All change: the Stock Exchange

A £90m regeneration project near Stockport railway station aims to breathe new life into the city center

Artist LS Lowry featured the neighboring viaduct in his work. CREDIT: Crispin Eurich Photo Archive

A a series of photographs from 1962 show the artist LS Lowry looking typically cheeky as he looks out over Stockport Viaduct, once the world’s largest viaduct. “I only deal with poverty,” he once declared. “Always with sadness. You’ll never see a cheerful picture of me.” The artist spent his life creating compositions of industrial landscapes in his beloved Lancashire. He spent a lot of time in Stockport, and the city’s railway viaduct, which opened in 1842, with its 28 arches and 11 million bricks, appears in a number of his works.

Although the viaduct remains, the neighboring site in the city centre, where Lowry was in these photographs, is now home to Willmott Dixon’s £90m Stockport interchange. The town center location has been cleared a couple of times since the 1960s; more recently, an old bus station – a sprawling quasi-parking lot with multiple lanes and single-storey shelters – has been put out of its misery.

It is now to be replaced by a modern terminal with 18 bus stops, a covered passenger hall and shops. The bus station, which will accommodate up to 168 departures per hour, will be crowned by a two-hectare park which will link to the much smaller viaduct structure, the Wellington Bridge. The project also includes a 15-storey block of 196 rental flats, as well as a new cycle lane and a 90-tonne bridge to link the interchange with the town’s railway station, located about 150 meters to the south. The project is expected to be completed in the spring of 2024.

While it would be unfair to characterize 21st century Stockport as dreary, local politicians are talking about the programme’s potential for regeneration. Leader of Stockport Council, Labor councilor Elise Wilson, says it will “completely transform the look, feel and presence of Stockport”, adding that “for the first time, we will have a fantastic city center park for sit and enjoy the incredible views of our impressive viaduct”.

Willmott Dixon has been involved since 2019. The family-owned contractor has a contract totaling approximately £90m, which has been selected through the £50m+ Pagabo Major Works framework. The scheme’s client is Transport for Greater Manchester, a subsidiary of the Greater Manchester Combined Authority. However, it raised funds from other stakeholders including Homes England, Stockport Metropolitan Borough Council (which will own and manage the park) and CityRise, a joint venture between developer City Heart and Rise Homes (which will own and manage will rent the house).

“You can’t imagine the potential implications of making an urbanization of these characteristics in the middle of the village and [trying to] keep everyone on board”

Mike Lane, Willmott Dixon

Work began on the site in the summer of 2021 following late design changes. “[The client] they made some initial designs, but only had a scale core [in the block of flats], and we told them they needed two,” explains Andy Howarth, Willmott Dixon’s operations director in charge of the project. “The fireman came and agreed with us.”

When the order finally came, Willmott Dixon began removing the existing bus shelters and foundations with subcontractor Howard Stott Demolition. After the base was repaired, the team inserted 600 mm continuous flight auger piles, which were quickly drilled 10 meters into the sandstone bedrock. The project has about 585 piles, 235 under the block of flats and 350 under the interchange.

What followed was a lot of concrete: in total, the project uses 19,000 cubic meters of it in the foundations of the scheme, the interchange structure and the residential tower.

boundary wall

The team started the structural work by building an 8 meter boundary wall to divide the residential scheme of the interchange and the park, as some of the strong concrete columns of the interchange were to be built later or they would obstruct the frame needed to create the wall. Concrete framing subcontractor Mayo Civil Engineering is Willmott Dixon’s largest supplier for the project, carrying out around £20m worth of work under an umbrella contract covering the interchange and residential building. (Willmott Dixon often splits parts of the project into its contracts or procurements; here it uses Mayo MEP and A&B Engineering to do the MEP for the residential and interchange aspects, respectively, and RED Systems and Hadrian Group, respectively, to provide curtain walls for to each.)

The residential building frame is a standard residential frame, says Howarth. The two cores were slip-poured, and the floor slabs of 14 dwellings were subsequently created with in-situ concrete frames, reaching a rate of one floor every six days. Although the pour was only completed at the end of May, the equipment is well under way, thanks to the use of a five-story steel structure protective screen. The screen, which was raised hydraulically or by crane, keeps out bad weather while windows are added to the finished floors, making them ready for installation, while the floors are poured. The residential building is being clad with brick slips over rockwool insulation, while the windows have aluminum frames.

The exchange structure is more complex. It is supported by circular concrete beams 7 meters high, 73 in total, over which the builders poured 109 beams up to 2.2 meters deep and 15 meters long before placing a slab. The west edge of the slab is cantilevered where it meets Wellington Road, where people will be able to access the new park as no load is allowed on the Grade II listed Wellington Bridge structure. “It was specialist and unusual stuff,” says Howarth. He adds that “making sure thermal movement is accounted for” through motion joints on such a large structure was one of the most difficult technical challenges. This was especially true given the need to ensure that they did not affect the placement or hanging of the cladding, which could not be cut in situ.

Now that the pour has taken place, Willmott Dixon has started work on the park, which will sit above 1.2 to 3 meters of accumulation on the slab. The piling is lightweight, reducing the amount of concrete required in the structure: most of it will be made of polystyrene forming voids, while the plants will sit on a specialized ultra-lightweight GeoCell rock substrate.

The build-up also includes an innovative drainage system to help deal with flash floods. The slab is topped with a waterproof polyurethane layer, on top of which are 85mm blue roof attenuation cells. When it rains, water will pass through the park’s porous surface and settle in water cells until it is discharged into the Mersey once the river has calmed down.

At the edge of the park, a large oval hole in the slab, dubbed the Oculus, reveals the ground-level circulation area for buses. The terminal features a glass curtain wall on the interior facade of the Oculus and its exterior walls. The original designs had the rectangular slabs hung horizontally, but Willmott Dixon realized that this would be difficult on a curved building, so after some design development, he opted to install the cladding vertically.

Local commitment

Despite the technical challenges presented by the complex scheme, which has had up to 300 workers at the same time, the contractor’s most difficult task has been keeping everyone happy. This is partly due to the abundance of customers and stakeholders, let alone diverse ones planning, roads and arboriculture teams at Stockport council.

“Their requirements are not necessarily what
you might think,” says Mike Lane, Willmott Dixon’s operations director for the north of England. “They have a very different take on anything from design, [to] the type of product [we use and] the kind of people who could use something, and we often have to consider that.”

A bigger challenge is keeping the locals happy while they occupy a large and highly visible part of their urban core for several years. “You can’t imagine the potential implications of making an urbanization of these characteristics in the middle of the village and [trying to] keep everyone on board,” says Lane.

However, Willmott Dixon has worked hard to win over residents and businesses. It has created 57 local jobs, provided 97 weeks of apprenticeship training and 11 weeks of work experience, as well as teaching local school children about construction and, when Construction news visited, a group of children with special needs were leaving the site’s office after enjoying a virtual reality session. It has also directed 56 per cent of its project spend towards businesses within 20 miles of Stockport.

All in all, the contractor believes it is helping to breathe new life into the old arches of Stockport Viaduct. “It’s not to say that there aren’t people who have raised challenges and laid them on our doorstep,” says Lane, “but mood music is really very positive and people see that level of investment in his door, and he landed pretty well.”