The A77 is a stretch of road in South Ayrshire in western Scotland.

During this project, Transport Scotland built 5.5 km of offline bypass including:

• WS2+1 sections of climbing lanes.

• 2 km of paved side roads and 1.5 kilometres of access tracks.

• Three primary bridge structures comprising two overbridges and one underbridge. Two overbridges carries Gardenrose Path and Kirklandhill Path respectively over the new A77. One underbridge carries the new A77 over Alloway Road.

• Three culverts to carry the Brockloch Burn through Low Grange Road, the A77 and a pond access

• One underpass under the A77 to accommodate farm accesses.

• Two rock cuts which provided material used in the Ground Improvement Layer and capping.

• Three roundabouts; accommodation works; drainage works including the provision of pipe culverts, attenuation and treatment measures; fencing and safety barrier; earthworks; road markings; signing and lining; and street lighting.

• 5 CCTV cameras and two variable messaging signs.

Land use

During the construction of the works, the client needed the use of various stockyards across the site. The site was surrounded by greenfield land, making it challenging to store stockpiles and various other materials.

The client positioned the stockpile locations on the road that was due to be built, rather than taking up more greenfield space. This made effective use of land resources as well as minimising the long-term impacts of construction.

Innovative methods

The project used an on-site crusher to crush the rock which had been excavated. This allowed the client to re-use this on site rather than transporting it away.

It also used an innovative cable protection structure which eliminated the need for huge quantities of reinforced concrete. Instead, it used recycled plastic and air.

Geogrid monitoring for pavements

The ground was in very poor condition in various areas: the northern roundabout, under the footprint of the new road and in Culvert C2. The client carried out Cone Penetration Testing to inform a geogrid solution, which was monitoring the ground ahead of pavements being constructed.

Achievements in numbers

Locally supplied material: 169,916 tonnes (50% of total material used)
Re-used material: 83,995 m3 (49% of total material used)

Reduced waste and increased efficiency

BREEAM Infrastructure brought sustainability to the front of Transport Scotland’s decision making process. This increased the focus on reducing waste and increasing the materials that could be re-used on site.

There was also a greater focus on opportunities to minimise waste and maximise resource efficiency than there would likely have otherwise been.

Lower costs

BREEAM Infrastructure also delivered financial benefits to the project. A rented solar unit supplied power to the electric vehicle chargers in the site car park. This cut the amount of diesel needed by half and reduced the cost of the standard energy supply for the compound.

The client believes further incremental savings were made along the way thanks to the sustainability-focused decisions they took.