Agenda item

A472 Viaduct

To receive a Notice of Question from Councillor Richard Thomas (Leader of the Opposition).


Question by Councillor Richard Thomas, Leader of the Opposition


‘Would the Leader of the Council please explain why there has been such an extraordinary delay in making repairs to the A472 Viaduct at its junction with the A470 in Quakes Yard.  I understand that there is a joint responsibility for this Bridge with Rhondda Cynon Taf County Borough Council but also that the part funding for the repair to be paid by this Council was agreed and within budget from April of this year’.


Response by Councillor B Toomey, Leader of the Council


As a cross border structure the Fiddler’s Elbow Viaduct is jointly owned by MTCBC and RCT. Within this arrangement MTCBC has sole responsibility for the carrying out the requisite inspections but the cost of any repair works is shared equally between both Authorities.


As everyone is aware some of the eight expansion joints within the bridge deck started to display signs of failure back in February 2014.


Following initial meetings between engineering staff from both authorities, information reports were prepared to brief Members of the issues and the estimated costs of replacement, which at that time was thought to be in the order of £1m. This estimate was based on information received from the German company responsible for the manufacture of the original joints. The latest estimate including all design, accommodation work (traffic management) and supervision cost is in the region of £1.9m. This will be split equally between us and RCT.


Further meetings between engineers from both authorities to discuss options resulted in RCT commissioning Capita Glamorgan to investigate replacing the joints with a potentially cheaper alternative.


Whilst it was evident that some of the joints had or were about to fail the precise nature of the failure was unclear. In order to stablish the mechanism of failure a CCTV survey of the joints was completed over the August Bank Holiday weekend of 2014. This operation enabled the engineering team to gauge the effectiveness of the traffic diversions that were expected to be used during the main contract, when the bridge was likely to be closed to some of the traffic for up to 5 months. As a result of this “dry run” a meeting was held with WG’s Trunk Road Managers to discuss the potential impact that the works were going to have on the A470. This meeting concluded that in order to minimise the impact on the heavily trafficked trunk road it would be preferable to priorities traffic moving west-east across the viaduct i.e. all traffic leaving the A470 would be unaffected by the works.


This decision resulted in Capita receiving a further commission to undertake a feasibility report and subsequently a detailed assessment of the impact of diverting east bound traffic over the west bound deck and the potential impacts of diverting all West bound traffic throughout the duration of the works.


The subsequent road safety audit of this option highlighted potential issues at the junction from the A4054 onto the existing A470 slip road south of Ty Trevithick. It was anticipated that traffic heading South would attempt to turn right to join the A470 at this point resulting in delays and potential collisions This again resulted in Capita being asked to look at options to enable southbound traffic to be able to turn safely and enable the majority of light vehicles to join the A470 at the earliest opportunity. Other provisions will be provided for HGV’s.


All of this complex yet vital preparatory work was undertaken by Capita as neither RCT nor MTCBC had the necessary resources / capacity to complete in house. This was done concurrently with the preparation of the contract documentation, bat / ecological surveys, noise surveys and the subsequent reports associated with each.


Because of the complexity of the scheme the tender period which is programmed to commence at the end of this month will allow 6 weeks for their return. Given that we will be approaching the Christmas break a further 2 / 3 weeks has been programmed for their assessment with a view to appointing a contractor sometime early in January.


The manufacturers of the replacement joints (there are 2 potential suppliers) have indicated that the lead time from confirmation of the order to delivery on site will be a minimum of 3 months which means that if ordered in mid-January the joints are unlikely arrive on site until mid-April.


It is anticipated that the installation works will take a further 4 to 5 months. The traffic diversions for west bound vehicles will inevitably increase traffic flows along the A4054 and it is anticipated that this will have a significant impact on all the villages between Fiddler’s Elbow Roundabout and Pentrebach. In order to minimise the level of disruption there is a consensus within the Engineering Team, that if necessary, it would be preferable to delay the start of the work by a further month or so to ensure that we take full advantage of the reduced traffic flows that occur towards the end of the Summer Term and throughout the Summer Holidays. This will also allow the works to be undertaken during a period of maximum daylight and hopefully dry weather. 



Supporting documents:


a to z of services
A B C D E F G H I J K L M N O P q R S T U V W x Y z