Ceredigion is visited all too infrequently, which is a shame because the area has stunning, unspoiled scenery. The problem is a perennial one in Wales – links east to west are generally good, but links north to south have always been poor. Ceredigion County Council principal engineer Alun Davies explains: "We are a remote county in west Wales. Types of industry available are limited by communications. This road [the A486] is the vital link to the M4 corridor and is the latest phase of a scheme to make Ceredigion better connected. And it is a major project."
At the picturesque town of Llandysul, the problems on the A486 are magnified. The town has narrow streets where traffic can easily be brought to a standstill. This can affect journey times from the important regional centre of Aberystwyth, which has better links to the Midlands than it does to South Wales.
The solution is to simply cut out the town, creating a 3.5km, £16M bypass around it. Once complete, the route will reward drivers with some stunning views. But this classic scenery provides the main problems for the scheme – to create a straight road through two river valleys.
The solution is to construct three viaducts – two 120m and one 160m in length, and drive an alignment through a hillside. "A better road will have a huge impact on journey times. Llandysul is the bottleneck. If something happens in the town, it can have a severe impact on the roads either side of it," says Davies. "The scheme is essential to promote the economic prosperity of Ceredigion."
Consultant Capita Symonds won the original design tender back in September 2000, but the project has had an unusually long gestation period thanks to a drawn-out planning inquiry. By the time contractor Bam Nuttall began the main works on 19 March 2008, the team had had plenty of time to refine the project.
The original design would have generated 100,000m3 of excess spoil from a total of 265,000m3 of earthworks to create 1.5km of cutting at the northern end of the scheme. "By changing the vertical alignment we came down to a balanced scheme," says Bam Nuttall project manager Roger Williams. "Initially it was left to us to re-use material, but this change was more economical, and reduced more than 2,000 truck journeys." "The real problem was getting the material out, which would have been a problem on the already congested road," he points out.
Secondly, the team altered the design of two of the three major structures, from multi-girder composite to ladder beam designs. The time did not stretch far enough to re-design the third structure, but the new structures saved some £200,000 by significantly reducing the quantity of steel required at a time when prices were at record levels.
The three main structures sit on large abutments up to 16.4m by 5.8m by 1m and piers up to 10.3m in height or spread foundations to carry the new road around the town and north over the rivers.
The project was due to open in May 2010, but this date has been brought forward to early August 2009.