Olympic feat sees roof installed

Client : Palram

Translations (Word .doc files) : <fr> <d> <i> <es>

WHEN a major change had to be made to the design of the impressive roof that would cover the main stadium of the Athens 2004 Olympic Games, contractors faced unique problems.

The acclaimed Spanish architect Santiago Calatrava was chosen to design the Athens Olympic Stadium Complex.

The complex would also host the Olympic Indoor Hall, the Olympic Aquatic Centre, the Olympic Tennis Centre and the Olympic Velodrome.

The ‘jewel in the crown’ of this complex is the main stadium itself, which is set to be the signature piece of the Athens 2004 Olympic Games.

It was proposed that the main stadium itself, previously home to the AEK Athens and Olympiakos football teams, would become the Spyros Louis Stadium, named after the winner of the marathon of the first Olympics in the modern era, held in Greece, in 1896.

The Greek Ministry of Culture was put in charge of the project, and the deadline for completion was July 2004.

The scale of the project was huge - for the main stadium alone the roof would cover 24,000 sq metres, the size of three football pitches, and the two main steel arches would weigh over 12,000 tonnes.

The two giant arches standing up to 80 metres at their highest point - a fitting architectural masterpiece to top the Athens Olympic Sports Complex (OAKA) at Maroussi, the centrepiece of the Olympic Games 2004.

The world’s spotlight would be focused on the Greek capital for the sporting event of the year.

The original Calatrava design for the main stadium incorporated glass panels suspended from the arches to shield spectators from the searing Athenian sunshine.

The original roof of the stadium offered 30 per cent protection to spectators whilst the new Calatrava design would increase coverage to 90 per cent.

The design itself was both innovative and challenging - but added to the engineering and logistics challenges was the plan to build the roof away from its final position and then slide it into place. In November 2003, Greek authorities raised safety concerns about the use of glass.

After much research and discussion, it was decided that polycarbonate sheet would be used instead and the contract, with exacting aesthetic and performance criteria on colour-match, heat reflection, light transmission and abrasion resistance, was put out to tender.

The architect and Greek authorities also wanted to preserve the integrity of the original design.

Thermoplastic sheet specialist Palram produced, almost overnight from its UK based Palram Polycarb factory, its specially created PALSUN UV2 Solar Olympic product.

PALSUN UV2 SOLAR OLYMPIC was colour-matched exactly to the original glass design and met the performance criteria of light transmission, abrasion resistance and most importantly UV protection and heat reflection. "Matching the appearance of the glass was only one consideration" said Mike Heaven, Palram’s UK Sales Manager, "the key part of Santiago Calatrava’s design was to protect spectators from the Greek summer sun". PALSUN UV2 SOLAR OLYMPIC offers protection from harmful UV wavelengths of solar radiation and reflects up to 60 per cent heat which would otherwise be transmitted along with light through the roof panels.

To design a high performance polycarbonate sheet with light transmission and heat reflection Palram incorporated its SOLAR CONTROL technology.

SOLAR CONTROL technology enables Palram to suspend metallic particles in the polycarbonate resin which when evenly dispersed in the extruded sheet act like miniature mirrors reflecting a given amount of solar radiation which would otherwise be converted and pass through the sheet as heat energy.

Palram developed Solar Control technology for industrial and domestic roofing and glazing applications around the world.

The Calatrava specification would set new standards for the Palram Polycarb factory by combining SOLAR CONTROL technology with colour-matching, UV protection, abrasion resistance, sheet dimensions and high quality - combining to create a unique high performance product.

Palram’s ability to produce samples quickly, and the fact that the product matched the architect’s exacting requirements, helped the company to clinch the deal ahead of international rivals.

Amos Netzer, chairman of the Palram Group, said: "This contract was almost tailor-made for Palram.

"Versatility to produce short-run sample sheets, fast production lead time, high quality and logistical solutions are the foundation stones of our business."

The 4,750 panels are 12 mm thick and measure 4,920 mm x 1,000 mm and weigh about 75kgs each.

In total, the sheets weigh more than 320 tonnes and Palram Polycarb produced the sheets at its Doncaster factory in the UK over a period of 10 weeks - a problem-free process that was completed within the agreed timescale.

Palram Polycarb integrated the specifications into its operating procedures controlled by the factory’s ISO 9001: 2000 quality accreditation and created a bespoke IT logistics program within the company¹s SAP to track each panel and deliver them to site as required.

The next issue for the main site contractors, Aktor, structural steel manufacturers Cimolai, and roofing specialists Gallop, was how to erect the roof arches and install the 4,750 panels that would cover the complex.

The two giant arches each have a total span of 304 metres and provide the support for the cables that hold the polycarbonate panels in place. The two arches, 80 metres at the highest point and weighing in at over 12000 tonnes, were each constructed 70 metres away from their final positions by Italian firm Cimolai.

Once erected the arches were slid into their final position - an engineering first for a roof of this size.

The arches were moved, at a rate of 50mm an hour, and when in position the 4,750 PALSUN UV2 SOLAR OLYMPIC panels were installed.

It took a fitting crew of 110 Gallop workers on the roof coordinated by an additional 55 Gallop workers on the ground four weeks to fit all the panels.

Dinos Keanthos, the managing director of Gallop, said: "The handling and installation of the roof panels was made much easier by using polycarbonate, instead of glass, due to the sheets resilience and its comparative lightweight."

"But we had to find the answer to two engineering problems caused by the natural movement of the steel arches and the expansion / contraction of the polycarbonate" continued Dinos, "we overcome this by pre-drilling each polycarbonate panel and fitting it inside a specially designed aluminium frame."

The frame is an innovative design made specially for this project by Gallop’s engineering team and answers the technical problems whilst also assisting in the handling of each of the 4750 individual panels.

Gallop installed all the panels 2 weeks ahead of the original schedule set by the Greek authorities allowing other projects on the site space and time to be completed.

Yossi Egosi, managing director of Palram Polycarb, said: "This contract has been a great test of our versatility, quality and logistical ability.

"The specification and scheduling is very exacting and even the simple things, such as handling the sheets, has been a challenge."

Amos Netzer commented: "This roof will be the signature piece of the Athens Olympics, realises the innovative design of Santiago Calatrava and recognises the achievement and teamwork of Aktor, Cimolai, Gallop and Palram."

BACK TO CASE STUDIES MAIN PAGE