Pafos Markideion Theatre - The Acoustic Shell

Background
During the initial planning of the Pafos Markideion Theatre it was always the intention to have an Acoustic Shell for deployment on stage. This was to comprise of a back wall with tapered side stage walls and an inclined ceiling sloping down towards the back wall. The layouts of these elements were to generally follow on from the lines set out in the acoustic treatment of the auditorium.

Due to budget constraints the Acoustic Shell was deleted from the initial capital project, to be looked at as additional equipment at a later stage. It was acknowledged that it would be unlikely that there would ever be sufficient funding to incorporate any form of motorisation, with the associated safety elements, for a flown ceiling and that any form of suspension would have to be manually operated; probably incorporated into the existing counterweight flying system.
As Multistage were already supplying and installing the counterweight flying system an amount of preliminary design work on the acoustic shell was carried out following the guidelines set out by the Architect and the Acoustic Consultant.

Design Approach
Whilst the setting out of a folding, suspended ceiling in two main sections seemed feasible; it soon became apparent that the use of traditional, triangular, acoustic towers, with fold out wing panels would not be.

• .The back wall would be a flown framework with the upstage sections of the side stage wall frameworks hinged from the two ends.
• The two downstage sections of the side stage wall frameworks would be hinged-out from the leading edge of the existing Proscenium Towers and would track on and off with them when not in use.
• The two mid stage side wall sections, each incorporating a set of double access doors, would comprise back-braced, frees-standing wagons with a complete winch down top section, enabling it to be stored in the scenery dock.
• The ceiling would require to be split up into two flown sections, one upstage and one downstage.  The upstage, flown section being split into four, individual, swivelling frameworks.  The frameworks would clip into position for vertical storage and be held at the connect inclination by adjustable stay-wires when deployed.
• The triangular profiling and density of the timber cladding required, led to the concept of utilising fabricated aluminium frameworks and suspension trusses in order to keep the weights of the various elements down to a manageable level.
• The intention would be to provide an Acoustic Shell that a minimum of 2 operatives (preferably3) could deploy or store in under 3 hours with only the use of a stepladder.

Construction Design & Fabrication
Subsequently, Multistage were given an order to supply and supervise the installation of the Acoustic Shell having submitted preliminary designs with the tender. Given the overall extent of the aluminium fabrication required, Multistage approached the Total Solutions Group in Birmingham to develop the construction drawings and fabricate all the bespoke frameworks as well as the suspension trusses. The timber cladding would be site-fitted by the same company that had carried out the installation of all the timber work in the theatre, including the acoustic finishes in the auditorium; thus ensuring a perfect match of materials and finishes.

During the design development, using 3D modelling and factory testing, more complex and unforeseen issues were resolved before shipment to site; some of which were.

• Suspension of the back wall from a modified square truss with hanging adjustment to allow for weight compensation after cladding is fitted.
• General usage of "turtle" castors rather than single swivel castors.

• Taking into account the profiling, the whole door sections in the mid stage side wall wagons having to track back off stage to allow the top section to winch down. 
  

• Having the individual frames in each of the flown ceiling sections swivel alternately upstage and downstage of the ladder truss when being stored vertically to balance the weight.
  
• Utilising a substantial "drop-in" bracing frame across the back of the mid stage wagon to help stabilise the two winch sections when travelling.  The same bracing frame being relocated across the top of the doorway, when the wagon is in position, to stabilise the front structure before winching up the top section.
• Addition of small castors to the bottom of each door to allow operation without recourse to a bottom door sill.

Installation in Cyprus was due to start straight after the Epiphany holiday on the 8th January 2017, which would require the equipment to be loaded into a container at Total Solutions ‘ Birmingham works the week before Christmas 2017; not the best timing for local weather conditions, as it turned out.

Installation in Cyprus was due to start straight after the Epiphany holiday on the 8th January 2017, which would require the equipment to be loaded into a container at Total Solutions ‘ Birmingham works the week before Christmas 2017; not the best timing for local weather conditions, as it turned out.

Installation
Previously, during the second phase of the counterweight flying installation, three of the extra sets were supplied with longer cradles to cater for the flying of the back wall and ceiling panels of the Acoustic Shell.
As a result of the factory trial assembly and the use of a 40’ container, many of the elements were shipped out pre-assembled and being lightweight, were quickly unloaded.

The complete side wall structures were erected easily; however it soon became apparent that the counterweight flying set nominated for the suspension of the back wall would be too far downstage and the whole set, including the longer cradle would require moving. Once the counterweight set was relocated and the truss hung, the back wall was assembled and joined to the two side wall frameworks using blind bolts. The completed shell framework was checked dimensionally and then marked up on the stage.

Modifications to the steel frameworks of the existing Proscenium Towers were made to allow the downstage Acoustic Shell frameworks to be permanently hinged from the on stage leading edges and to fold back into the towers, when not deployed, whilst still allowing the towers to track on and off stage as before. An additional, heavy duty, wheeled carrier was added to each of the over stage tracks supporting the towers to compensate for the additional weight.

The completed side walls were detached from the back wall and moved apart to allow the assembly and rigging of the ladder trusses used to suspend the ceiling panels. Once the two ladder trusses were in place the various pre-assembled frames were pinned into position; the panels then being set at the required angle using the pre-installed stay wires.

Once the deployed ceiling units were flown out, the side wall frameworks were moved back into position and the ceiling angle checked against the tops of the wall frames and adjusted as required. The whole Acoustic Shell framework was now ready for the timber cladding to commence.

The cladding work proved relatively easy and progressed quickly; the exception being the mid stage wall frameworks  requiring much more exacting work to cater for the close tolerances for the moving door and top framework sections.

 Each of the mid stage sidewall sections were set back into their storage formats, with the doors retracted and the top sections winched down, to check the clearances with the cladding now in place.  They were then wheeled into the Scenery Dock to check that they would fit into the designated storage areas. No problems were encountered in doing this.

Some last minute concerns about the overall loading imposed when flying the back wall with both upstage side wall frameworks on the same counterweight set, resulted in a decision to store the two side frameworks, separately, flat against the rear structural wall of the stage area. The original hinges between the rear and up stage side frameworks were replaced with new, fabricated, hinges with removable pins.

 A braced, jacking trolley, was constructed on site to facilitate the safe transport of each framework to and from its deployed position to the storage position on the back wall of the stage.

A varnish finish was applied to all the timber cladding to match that used in the auditorium.
Finally, recessed light fittings were mounted in the ceiling panels and wired back, via flexible cables clipped on the ladder trusses, to dimmer circuits on the fly gallery.