On a learning curve

With the new V&A museum plus a regenerated waterfront, Dundee was in dire need of a new station with the right presence. James Parker describes how the architects steered an evolving project that produced an unconventional concourse building topped by a hotel.

A victim of transport planning riding roughshod over urban environmental quality in the 1960s, Dundee’s waterfront is now being reinvented. Dramatically catalysed by the arrival of architect Kengo Kuma’s avant-garde V&A museum which opened earlier this year, the area is unrecognisable. What was a series of roundabouts and sub-standard buildings is becoming a people-friendly new district that reunites the town with the river Tay. The area now has an unconventionally-shaped new combined train station concourse building and 120-room ‘Sleeperz’ hotel, welcoming swelling visitor numbers to the city who are particularly lured by the V&A. Dundee practice Nicoll Russell Studios building is essentially a series of arches curved on plan and in section, and is something of a product of the engineering complexity that often characterises rail sector projects. As well as the resulting building’s form, this is an unusual project in that it’s a rail station commissioned by the city council. Project architect for Nicoll Russell Studios, Graham Steel, explains to ADF how it forms part of a much wider scheme to improve the waterfront: “The council had for years recognised that it was a barrier between the town centre and the Tay.” He adds: “They came up with a plan which was to create a grid of streets taking you to the river.” When the Tay road bridge was constructed in 1966, it to some degree blighted the area, with a road network leading off it constructed on reclaimed land, plus now-demolished buildings including a public swimming pool, casino and hotel. What were historic docks had become an eyesore. Nicoll Russell Studios’ involvement led from their work with engineers Jacobs throughout the UK, including a bus transport interchange for Dundee City Council. It was Jacobs’ work for the council looking at how to build a road bridge over the railway line in front of the station – as part of reconfiguring the convoluted traffic system – that prompted the municipal authority to look at creating a new station concourse building, and subsequently the addition of a hotel. Steel explains: “The existing bridges were in the wrong place and weren’t strong enough. The council had always had its eye on the station as a project, so it sort of began to grow.” The scope, and thus the design brief for the project evolved considerably over the years since its inception, with the architects doing a series of studies. Steel describes the council’s rationale for what would be a public-funded project: “The V&A was going to be constructed, but they had this relic of a station which was letting the whole thing down.” The plan to add a hotel came later, once the architects were appointed – they were looking at putting some form of accommodation over the site, and in parallel, the council was looking at hotel capacity in Dundee. “They identified there was a need, and the two things fitted together,” says Steel. The added revenue from a hotel tenant was an obvious plus, but also ties in to a clear precedent from station/hotel hybrids seen across the decades. The station previously had a GRP-clad 1960s white concourse/entrance building, presenting a fairly nondescript face to the city, says Steel: “Something with greater presence was called for in what is a very visible position. In addition, “the new building needed to be bright, open, generous, accessible and legible, everything the original building was not,” says Steel. The original Victorian brick station which sits in a cutting below the new concourse building is retained, with its platform and metal zig-zag roof both curving to follow the railway line as it comes into the city after crossing the Tay. It then dips underneath the newly developed waterfront to remerge in the east end of Dundee, but rather than its overall physiology, the constraints the line presented for the site were the chief concern for the design team.

Arch rival

Following on from Jacobs’ initial work to create the road which now sits in front of the station, the emerging project to replace the concourse building was initially an engineering challenge. The new structure would have to span a main railway line – which was main practical reason behind its arch-like form. Graham Steel explains: “We were spanning two abutment walls, and coming in at different angles, reconciling different things, the geometry of the railway line coming in at an odd angle relative to the street grid that had been established by the council.” There were fixed constraints – the level of the track, the roads above it, and the vertical and horizontal clearance needed for the trains. Steel says: “We were spanning across a railway cutting effectively with two bridges, one at concourse floor level, and another ‘bridge’ carrying the hotel floors above; it basically formed an arch.” In order to take the diagonal forces into the ground, the specially designed steel beams that make up the concourse floor tie the two ends of the bridge/arch together, dealing with the sideways ‘thrust’ forces. The depth of the floor was constrained by the road above and the clearance required from the trains below. The building is highly unusual in that it is articulated on plan, following the train line – and giving each hotel room above a slightly different view – however its structure is also curved in section, with a triple height arching entrance. Says Steel: “You wind up with an interesting concourse space which is very three-dimensional, but creates the situation where the building is wanting to lean over towards the west.” With the eccentric load created by the building’s curve, steel sizes needed to be “pretty substantial” says the project architect. “Buried in the building are rigid frames, forming an extra cross-braced frame.” Above the ceiling of the column-free concourse are a diagonal network of steel columns and cross bracing. This structure, Steel admits, “is pretty chunky, and wasn’t designed to be seen,” and has been covered by four pieces of stretched white tensile fabric, which willingly accepts the building’s curving geometries. “There’s a lot of twist to the shape, says Steel, “to try and do it with a rigid material would have been almost impossible.” The building’s form, while driven by structural necessity, also references the grand railway station arches of the past, such as St Pancras and York. Steel adds: “Very often, they are hidden behind a big facade, in this case it’s not.” BIM (Revit) was essential to resolving all of the competing variables in the design, and it also helped support collaboration in the design team. Graham Steel: “The three-dimensional model was absolutely invaluable; I think we would have really struggled without it. The steel fabrication model slotted into the 3D model and we were constantly able to check the three-dimensional impact as the design developed.”

