Topped by a curving, signature steel roof, Ireland’s new national stadium is set to enhance Dublin’s skyline and offer spectators and players superb 21st century facilities. Martin Cooper reports.
Dublin’s historic Lansdowne Road stadium is in the midst of a multi-million pound redevelopment programme which will ultimately result in a brand new £360M, 50,000-seat arena fit for the demands of modern international sport.
Rechristened the Aviva Stadium, the ground, to be primarily used for international rugby union and football, is scheduled for completion in April 2010 with a football match against former world champions Argentina already pencilled in for August next year.
“We are pretty much surrounded by residential development, but we have a stadium which perfectly fits the site.”
Michael Greene, Lansdowne Road Stadium Development Corporation
There is no doubt the new stadium has become a feature in the skyline of south Dublin, being set in a low rise area of the city. However, it will not overwhelm nor impact negatively on the surrounding residential streets. In fact, the adjacent houses and the existing Lansdowne Road site dictated the design from the offing.
There are railway tracks and underpasses to the west, a culvert to the north and rugby pitches that had to be maintained to the east. Extra space for the development was created by a realignment of the pitch once the old stands had been demolished and by constructing an access podium over the neighbouring railway lines. The retained training pitches were also realigned and converted into one pitch.
Moreover, it is the site’s suburban context that generated the need for the stadium’s signature undulating form.
“We are pretty much surrounded by residential development, but we have a stadium which perfectly fits the site,” explains Lansdowne Road Stadium Development Corporation project director Michael Greene.
- Clients Irish Rugby Football Union (IRFU), Football Association Ireland (FAI)
- Project Manager Project Management Group
- Architects Populous, Scott Tallon Walker
- Main contractor John Sisk & Son
- Structural engineer Buro Happold
- Steelwork contractor SIAC Butlers Steel/Cimolai Consortium
“The full height of the stadium is to the east and west. It is lower to the south because of houses, while the north stand has a single tier so that other nearby residential properties are not overshadowed.”
The Aviva Stadium is 15m high at the north side’s single tier stand, rising to four tiers and 40m on the east and west sides with a slightly lower south side.
Organic sweeping structure
The challenge was set to design a roof that could accommodate these changing levels and the result is an organic sweeping roof structure that curves from its apex down to the north of the site joining the walls of the stadium giving the impression the whole structure is lower than it is.
To achieve this distinctive shape, engineer for the project Buro Happold came up with a two-part roof design which consists of a horseshoe steel truss around three sides of the ground, connecting to a more conventional and dependent structure at the lower, north end. “It’s a very complex steel design and the roof would not have been possible without modern 3D computer design,” says Greene.
“This unique design creates weather protection within the site’s constraints.”
Michael Greene, Lansdowne Road Stadium Development Corporation
“But this unique design creates weather protection within the site’s constraints and ensures everyone will have excellent views of the pitch.” The roof is approximately 200m in diameter with a covered surface area of about 23,000m².
The primary horseshoe truss runs around the east, west and south of the site. Most of the weight of the roof is carried by this truss, which is supported on two large 15m high by 2m diameter concrete columns, positioned either side of the north roof. Extra support is provided by an edge truss which connects to the back of the stadium’s concrete upper tier.
- Seating Capacity Lower tier 20,000
- Seating Capacity Premium tier 10,000
- Seating Capacity Box 1,500
- Seating Capacity Upper tier 18,500
- Restaurants 3
- Kitchens 9
- Kiosks/bars 69
- Stadium height 47.65m
- Stadium Length 189m
- Stadium Width 203m
- Steel tonnage 5,000t
This edge truss connects to the primary truss via a series of spur trusses. The actual roof structure is supported on a series of tertiary trusses which launch off the edge truss, spanning across to the primary truss and cantilevering out into the stadium bowl. The 95m long North Stand roof is much simpler and is formed by a series of curved truss beams and columns.
The complex steel roof structure is critical to the stadium’s elegant, sweeping form. But this elegance was aided by the fact that there was no demand for the roof to be fully enclosed − this allowed designers to minimise coverage, with the knock-on effect of reducing loadings and keeping the truss dimensions minimal.
There was, however, a desire for a roof covering that would maximise the exposure of the pitch to natural daylight and this led to the decision to clad the roof with polycarbonate louvres. “The curved roof shape led to extremely complex geometry for the steel to cladding interface,” explains Project Management Group project manager Pat Molloy.
The steelwork package is being carried out by a consortium comprising Italian contractor Cimolai − which is fabricating and erecting the roof − and locally based SIAC Butlers Steel that erected the stadium bowl steelwork. This primarily consisted of the upper tier rakers.
The main roof steelwork was initially intended to be tubular, fully welded structure. However, Cimolai wanted to minimise working at height and so opted for a bolted structure with all bolted connections concealed with sleeve plates.
“This offsite solution has been a boon for the project as a whole,” explains Molloy. “All the roof steelwork is being assembled on the pitch area and lifted into place by large crawler cranes, with no welding to be done there is one less trade on an already busy site.”
Before the steelwork package kicked off last year, much of the concrete works, which include most of the stadium’s terrace units, columns, rakers, beams, stairs and tunnel walls, had already been finished. More than 35,000m² of cast insitu concrete has been used on the project.