General View of the Link@Langley Roof

Large ETFE Structure - 2024DA - Link at Langley Atrium

2024 LSAA Design Awards Entry #4866 Link at Langley

IDENTIFICATION NUMBER	4866
ENTRY CATEGORY (1-6)	4 – Glazing & Vertical Structures
ALTERNATE CATEGORY (1-6)	3 – Large Structures
ENTRANT ROLE	Designer / Engineer / Fabricator / Installer
PROJECT NAME:	Link@Langley ETFE Atrium
APPLICATION OF PROJECT:	Clear ETFE ‘glazed’ Atrium Roof over a commercial redevelopment

Citation Large Link at Langley

PROJECT DESCRIPTION:

The Link@Langley ETFE Atrium not only enhances the visual appeal of the riverside redevelopment but also demonstrates the successful fusion of modern lightweight glazed roof design with practical engineering solutions.

The result is a harmonious blend of form and function and a symbol of innovation, seamlessly integrating into its surroundings while offering a captivating architectural aesthetic. This project exemplifies the power of clever design and cutting-edge materials in shaping the future of urban architecture. Massive in size and scope, the Link@Langley ETFE Atrium structure is 65 meters long and 40 metres wide and sits atop a former office building between seven and eight storeys above the atrium floor.

THE PROJECT

Nestled along the picturesque Perth riverside, the Link@Langley ETFE Atrium stands as a testament to lightweight structure innovation and design excellence. This custom-designed, 1665m² single-layer ETFE canopy crowns the central atrium of a revitalised shopping, dining, and entertainment district, transforming the former Fortescue Metals HQ into a contemporary urban hub.

The architectural vision for the Link@Langley ETFE Atrium was clear (in more ways than one). The clear purpose was to create a visually striking, yet functional feature glazed skylight element to enhance the appeal of the riverside redevelopment. The aesthetic vision was to have a visually clear atrium roof, to create a sense of open sky, while still protecting patrons and visitors from the elements.

We worked closely with the project architect to design the Link@Langley ETFE Atrium, a structure that truly reflects the aspirations of Lightweight Structures. The innovative use of lightweight ETFE film as the glazing materials helps to minimise the amount of supporting steel, even over the large unsupported central spans. The ultra-light material has also allowed for greater design freedom, with the undulating shape of the canopy mimicking the fluidity of a breaking wave.

STRUCTURAL SYSTEMS

Massive in size and scope, the Link@Langley ETFE Atrium structure is 65 meters long and 40 metres wide and sits between seven and eight storeys above the atrium floor.

Our initial design challenge was to seamlessly integrate the canopy structure with the existing buildings, providing a light, transparent and waterproof atrium for the new entertainment precinct. We were extremely limited in locations where support columns and braces could be fixed back to the original structures, which dictated some of the design and geometry decisions.

Even with the ultra-lightweight ETFE cladding, the massive area covered by the atrium structure uses 74 tonnes of structural steel. Fixing steel to existing structures required detailed loading analysis to avoid damaging the buildings.

Using parametric modelling software, we designed a full 3D model of the ETFE structure, including the surrounding buildings, to test the loading on anchor locations and to confirm the HD bolt set-out points. The fixing points were an interesting design and install challenge, with 80% of the canopy affixed to the roof (floating slab) of the former Fortescue Metals HQ, while the other 20% of connections required vertical fixing points to the adjoining Hyatt hotel.

MATERIALS

ETFE is durable, highly transparent, and extremely lightweight in comparison to glass structures (upto 20x lighter than a glazed roof). This modern membrane is quickly becoming the material of choice for large, glazed atrium applications.

ETFE is not only a lightweight and durable material but also an environmentally friendly choice. This incredibly lightweight material requires far less supporting steelwork than a more traditional glazed roof. This translates into an overall embodied carbon saving for the building, due to greatly reduced usage of construction materials. The high transparency of ETFE allows for natural light penetration, reducing the need for artificial lighting and thereby lowering the energy consumption of the atrium. In addition to low material weight and high light transmission benefits, the production of ETFE film has a low environmental impact, and the material is fully recyclable, aligning with modern sustainability standards.

For the Link@Langley, we proposed a single layer ETFE printed with a 16mm silver-dot frit pattern (P46D16) on the underside. Print and shade factor was carefully evaluated to both provide thermal comfort to the atrium but also to ensure guests in the hotel rooms above would still have good visibility down into the space below.

Fabricating the unique shape of the Link@Langley required detailed plotting and welding plans. The 3D shape of the ETFE atrium was achieved by welding 72 individual panels into seven separate sections of ETFE.

The seven ETFE sections range in size from 99m² to an enormous 355m²section across the widest part of the canopy.

The structure was finished with custom-designed Zincalume steel gutters around the entire perimeter and downpipes connecting into exiting stormwater drains.

INSTALLATION

A tower crane was used to raise the prefabricated steel sections to the Level Seven rooftop. Once the steel skeletal formwork was installed, we progressed to ETFE installation. The ETFE panels are supported by almost 200 stainless steel cables, threaded through specially designed and fabricated cable pockets welded to the underside of the ETFE. The cables are attached to the steel rafters and then tensioned to create a solid exoskeleton to support the membrane.

Installing tensioned membrane panels eight storeys in the air over an open void required a highly experienced rigging and installation crew.

THE RESULT

The ETFE Atrium will enhance the overall visitor experience to the Link@Langley development by creating an inviting and comfortable environment. The transparent canopy allows for an abundance of natural light, making the space feel open and airy while providing protection from the elements. Visitors can enjoy the beauty of the riverside setting in a controlled climate, adding to the appeal of the shopping, dining, and entertainment district.

The completed Link@Langley ETFE Atrium is a stunning addition to the Perth riverside, exemplifying the principles of lightweight structures by employing modern new materials in traditional architectural applications. By replacing glass with ETFE film, this project optimises construction material usage and stands as a model of modern architectural and engineering excellence.

COSTS

Confidential