Mott Macdonald and BFLS work together to build The Royal Welsh College of Music and Drama
Cardiff's Royal Welsh College of Music and Drama comprises an acoustically excellent 450 seat concert hall, a 180 seat theatre, four rehearsal studios, an exhibition gallery, foyer areas, a terrace overlooking Bute Park and a new café bar. The two performance auditoria were designed from the inside out, so the starting point was to achieve acoustic excellence.
While the architecture and acoustics define the internal space, engineer Mott MacDonald had to contain, support and service this with discretion. The concert hall walls and lid are of thick in-situ concrete and acoustically isolated from the rest of the building with a clear gap. The outer accommodation and roof - which both include a further acoustic wrap to the hall - are entirely separate, providing excellent sound barriers around the hall.
All conduits, ducts, pipes and fixings were detailed to minimise auditoria penetrations and mitigate noise breakthrough. Plant room equipment was acoustically treated to prevent vibration and large diameter ducts treated with baffles are used to reduce air velocity and keep noise inaudible. Conditioned air is fed between the auditoria steps, an energy efficient and quiet system. To eliminate electrical ‘hum', all lighting control gear is located outside the acoustic envelope of the auditoria.
The steel roof structure weighs around 45kg/m2. Long external cantilevers are counterbalanced by large internal spans, and a deep perimeter truss matches the architectural profile. The slender 30m south roof tip cantilevers 15m beyond a single, tapering, hollow steel column. Achieving this was complicated as the shape of this section of the roof tends to both lift and twist in the wind. Mott MacDonald prevented this by designing a diamond-profile truss to provide torsional rigidity, enabling the roof to retain its slender dimensions. The sleek design extends to the top of the roof, which was kept plant-free through a ‘bottom-up' building services strategy.
Mott MacDonald introduced building information modelling (BIM) by developing a 3D structural model that integrated the architectural and building services designs. Early development of this model reduced design change risk and accelerated the design programme. As each discipline refined its own component of the project, the central structural model was updated. This enabled any ‘clashes' to be detected and rectified very quickly, and no re-design due to co-ordination issues was needed during construction.
The project architect was BFLS.