21 April 2009

The All England Club, Wimbledon, confirmed today that its new Centre Court retractable roof is on schedule to be ready in time for the Centre Court Celebration matches on Sunday 17 May, when Andre Agassi, Stefanie Graf, Tim Henman and Kim Clijsters will be the first players to play under the new structure.

Final testing of the roof and air-management system is being carried out. 

The air-management system has a vital role in controlling and stabilising the internal environment within the bowl – essentially controlling humidity and preventing either condensation on the inside of the roof or sweating of the grass – either of which would make the court slippery and unsuitable for play. 

Ian Ritchie, Chief Executive of the All England Club, said:  “We set out to make Wimbledon the world’s premier tennis event; the tournament the players most want to win, the tournament spectators most want to come to and the tournament everyone wants to watch. 

“The new Centre Court roof project has been a sophisticated engineering feat.  Much of the testing is complete and we are now making final adjustments ahead of the Centre Court Celebration event on 17 May.  That event is an important part of the testing procedure and will enable us to see how both the roof and air-management system actually perform under live conditions with a capacity crowd.”

Retractable Roof on Centre Court - how it works

Type of folding fabric concertina, which allows the roof to be folded into a very compressed area when not in use.
• Fabric (Tenara) is a special waterproof structural material that is very strong, highly flexible and at 40% translucent is not transparent for players/spectators but will let in natural light.  Around 5,200 square metres of fabric used. 
• Key element of the design allows natural light to reach the grass – brought about by re-contouring the fixed roof
• An airflow system removes condensation from within the bowl to provide good court surface conditions conducive to the playing of tennis when the roof is closed.
• Roof is divided into two sections, with a total of nine bays of tensioned fabric - four bays in one section and five in the other.  Each of the nine bays of tensioned fabric is clamped on either side to prismatic steel trusses.  There are 10 trusses spanning approximately 77 metres across the court.  Ends of each truss are supported by a set of bogies that move along parallel tracks positioned at either side within the new ‘fixed’ roof. 
• In preparation for closing the roof, one section is parked in its folded state at the north end of the court while the other is parked at the south end.
• The coordinated electro mechanical movement moves the trusses apart and, at the same time, unfolds and stretches out the fabric between the trusses over the court until the two sections meet in an overlapping seam above the middle of the court.
• The arch shape to the tops of the trusses helps the structure to withstand their own dead weight and loading from elements such as snow and wind when the roof is stretched and closed over the court. 
• The roof has been designed to close in a maximum of 10 minutes.  If the roof is being closed for rain, court covers will protect the grass in the usual way while closure is in progress. 
• After the roof has been closed, play can resume after a period of around 30 minutes, depending on climatic conditions.

Countdown to a new Centre Court - The Roof Timetable

Championships	Activity
2001	Centre Court Clubhouse renovated, new balconies added Centre Court South Stand terracing replaced Royal Box, TV/radio commentary boxes refurbished
2002	Centre Court terracing rows A-H replaced
2003	Gate 3: Demolition of old Wimbledon Museum Shop, Barclays Bank and turnstiles to make way for new Museum Building including Club offices
January 2004	Announcement of new Centre Court retractable roof, increase in capacity to 15,000, new wider padded seats (470mm seat spacing) and new restaurants/bars for public and debenture holders
2004	Gate 3: Museum, Turnstile and Club Offices building concrete structure complete to ground floor level New ticket booths operational from Church Road
2005	Gate 3: Museum, Turnstile and Museum Building (Club Offices) concrete structure continues Diversion of essential services under and around Centre Court Centre Court terracing (rows J-T) replaced Design work on the new roof, North and East Stands well advanced
2006	Enabling and infrastructure works start to strengthen the court foundations and prepare for air-management system AELTC staff relocate to Gate 3 Museum Building (December 2005) New Museum opens (April 2006)
2007-2009	Roof model testing carried out in Rotherham
2007	Demolition of East Stand and old Club offices Removal of existing roof Piling and construction of new East Stand frame and floors East Stand rebuilt and terraces operational No roof on Centre Court Extra six rows of terracing completed Centre Court restaurants/bars in situ but not open – used as rain shelters
2008	Installation of new fixed roof East Stand building finished and fully operational Refurbished North Stand including Centre Court Debenture Rooms operational Completion of new public and debenture facilities within East and North Stands, including enhanced and extended dining/lounge areas for Centre Court Debenture Holders and 400-seat Wingfield Restaurant for public, 10 new hospitality suites Capacity rises to 15,000 with addition of 1200 new seats Installation of the first two moving roof trusses No.2 Court shell complete
2009	Completion of moving roof trusses  Erection and completion of moving roof Fit fabric covering to sliding roof Commissioning and testing of roof and environment of Centre Court.  Construction of new permanent Gatehouses at Gates 4 and 5 Retractable roof and air-management system operational.  All new wider, padded and more comfortable seats installed on Centre Court No.2 Court complete and operational

 Additional Information

The new Centre Court roof comprises two distinct roof forms: the main fixed roof to the perimeter of the Court which is surmounted by a translucent retractable steel and fabric “concertina like” structure.

The design for the fixed perimeter is modelled on the 1922 dodecahedron form which provides the distinct intimate Centre Court atmosphere with a droop down leading edge to focus spectators’ eyes to the action on the grass court.  The use of the translucent fabric for the retractable element affords natural light into the arena and in part retains the open-to-air quality of the 1920’s stadium.

The relatively lightweight steel truss and fabric retractable roof is set above the fixed perimeter roof so as not to impinge on the spectators’ view and perception of the grass court in either the open or closed mode.  It also retains the 1922 dodecahedron roof form when viewed from the terraces below.

The roof is designed to provide appropriate playing conditions when the roof is deployed in adverse summer weather conditions; specifically:-

• Light – the translucent Tenara fabric will permit adequate levels of light for play in most daylight conditions; where natural light fails to meet the levels required, it is supplemented by a bespoke design sports lighting system (permanently installed on the trusses), which has been designed to provide compliant light conditions both for play and for media coverage.  There are 72 indirect, truss mounted sports luminaires and 48 direct truss mounted sports luminaires.  On the turf, horizontal lighting level is 3,200 lux and on the vertical (for service and shots in the air) is 1,900 lux.
  
  
• Wind – the roof can be safely deployed in wind conditions of up to 43 mph (69 kph).
  
  
• Rainfall – the roof is designed to be weathertight.  Rainfall on the fabric roof is rapidly dispersed to the two sides as the top profile of the roof is a curve; at the sides the water falls into gutters and then into the main surface water drainage system.
  
  
• Internal environment – the air systems are designed to firstly control and then stabilise the internal bowl environment at the specified levels (24 degrees C +/- 2 degrees C, with 50% +/- 10% relative humidity based on ambient conditions of 27 degrees C with 72% RH; if ambient temperatures rise, the bowl temperature will be maintained provided ambient RH levels fall), to prevent condensation on the inside of the roof or sweating of the grass, and to provide a fresh air allowance into bowl of eight litres/second/person.
  
  
• Seats – the new seats are padded and more comfortable.  The seats are wider and the spacing between them (centre to centre) has also been increased.