Wimbledon Roof

Description

The retractable roof comprises a series of ten cross spans, each of these is referred to as a truss. The 10 trusses are split into two operational sets of five. Each truss weighs 100 tonnes and is required to support the 5,200 square metre roofing membrane. Each of the trusses is connected to the next by means of mechanical actuators and as each section extends, a waterproof, folding, translucent fabric called Tenara is pulled across to form a weatherproof shield for the court below. All of this takes place at a height of 16metres above the court below.

A total of 214 moving elements are required for the roof to operate and they are each reliant on a complex control system comprising some 40 control enclosures and 21 PLCs to provide synchronised operation. A complete deployment (closure) of the roof takes only eight minutes at a speed of 214mm/s all the while a redundant site-wide PLC/SCADA and communication system ensures that the defined fault tolerance between all command and control stations is not exceeded. High speed data acquisition of operational data is utilised to provide historical data storage which assists with ongoing monitoring of the system and helps to guide future maintenance requirements. An innovative automatic ‘pre-test’ routine is performed daily to defend against a component failure during roof operation. This entails the control system independently oscillating and verifying all of the moving elements to ensure the system functions faultlessly when required.

A control desk provides the interface between the roof’s control system and the operations team. Whilst the system itself is complex, we have designed and implemented a simple user interface which allows non-technical grounds staff to safely operate the roof. All movements can be performed by following predefined sequences, using buttons on the desk with a SCADA system providing an additional back-up.

Maintenance and availability of the roof is of paramount importance and to assist with the associated requirements, a high speed data acquisition database system has been incorporated. This provides an interface between the data which is being supplied by each of the truss PLCs and presents the information to a maintenance engineer. In order to maximise speed and accuracy, operational data is stored by an on-board memory within the PLCs, until the truss movement has been completed. This truss movement data is then transferred to the control computer.

Once the roof is closed, it takes between 10 and 30 minutes for the court’s environment to stabilise. The Tenara fabric still allows natural light to pass through onto the grass and the airflow system removes any condensation. Although the roof is translucent, LED sports lighting is installed within the roof which becomes operational once the roof is closed. The roof can be safely operated in wind speeds of up to 43mph (69kph).

Outcome

Prior to the 2009 championships, Wimbledon Centre Court roof was tested at a special centre court celebration in May of that year which saw past champions playing in front of a capacity 15,000 strong crowd. The roof really came into its own at the 2009 championships and has been used at every tournament since. As well as providing cover from the rain, the roof can be partially deployed in order to protect the crowds and the Royal Box from the glare of the sun.

Fairfields Engineers continue to provide regular preventative maintenance service visits and we are there for Wimbledon fortnight annually to ensure the smooth operation of the roof when needed.