Nambour Hospital Shade Structures

This Project was entered in the LSAA 2013 Design Awards (Cat 3, 3351)

Essentially the purpose of the project was about cost effective space creation.

The tensioned awning is positioned over a deck area on the first floor at the Nambour children’s hospital. The Hospital is located on the side of a steep incline, the deck is located in an elevated position.

The awning-covered deck now allows children recovering from surgery or illness to play outdoors on the deck in supervised shaded conditions. Previously children were confined to an internal hospital playroom.

Children, parents and staff using the facilities refer to the structure as the (Sydney) ‘Opera House’ – Not a bad comparison given this project was built on a shoestring financial budget.

PROJECT DESCRIPTION:

Using Monotech HDPE shade fabric, the project represents a ridge and valley tensioned awning canopy. Creating the ridge and valley form and contrast in height (3 high curved rafters, 4 low curved rafters) achieved a cost effective bold and colourful dramatic form.

The structure is 19.37mts in length and 8.0 mts wide. The undulating curved rafters at the front of the structure range in height from 4.3 mts to 3.0 mts. The tensioned awning canopy attaches to the building by a linear edge sail track at a height of 4.2 metres.

The structural steelwork is powder coated for rust protection. The support columns double in function by acting also as structural supports for the attached glass balustrade maintaining clean design lines for the overall visual effect of the project.

DESIGN / FABRICATION / INSTALLATION BRIEF

The project represents an authentic Light Weight Structure with the ratio of structural steel to surface area of the fabric canopy being 11.2 kg per sqmt of fabric.

When the project was given to our company cost was the driver for the development of the project. Typically when meeting this criterion a barrel vault style structure would be developed to most cost effectively create functional under canopy space.

Bored with barrel vaults and a standard for creating shade, our design and engineering team manipulated the barrel vault form by lifting three of the rafters and lowering four of the alternate rafters, creating a contrast in height, and achieving a wow factor in design with very little increase in construction costs!

Cost effective space creation with a dynamic aesthetic was the overall result for the project.

The distinct ridge and valley form adds vibrancy and colour to the overall building facade.

The challenge in installation was building the project while the hospital was in full operation.

STRUCTURAL SYSTEMS

Our design engineer took into consideration the site orientation, prevailing weather direction and site location.

The structure faces north east. The design wind criteria for the site is Region B, terrain category 2.5 recurrence interval 1/500 design wind speed 51.9mps (strength) in accordance with AS1170.2-2002.

AS1170.2-2002 was used for determining Cp values for the ridge and valley fabric canopy profile.

Being 19 metres long and 8 metres wide the tensioned awning canopy attaches to the building by a linear edge sail track at a height of 4.2 metres. The undulating curved rafters at the front of the structure range in height from 4.3 metres down to 3metres.

The support columns are chemically anchored to the suspended concrete slab.

The support columns double in function by acting also as structural supports for the attached glass balustrade maintaining clean design lines for the overall visual effect of the project.

MATERIALS

Monotech HDPE shade cloth was selected due to the dimensional stability of the fabric. The structure is in an exposed elevated position and is subjected to severe storm events. The stability of the Monotech fabric results a shade cloth canopy that does not need to be retensioned over time. Furthermore the design of a ridge and valley profile delivers strength to the canopy form.

Monotech HDPE shade cloth was chosen due to the Designers history with the fabric and the fabrics ten year warranty. Tenara thread was used for the sewn seams, offering a fifteen year warranty on stitching.

The structural steelwork is powder coated for rust protection.

FABRICATION

A folding plan for the fabric canopy was supplied due to the installation of the canopy at height with limited access.

Our company’s role was exclusively design and engineer – apart from supplying a folding plan and installation advice our company was not involved in the fabrication of the project.

COLLABORATION, CONSTRUCTION AND MAINTENANCE

The project needed to be built while the hospital facility was in operation. Due to the site location beside a narrow roadway a crane was required to lift the steel to the deck area for installation. Elevated work platforms were also lifted in the area for the installation process and then removed when the structural steel work was in position.

The structure is minimalist. The fabric hugs the rafters there are no exposed horizontal services to gather dirt and dust. The project is situated beside a busy road, so some environmental pollution will gather on the fabric, as the fabric is porous shade cloth naturally occurring rainfall is suitable in cleaning the exterior of the fabric. The internal structure is at an accessible height for monthly general cleaning with a hose and wipe down of vertical structural steel.

As a barrier to a children’s play area, the glass balustrading would require daily cleaning.