BBC Night Garden Live Theatre
The project involved the design, manufacture and installation of a unique inflatable, portable theatre to house the "In the Night Garden Live" show, a stage version of the popular BBC Television children's program that will tour the UK including London, Glasgow and Birmingham.
The theatre is made up of four inflatable structures: an entrance lobby, an auditorium, a backstage area and a link tunnel that measures more than 66m long by 37m wide when assembled. The inflatable entrance lobby has ample room for merchandising, a food and drink area and toilets (including baby changing facilities).
The auditorium incorporates the stage and raised, theatre-style seating. The backstage area provides storage room for props and costumes in addition to space for the performers to change. The entrance lobby and auditorium are linked by an inflatable tunnel that incorporates extra connection points for the addition of other inflatable structures, if required, at a later date.
The four structures have identical connecting door openings so they can be installed in a variety of configurations to suit the available space at each location on the tour.
The show's creators wanted a structure that could be transported easily and erected quickly while providing approximately 14,000 square feet of space for an entrance lobby, auditorium and backstage area. The auditorium needed to have sufficient space for 13 rows of raised theatre seating and a stage and could not have any supporting columns that would spoil the view for the audience.
In addition to the normal lighting used in stage productions, the show would extensively use projected images covering the entire visible surface of the interior of the auditorium. The material used in the construction would have to be capable of producing sharp, high intensity images when projected onto. The auditorium needed to block out all natural light to achieve the maximum impact with the lighting and projections, but the entrance lobby needed to use as much natural light as possible.
The main challenge was determining the optimum shape for the theatre so it could provide the space required while being structurally sound without any internal columns or supports. Several shapes were analyzed before choosing the ellipsoidal forms of the entrance lobby and auditorium.
The next step involved choosing the optiumum thickness for the inflatable walls to provide sufficient rigidity without being unduly heavy. This required extensive use of finite element analysis in conjunction with analytical techniques developed for predicting membrane loads and deflections in inflatable structures.
Tectoniks pressurization systems are already compact and quiet in operation. To reduce noise levels still further the valves used to connect the inflation hoses were modified so air entering the walls of the structures was not audible.
The inflatable structures are constructed using a combination of welding, stitching and sealing to produce a virtually airtight structure requiring little power to pressurize. Air pressure is monitored by an automatic control system also designed and built by Tectoniks. Despite 52mph winds and flash flooding in Liverpool, the structures have performed flawlessly and there has been no disruption to the shows.