Mass Timber (CLT & LVL)

University of Tasmania Inveresk Student Residences

Client:

University of Tasmania

Architect:

Consortium led by Morrison and Breytenbach Architects

Structural Engineer:

Aldanmark Consulting Engineers

Head Contractor:

Hutchinson Builders

Location:

Invermay Road, Inveresk TAS

Building Methodology:

Mass Timber: XLam CLT (150m3)

Faced with a strict deadline and difficult site conditions, XLam worked with project stakeholders to provide a lightweight and time efficient solution: XLam CLT. Using XLam CLT enabled the construction schedule to be met despite the challenging site conditions caused by the 18-metre-deep silt riverbank.

Overview

The University’s National Rental Affordability Scheme apartments at Inveresk is Tasmania’s first ever multi-storey mass timber residential development. Located on the banks of the North Esk River beside the University’s Inveresk campus, the development comprises of 120 apartments across two three-storey buildings, connected by common social spaces, external landings, and stairs.

XLam was contracted to supply XLam CLT and XLam AirStairs for this project after the University’s Centre for Sustainable Architecture with Wood (CSAW) identified sustainability as a key project objective.

Through the extensive use of timber by replacing less environmentally friendly material such as concrete and steel with XLam CLT and Laminated Veneer Lumber (LVL) support structures, the University was able to achieve the sustainability goals set for the building. The relatively lightweight nature of timber also made it the most suitable material to combat the challenging site condition of the prevailing 18-metre-deep silt riverbank.

This resourceful approach to sustainable prefabricated student apartments received considerable recognition and went on to win the 2016 ATDA Engineered Timber Products Award for an innovative system of sustainable design.

Design & Structure

To improve construction speed to meet the project deadline, the XLam design team and Hutchinson Builders developed a prefabrication enterprise close to the construction site. Here the modular XLam CLT apartments were fully framed, clad, and fitted out in an assembly line process, then delivered to site, stacked, and connected.

This simultaneous production of multiple components of the building, greatly reduced construction times and removed the need for scaffolding.

XLam CLT panels were used for the common room floors, which in turn became the ceilings of the common rooms below, as well as for the walkways interconnecting the apartments and the XLam AirStairs. XLam CLT was sanded and sealed post installation and left exposed on the underside of ceilings and in the stairways and common rooms, to elicit the natural warmth and comfort inherently found in timber.

‘Prefabricated volume modules and CLT connecting floors and walkways, working in combination, were deemed to be the most suitable light weight construction for the prevailing 18m deep silt riverbank site conditions and, in conjunction with the speed of prefabricated construction, were instrumental in making the project feasible.’.

David Bylund, UTAS School of Architecture and Design

Due to the unique fire characteristics of XLam CLT, it was also used as the floor material for all escape routes. The 200mm thick floor panels comprise five layers of Radiata pine lamella and are designed to accommodate substantial fire resistance, which unlike steel remains structurally stable when subjected to high temperatures.

Weighing approximately 20% of concrete, XLam CLT alleviated the challenge of the prevailing 18-metre-deep silt riverbank through reducing the foundation loads and distribution requirements. The flexible nature of XLam CLT modular projects also allows for most components of the building to be dismantled. For instance, the selfcontained modular apartments, modular roof, and wall screen elements can be disassembled and reused in another location.

Outcome

Supplying CLT for the University of Tasmania Inveresk Student Residences, XLam were able to demonstrate the benefits and efficiences of DfMA and prefabrication for large scale mass timber construction projects.

The award winning mass timber design using XLam CLT and XLam AirStairs met all key project drivers including;