New Plymouth girls' high school structural strengthening and upgrading of the 1926 block
Abstract
The building forms the apex of a two-storey L-shaped classroom block, the ‘legs' of the L having been added later and including walls of reinforced concrete. This section was built in 1926 and is of cavity brick construction with reinforced concrete bands provided at first floor and eaves level. Floors and roof trusses are of timber.
The L-shaped block as a whole is not of great architectural importance and the suite of buildings in the school grounds have no consistent architectural form. Consequently, thought had been given to demolishing the 1926 building of the classroom block and replacing its facilities elsewhere in the grounds. However, because toilets and main stairway servicing the L-shaped classroom block
are all located in the 1926 building, it was decided it should be retained.
An initial feasibility study had considered the possibility of tying the 1926 building to the adjacent ‘legs’. Unfortunately, the system of horizontal ties at first floor level would have been seriously interrupted by the stairwell. Furthermore, such a solution relies on the brickwork being able to withstand face loading by spanning without protection between floors.
The 1926 block also contains four classrooms of about 47 m2 each. The total area per floor of the two-storey block is about 250 m2. A lightweight decramastic roof has replaced the former concrete tile roof in recent times.
Inevitably, upgrading of other aspects of an old building are considered once the decision to strengthen the structure is taken. Accordingly, both plumbing and electrical services were upgraded, and the building interior finish was completely redone.
The structural cost was about half the total value of the strengthening/refurbishing operation.
This article concentrates on structural matters.