Allowing the roof to move, the ends of
each truss are supported on a wheeled bogie
that moves along rails that are fixed to the
new superstructure of No.1 Court. This
superstructure includes five more trusses
that surround the arena, with two of them,
east and west, primarily supporting the
retractable roof.
The east and west trusses are both
80m-long and weigh 490t and 555t
respectively.
These trusses were constructed on
temporary works and the booms were
incrementally welded together to form
the full truss and then laced together via a
bracing structure.
Truss boom sections vary in size, from
8t up to 22t and consisted of CHS sections
ranging in length from 8m to 15m. Stability
and support for the trusses is provided by
eight existing concrete cores and three jumbo
1,083mm-diameter CHS columns, that were
threaded through the stands and founded on
the concrete sub-structure.
Two of these large columns are
positioned either end of the east truss, with
the third supporting one end of the west
truss. A fourth jumbo column could not
be installed as there are ground level water
tanks in the area where this section would
have been founded. Instead a 40m-long
× 11.5m-deep north-west truss had to
be installed, acting as a bridge over the
obstructions and helping to support the
other end of the west truss.
The steel package also included the
installation of some cantilevering steelwork
that will form new hospitality and access
walkways around the upper external levels.
Fixed inner roof elements that adjoin
the east and west trusses were also installed.
This steelwork consists of a plated box
section tension ring with a combination of
tapered plate girders and lattice trusses tying
back to the main trusses on each face of the
structure.
“The tension ring installation required a
combination of pre-welded assembly units
and site welding to complete the ring. This
inner roof structure is then braced using
a mixture of tubular and I-sections,” says
Severfield Project Manager John Calland.
A W A R D SSDA 2019
FACT FILE
Architect: KSS
Structural engineer: Thornton Tomasetti Ltd
Steelwork contractor: Severfield
Main contractor: Sir Robert McAlpine
Client: The All England Lawn Tennis Club
The inner roof serves a number of
functions essential for the implementation
of the No. 1 Court redevelopment. On the
east and west sides, the inner roof contains
the ‘grass nozzles’ which are required to
condition the atmosphere around the playing
surface. They have to be a certain distance
away from the court surface, and this dictates
the extent of the roof in these areas.
Around the rest of the roof, the inner
structure provides locations for gutters to
help drain the roof, a surface for lighting and
air conditioning, as well as helping provide a
weather tight seal against the moving roof.
Summing up, the judges say installing
a moving roof over No.1 Court involved
the adaption of the 1997 building
without interrupting the annual tennis
Championships.
This extraordinarily complex work
was carried out over three seasons with
minimum public awareness. Large movable
steel trusses installed to very exacting
tolerances over the existing building provide
a roof that can shelter a match from rain
within minutes.
NSC 23
October 19
© AELTC/Simon Bruty
/Construction#Temporary_works
/Steel_construction_products#Structural_hollow_sections
/Concept_design#Structural_options_for_stability
/Concept_design#Concrete_or_steel_cores
/Steel_construction_products#Plate_girders
/Construction#Site_welding
/Construction#Tolerances