Dalmarnock Power Station, Riverside

Case Studies

DALMARNOCK POWER STATION, RIVERSIDE, GLASGOW Description: Land Reclamation and Remediation Form of Contract: NEC3 Option A Duration: 60 weeks Contract Value: £3,400,000 Client: Clyde Gateway Clients Representative: Grontmij

This reclamation contract was on the site of the once colossal Dalmarnock Power Station, located in the East End of Glasgow. The power station was closed in 1977 and subsequently demolished to ground level with the demolished structures used to backfill the substantial underground voids (basements, tunnels etc). Our scope of work involved major land reclamation, remediation of contaminated soils, bulk earthworks and drainage to provide development platforms on the 9ha site. The site is located in a sensitive area bounded by residential properties, the River Clyde and a railway line which required close liaison with all stakeholders for the duration of the project.

Dalmarnock Road Drainage

Crib wall

Borrow Pit Dalmarnock Road Tunnel

SUDS Pond Power Station Building Footprint Railway Line

Perimeter Wall River Clyde Walkway

River Clyde

By far the largest element of the reclamation works involved the controlled demolition of the old power station foundations. Over 60,000m3 of reinforced concrete (R.C.) was broken out, at depths up to 5m. Careful consideration was given to neighbouring properties during this stage of the work. To reassure residents during this stage of the contract, we undertook numerous structural surveys of properties prior to demolition and established vibrographs at strategic locations to monitor vibration during demolition. All concrete was processed to provide engineered fill for the required development platform.

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The removal of the substantial perimeter wall included a section which ran parallel with the River Clyde Walkway. We developed our methodology to facilitate demolition operations whilst maintaining access to pedestrians. Using a combination of timber hoarding and banksmen we removed the brickwork wall and the significant R.C. foundations without closing the walkway.

The demolition of an existing reinforced concrete tunnel located under the footpath of Dalmarnock Road was a particularly complex aspect of the reclamation scope. Working collaboratively with our client’s site team, we developed a solution which involved retaining the Dalmarnock Road side wall and tunnel base slab (highlighted blue) to prevent the road from being undermined. The roof slab was carefully saw-cut and Roadside wall removed along with the side wall to the site side Soffit & Side and base slab Wall removed retained and (highlighted red). Our methodology allowed us to maintain Photo from within backfilled two-way traffic flows through the reduced excavation tunnel against requirement.

In addition to the removal of R.C. foundations, we also had to selectively excavate and treat contaminated soils (hydrocarbons, heavy metals) from locations on site. In total 12,000m3 of soils were excavated and treated during bulk earthwork operations. Forming the base layer of development platform earthworks, contaminated soils were treated with a mixture of lime and cement and placed, at depth, in a solidified fill layer. This solidified layer was then capped using the 60,000m3 of recycled concrete fill and finished with 17,000m3 of site won sub-soils and 8,500m3 of imported topsoil. We worked closely with the Client’s Designer to develop the earthworks solution to overcome a shortfall in sub-soils by establishing a borrow pit within the site to provide the balance of material required.

A remarkable discovery, in the form of unexploded ordinance, was made during bulk earthworks operations. Our site management staff were commended by the emergency services and Client for the manner in which this unexpected incident was dealt with.

The drainage element of the project included both onsite and offsite works. A new section of 1050mm diameter sewer was constructed on Dalmarnock Road under traffic management. Onsite drainage included the construction of a substantial SUDS pond with two outfalls to the River Clyde. A Crib Wall was constructed to overcome a level difference and limited space between the pond and the existing road bridge.

Reclamation works were finished off with a variety of landscaping, a perimeter fence and surfaced paths and access tracks.

Continuing our commitment to community benefit initiatives, we recruited and trained two new employees who had previously been in long term unemployment.