Nelson Airport Terminal

Entrant: 
Architects: Evžen Novák, Studio Pacific Architecture / Engineers: Dunning Thornton / Construction: Gibbons Naylor

Category: 
10. Innovation timber engineering award

Photographed by: 
Jason Mann

Two strategies were chosen to deliver an environmentally sustainable design for the Nelson Airport terminal building; natural ventilation, and a mass timber structure coupled with a resilient seismic structural solution.

The building takes a simple, but sophisticated approach to achieve natural ventilation for the main terminal space. The buildings plan, height, and roof form are designed to maximise air movement; low-level windows bring air into the building and the carefully articulated roof is split through the centre, creating high-level diamond-shaped clerestory windows that maximise daylight and allow release of warm air through glazed louvres.

Architectural form, scale, and modularity, is achieved through the folded plate roof, which is uniquely achievable through the use of timber; taking a simple "ply box beam" concept and unfolding it to create an architectural form. Radiata Pine was sourced from local plantation forests and manufactured by Nelson Pine Industries Limited (NPIL) into Laminated Veneer Lumber (LVL) and is a significant sustainable aspect of the building. NPIL have calculated approximately 610m3 of engineered timber was used and an estimated 300 tonnes of CO2 are sequestered within the building. The use of LVL timber as structure and form-giver is integral to the aims of the design - a true and tactile response to the brief, that reinforces the materiality and its connection to the surrounding forestry, from which it has been sourced.

LVL structural components - columns, mullions, beams, rafters, and roof diaphragm - were precision cut by CNC machines; allowing all 58 roof ‘triangles’ to be prefabricated in a hangar on airport grounds, to be trucked to the construction site and lifted into place. Prefabrication was a significant benefit to the construction team; reducing time working at height, providing greater quality control, and less disruption due to weather conditions.

The design intent was to minimise materials and maximise the multipurpose nature of the structure. The structural roof diaphragm is faceted to maximise planal strength and exposed internally to express the rhythm of the roof. Use of long-span cross-banded LVL from NPIL, instead of ply reduced joints, provided required stiffness to the roof. A pattern of perforations in the LVL, with acoustic baffle above, also provide noise attenuation for the interior. This product was load tested with the acoustic perforations to confirm design assumptions.

Poor ground conditions required a lightweight structure to be economical, particularly with the internal height. The terminal building was the first implementation of the Tectonus resilient-friction-slip joint, which integrated with the LVL columns to provide a resilient low damage design, in an area with relatively high seismicity and poor ground conditions on the edge of an estuary. As a new innovative structural solution, the Tectonus was tested installed in an LVL column to replicate the final condition. This prototyping gave the team insight into connection detailing and CNC manufacturing capabilities.

Natural ventilation and mass timber structure, coupled with a resilient structural solution, are initiatives that differentiate Nelson Airport and set a precedent for the sustainable design and operation of an airport terminal building.