Structural Steel Towers Installed to Shore the Defective Reinforced Concrete Ring Beam Supporting the Auditorium Roof Framing of Seton Academic Centre, Mount Saint Vincent University, Halifax, NS
J.W. Cowie Engineering Limited was retained by Mount Saint Vincent University to investigate the excessive downward deflection of the reinforced concrete ring beam supporting the auditorium roof of Seton Academic Centre.
The flat roof area over the auditorium was ponding water and the moveable wooden curtains used to divide the auditorium into four lecture theatres were jambing. The area of the water ponding was over the concrete ring beam in question and the movable wooden curtains were suspended from the concrete ring beam.
Cowie's investigation revealed the ring beam had inadequate strength and stiffness. Temporary structural support was required. Cowie prepared structural design drawings and specifications for two structural steel towers for support of the ring beam. The structural steel towers extend from the underside of the ring beam, through the auditorium floor with bearing on a structural steel grillage mat placed on top of the basement concrete floor slab. The underside of the basement concrete floor slab was grouted to prevent settlement.
After the structural steel towers were installed, the concrete ring beam was jacked up by the use of hydraulic jacks with steel shims installed between the underside of the concrete ring beam and the top of the structural steel towers. The concrete ring beam was jacked up sufficient height to prevent jambing of the moveable wooden curtains. The steel support towers interfere with the view of the stage when the curtains are withdrawn providing a theatre in the round as per the original design.
Cowie developed permanent structural restoration design alternatives to provide support and/or strengthening of the defective ring beam without the use of internal supporting towers thereby avoiding disruption of the view of the stage when the moveable wooden curtains are retracted permitting the auditorium to be used as a theatre in the round.