are to be carried out and strengthening steelwork installed. If the bridges aren’t strengthened heavy vehicles would soon need to be diverted off the A55 on to local roads.
Once the strengthening has been done the carriageway is to be resurfaced. This was last replaced in 2010 and is at the end of its life. At the same time the expansion joints at the end of each bridge are being replaced.
The works are programmed to take 11 weeks. Contractors will be working 24 hours a day seven days a week to ensure that the works are completed as quickly as possible. Traffic Management will be in place on the A55 from Mondays to Fridays for just 6 weeks, from the 22nd September until the 23rd October then from the 9th November until the 17th November.
After the works start and concrete is removed the condition of the bridge will become clearer. We have allowed one week of time in our programme for possible unforeseeable conditions should conditions be worse than expected.
There are activities within the works which require dry weather and materials which require minimum temperatures to be installed; the concrete repairs we are undertaking use special products to harden quickly but at low temperatures they take a lot longer to gain strength. We have given the timing of this project much consideration and we believe we have picked the optimal compromise between traffic flows and weather requirements.
Weak and damaged concrete is being removed from the underside of the bridge decks. Fast setting concrete is being used for repairs which needs time to become strong enough to support the weight of vehicles on the road above. The areas of the bridge immediately above the repair areas need to be kept free from traffic loading whilst this work is carried out.
Both the slip roads being closed are supported by a bridge over the River Elwy. We need to undertake the same repairs to these bridges as the ones supporting the main A55. We also need to use these slip roads to gain access to the underside of the main A55 bridge so we can keep a lane running through the junction on the A55 as much as possible.
There will be periods, such as when materials are curing where it appears not much work is being undertaken. These periods are required to allow certain materials like concrete and resin to achieve the required engineering properties. The programme is thoroughly analysed to see what other activities can be undertaken during these periods to ensure the work is completed as quickly as possible.
Under the bridges scaffold will be enclosed with sheeting to prevent debris from the concrete demolition escaping. Works will be continuing out of sight in these enclosed areas once the concrete repairs are done to fit strengthening steelwork and paint the ends of the steel beams.
There are several reasons why the merge-in queues could be longer than usual; it may be that there is simply a greater volume of traffic at that time. Or there may have been an accident or someone has broken down in the queue.
With any construction project, there is a certain amount of noise emission that cannot be avoided. However, most of the noisier activities have been programmed to be undertaken during the day. We also do not envisage the noise levels to be significantly increased from that of a busy dual carriageway.
The alternative local traffic routes are unsuitable for use as diversion routes when traffic flows are high during the day. Drivers who leave the A55 to avoid queues will be delayed more due to the congestion they cause on local traffic routes.