Arup has provided structural engineering, building-services design, and acoustic consultancy for the Unicorn. One of the most striking features of the scheme is that the main auditorium cantilevers out over the entrance foyer and the tower in turn cantilevers off the main auditorium box out over the foyer.
This subtle and complex symbiotic support system has enabled the architect to have a completely column-free foyer space, thereby allowing a dramatic light and free feel to this part of the building. Inside the building, the studio theatre sits directly below the main auditorium and is acoustically separated by a small air gap. To achieve this close proximity, the box-in-box construction of the studio was created using selfcompacting concrete to form the roof slab. As well as the larger structural features, Arup's engineering extended to the in-house technical facilities, such as designing the complex steelwork associated with the support of theatre equipment, scenery flying equipment, technical balconies and lighting bridges with innovative flip-up fl oors. The building consists of a number of primary spaces, each with individual uses requiring a different specific building service to each area. Coupled with this, the theatre needs a very high level of servicing and a high volume of electrical services have to be distributed in relatively constrained areas. The main design challenge for Arup Acoustics has been to accommodate sound integrity for two theatres occupying the same building, one on top of the other. One theatre is basically a concrete box-in-box construction, so that the high sound levels which could disturb the other theatre above are mitigated. As well as the insulation factor, there have been enhancements to allow for high speech intelligibility throughout the theatre spaces.