The construction of a new performing arts centre for Cheltenham Ladies College.
GCM Contractors was engaged to construct the groundworks and concrete frame for the new performing arts centre.
The project was highly complex from basement to roof level. Oval shaped, patterned, sloping slab soffits & high-class concrete finishes on all elements of the structure from basement to lower roof.
The basement slab alone had more than six different formation levels with slabs varying in thickness from 300mm to 1500mm. The basement retaining wall comprised of a faceted appearance on the inner face and a curved appearance on the outer face.
The stage area of the concrete frame comprised of 6m tall Fairfaced Class C circular and rectangular columns supporting a radius Fairfaced Class B second slab soffit. These columns were constructed using self-compacting concrete due to their height.
The gallery area consisted of very complicated soffit formwork; again, Fairfaced Class B finishes, laid to falls, and curved in alignment. Initial plywood decking was laid then timber furring pieces were individually cut by the carpenters on site to the correct fall in levels prior to placement of a superior grade plywood which was then also cut individually and fixed to a pre-arranged board layout determined by the project architects.
Bespoke expressed joints were then fixed at predetermined locations to the superior grade plywood and bespoke circular recessed formers were fabricated and placed around the tops of the support columns to provide a unique detail at the junctions of the columns into the sloping slab soffits.
The columns within the gallery area ranged from rectangular to circular to bull nosed and were predominantly of Fairfaced concrete. The bull nosed columns were made using bespoke formwork, prefabricated off site from our key supplier.
Separating the stage area from the gallery is the overriding feature of the project; the proscenium wall. This wall was constructed of 6m tall Aluxo tower framework spanning 14m in width. The gallery face of the 3m high proscenium wall was to be Fairfaced Class C finish. The locations of the formwork tie-holes and the plywood panels had to be set out in a predetermined location with the assistance of the project architects to produce an even and patterned arrangement, aesthetically pleasing to the eye.
Similar to the Fairfaced slab soffits, bespoke vertical and horizontal expressed joints were formed by fixing MDF recessed formers to the plywood in locations set out by the architects. The end result was the construction of a superbly finished, reinforced concrete, proscenium wall supported either side from ground floor, 6m below, by two chamfered edged Fairfaced support walls.
The project was a challenge from start to finish due to the unusual shape, high specification finish requirements on the concrete columns, walls and soffits, and restricted site lay down. The project consisted of the following works:
Groundworks:
Bulk excavation.
- Construction of tower crane base
- Reinforced concrete pad foundations
- Reinforced concrete faceted and curved perimeter retaining wall
- Single-sided retaining wall formwork
- Installation of all underground drainage & ducting within the proposed building footprint
- Installation of all underground cast iron drainage under the existing basement slab in Bayshill House
- Importing of fill to make up levels
- External works and finishes
RC Frame
- Construction of the orchestra pit reinforced concrete slab and walls
- Construction of Fairfaced Class C circular and bull nosed 3m tall columns
- Construction of Fairfaced Class C circular & rectangular 6m tall columns using self compacting concrete
- Construction of Fairfaced reinforced concrete walls with expressed joints
- Reinforced concrete lift shaft from basement to roof level.
- Reinforced concrete slabs with Class B Fairfaced soffits, sloping and curved with expressed joints and plywood cut and fitted to predetermined board arrangements
- Construction of six reinforced concrete staircases one with curved half landings.
- Construction of the Fairfaced reinforced concrete proscenium wall, suspended 6m above ground level and spanning 14m in width
