The Italian Job
The Buro Happold-engineered Oval Lingotto speed skating venue was certainly put through its paces at the 2006 Winter Olympic Games in Turin.
The rink, for which Buro Happold provided structural and building services engineering, has been operational since December when the venue hosted a trial event to test systems and allow athletes to familiarise themselves with the facility.
The venue contains a 400m circumference oval ice track for the Olympics, which will be used as an exhibition space after the Games. Then it will act as an extension to the adjacent Lingotto Fiera trade and exhibition centre, formerly the Fiat car factory which was used as a backdrop for the car chase in the 1960s Michael Caine film, The Italian Job.
The design team, which includes international architects HOK sport architecture and Studio Zoppini Associati of Milan as well as Buro Happold, had to meet three major criteria for the venue. These were: creation of a world-class skating venue; to provide a flexible dual-use venue that offers skating for the local community in winter and additional exhibition space in summer; and to improve the local environment as part of the massive redevelopment efforts for the district, once renowned for its car manufacturing.
Controlling ice quality proved to be the main focus of the design, particularly without the natural advantage of altitude seen in previous Winter Olympic sites and so the design team was encouraged that a race time within one second of the world record was recorded during the first event.
Several factors have to be closely controlled, not least the amount of sunlight entering the building. This has resulted in only the north façade being glazed, permitting views of the former Fiat factory next door.
Other factors include the amount of lighting required to provide the best quality media coverage and the variable heat load created by spectators, which can create an increase in temperature of up to 6ºC.
Buro Happold’s lead engineer on the project Steve Macey says: “The challenge was to introduce the right amount of technology behind the scenes to create the best quality ice to enable the athletes to achieve record breaking performances.”
One of the most challenging aspects for the design team was the arena’s soaring roof structure, which covers approximately 26,500 m². Spanning over 100m and curving from east to west, the roof has to be capable of carrying substantial snow loads, yet have a lightweight appearance.
Having settled on long span steel trusses as the most appropriate engineering solution, the team had to establish how best to space the primary and secondary trusses, taking into account the width of the roof. At 216m, this is governed by the size of the speed skating oval and the seating areas, which can accommodate up to 8,500 spectators.
To allow for use as smaller exhibition spaces, provision has been made within the roof structure to accommodate sliding cross walls and acoustic curtains, enabling conversion of the auditorium into three halls.
The solution was to divide the 216m length into six 36m-wide bays, with six primary trusses. The efficient 72m-wide structural system devised by the engineers comprises two primary trusses, a central 36m spanning truss, and two 18m spanning cantilevering trusses on each side.
To facilitate winter and summer use, the design team also had to consider the issue of thermal expansion, which is likely to be substantial, given the wide range of temperatures the structure will be subject to. Rather than ‘lock in’ stresses by restricting the movements of the roof, the engineers were able to preserve its lightweight aesthetic by providing movement joints and allowing the roof to sway (within serviceability limits) about its support points.
The position of the movement joints in the plane of the roof coincides with the potential future subdivision of the hall, and by raising the tips of the cantilevering trusses to a constant height the engineers have allowed for the future introduction of an acoustic barrier between the exhibition spaces. This solution has also helped to create a more interesting roof form.