Greenhills Road/A726 Strathaven Road Corridor Improvement, East Kilbride

Project Overview

Client

South Lanarkshire Council/Glasgow City Deal

Value

£19m

Duration

36 months

Designer

South Lanarkshire Council

Summary

Wills Bros upgraded 3.5km of existing road network to dual carriageway, improving journey times for traffic traveling to and from the south side of East Kilbride and improving access to underdeveloped land set aside for commercial use which will boost the local economy.

Whilst upgrading the road network, pedestrian and cycle routes were also upgraded to ensure safe passage of its users in this urban environment. This included the construction of a new pedestrian access ramp to improve access to the local country park and sports facilities from residential areas west of the facilities which up until opening of the new ramp, was done by navigating two flights of precarious stairs with push buggies and bicycles.

This required the construction of 2 lanes of new carriageway and the reprofiling and surfacing of the existing carriageway. Two new retaining structures were constructed, one being an in situ reinforced concrete wall and the other comprising CFA piles and pre-cast and in situ-concrete to form a new pedestrian access ramp.

Key Numbers

3km of new, full construction carriageway 7.3m width and another 3.5km of planning and regulating of the existing 7.3m width carriageway to adjust profile to new design levels
Excavation of 100,000m³ of material which was reused on site
A pedestrian ramp comprising 100m length of 750mm diameter
construction of new carriageway adjacent to the existing including intersections at 7 roundabouts in an urban environment
Temporary Traffic Management with intricate detailed planning was installed to maintain 2-way traffic at all times with a limited number of exceptions for the installation of utility road crossing which were carried out under 2-way traffic lights during off peak hours
Over 8km of drainage, diameter between 150mm and 750mm up to 4m depth
Attenuation crates were installed to provide additional storm storage including the use at 5 bioretention ponds with outfalls to the existing watercourse
Diversion of existing gas, water, electric (33kV and HV) and telecommunications
New, environmentally friendly street lighting
significant amount of site clearance including removal of existing wooded areas for the new road alignment which required to be reinstated with the same number of trees in the new landscape design
New trees are a mix of whips and semi mature trees including 3m high trees along the length of the project to form a tree avenue

Unique Features to the Contract and Value Engineering

The client’s design of the pedestrian access ramp called for 3 lines of CFA piles at different platform levels as the ramp structure was also required to retain embankment and the car park for the commercial property at the top of the existing embankment which needed to be cut back to make space for the new ramp.

We identified early in the contract that there was a more efficient solution for the ramp construction and by using our experienced in-house design management team, we developed a precast concrete solution to replace the front 2 rows of piles. This removed the requirement to construct a temporary piling platform 4 metres high on top of the existing carriageway and ultimately saved 6 weeks on the construction programme as well as reducing 600 lorry movements on the local road network.

Reuse of excavated material

100,000 cubic metres of excavated material was reused on site by means of lime improvement and cement stabilisation methods to allow unsuitable as dug material to be incorporated into permanent embankments and capping layers below the new carriageway.

Adapting to Covid restrictions

When this project was a little over 50% complete, restrictions were introduced due to the Covid 19 pandemic. As well as adapting welfare facilities, everyday work methods were also analysed, and solutions identified to mitigate restrictions on physical distancing. There was 7km of kerbing left to complete on the project and with traditional kerbing requiring close proximity working of operatives, this was identified as a high-risk activity with regards to physical distancing. A solution we identified and proposed to the Client which accepted, was to change the specified traditional kerb log and pre-cast concrete kerb to extruded bitumen kerbs.

This allowed for the carriageway surfacing to be completed then the extruded kerb installed on top of the surface course. As well as There were health and safety gains such as limiting close working and manual handling as well as a reduction in site personnel which eased pressure on welfare facilities during the unprecedented times.