Into context

The six-storey new building (three stories of concourse/cafe plus a three-storey hotel), is the first large-scale building which visitors to the city encounter, heading in from the west. “It effectively bookends the western edge of the waterfront,” says Graham Steel. He admits it’s a somewhat unusual urban site, as the building’s overlooked on all sides, the street pattern meaning it cannot connect with any buildings. Due to its being articulated in a curve, its ends address both the Malmaison Hotel – housed in a historic building to the north, and the V&A and Scott’s ship The Discovery to the south east; both can be viewed from the station’s cafe. In what is something of a ‘classical’ plan, the concourse building and hotel terminates a new west-east route, Earl Grey Place. This cuts between two new commercial buildings facing the station and a green space beyond, which is already used for events, and runs to the waterside. Steel comments: “In a sense, there’s a certain classical element to the building,” citing its exposed steel columns to front and rear. The building frames a small, roughly crescent-shaped plaza to give pedestrians some refuge from the heavy traffic nearby. Designed by the council, it features polished concrete ‘pebbles’ which are proving popular as seating. Commenting on the newly created public realm, Steel says, “It was important the facade onto the plaza was of true urban scale, and avoided the ‘flatness’ that is a feature of many modern buildings.” He adds: “The deeply inset bedroom windows, subdivided by columns, creates a kind of giant order that feels appropriate to the status of the building.” These windows also give hotel guests added privacy on the inner curve of the building, preventing views in from other rooms. The building has glazed corners, butt-jointed windows to the south allowing these hotel rooms fantastic views across the Tay, some being triple glazed to attenuate noise from trains. The north and south elevations are glazed in part – including the cafe space covering the first three levels to the south and the hotel entrance and stairwell facing the town to the north. At night, this provides “a kind of beacon,” says Steel. There is a “conscious difference” between the more transparent lower floors and the more closed, intimate upper hotel floors, accentuated by the fact the building is deeper in plan on the bottom three levels due to these housing a different set of functions. However, to the front, the whole curve is clad in terracotta, bar the very bottom which is in granite to resist damage. The upper stories and end elevations are clad in a mix of curtain walling and anodised aluminium panels, which are acid etched in four different shades and randomly distributed. Terracotta also clads the bottom three storeys to the rear of the building, surrounding a glazed arch mirroring its counterpart to the front, and welcoming passengers ascending via escalators (or accessible lift) from the platform level below. Steel comments on the choice of material: “We were conscious of a desire to pick up on some of the better stone in Dundee, some of the buff colours and lighter colours.”

Interiors

Internally, the concourse space is typically uncluttered to allow efficient passenger movement, with the cafe accessed to the left on entering via the main sliding doors, signalled by a piano outside for public use, and a retail unit and ticket office to the right. Passengers then descend to platform level through a newly refurbished circulation, also designed by Nicoll Russell Studios. As well as designing a large diagrid rooflight over the escalators and new tiled walls, they also squeezed the minimum size of escalator kit between the two retained Victorian columns which hold the existing metal roof up, as well a through-lift alongside. “We were trapped between two existing platform edges, which could not be adjusted,” says Steel. “We had to go for the narrowest lift, escalators and stair that Network Rail would accept.” The cafe has a first floor balcony looking into the triple-height space but also an external south-facing one, allowing passengers to sit outside overlooking the Tay and the V&A. While it will lift them above the traffic somewhat, it also gives the “certain kind of buzz” inherent to such a busy urban location, says Steel.

Passive approach

With the architects aware that a large area of south west-facing glazing to a concourse could create an “unacceptable level of solar gain at certain times of the year,” a passive ventilation strategy was adopted to offset this. A thermal model confirmed this supposition, and Nicoll Russell suggested that because of the arched shape of the space, this could be mitigated by venting the concourse at high level with a stack effect passive vent that ascends through the hotel levels. Running the length of the concourse ceiling is a damper consisting of a louvre grill, which opens automatically when the air temperature hits a prescribed level. “If necessary, the main sliding doors will open automatically, providing make-up air to encourage the stack effect to take place,” comments Steel. In addition, the concourse’s single-glazed bolted fin glazing has a dot pattern screen printed onto it, to further reduce solar gain and glare. There are also standard ‘Colt’ type louvres within the terracotta cladding to front and rear, providing further natural ventilation to the concourse space. To avoid a “big box of plant sitting on the roof,” the plant serving the hotel and cafe are hidden in the space between the arch and the underside of the hotel.

Conclusion

This is an unusual scheme in many respects, yet its form partly results from tackling a set of challenges that are common to many other rail projects. These include remedying previous and unsatisfactorily ad hoc solutions, and dealing with complex geometries. The result is what the project architect calls an “organic shape,” which makes a virtue of this in addressing its city and the rescued waterfront which it helps provide a link to. It is a fitting terminus to both railway journeys to what is a revitalised Dundee, and a new and exciting urban quarter.