IN THE CONTEXT OF LAND SCARCITY AND GROWING URBAN POPULATIONS, EARLY PLANNING AND ENGINEERING SMARTS HAVE A ROLE TO PLAY IN THE DESIGN OF PREFABRICATED BUILDINGS FOR LATER (MOSTLY VERTICAL) EXPANSION, WRITES SIMON MCCARTHY , SENIOR STRUCTURAL ENGINEER, WALLBRIDGE GILBERT AZTEC.
Intelligent design that factors in the need for future growth and adaptability is an increasingly critical driver for engineers and designers; rapidly changing demand and end-use requirements mean adaptability at a manageable cost can create a real point of difference in the value of a building’s lifecycle.
“One effective way in which the adaptability of prefabricated buildings can be facilitated is through the provision in footings for additional floors at a later stage. This approach is particularly relevant where inner city schools have no room to expand in terms of land space. However, catchment areas have increasing numbers of families and students moving into these areas, due to old single dwellings making way for the development of medium density and high density housing.”
“One effective way in which adaptability of prefabricated buildings can be facilitated is through the provision in footings for additional floors at a later stage. This approach is particularly relevant where inner city schools have no room to expand in terms of land space. However, catchment areas have increasing numbers of families and students moving into these areas, due to old single dwellings making way for the development of medium density and high density housing.”Simon McCarthy, Senior Structural Engineer, Wallbridge Gilbert Aztec.
By planning for future stages, additional floors can be added to an existing modular building with relative ease, as long as the provision for the additional weight and effect of lateral earthquake and wind loads are accounted for in the initial design. Stair wells can easily be extended. Lift shafts can also be extended, although it should be noted that this requires collaboration with the lift manufacturer.
This can be difficult to achieve during the design phase because manufacturers are hesitant to commit to a design until they are commissioned. Allowance for water and energy supply also needs to be considered at concept design stage for the additional building services required to support an increase in occupancy levels.
Several existing buildings in Melbourne have recently received additional floor levels through the careful adoption of lightweight framing, to make construction at height achievable and to minimise expensive strengthening works on existing footings and shear walls. This includes the use of light gauge steel framing or CLT assembly to the top of concrete framed buildings. Utilisation of modular configurations at concept design stage will provide consistent floor weights and avoid disjointed load paths or transfer levels to achieve an efficient structure.
The provision for additional floors is also highly relevant for other building projects such as prisons, or aged care. Correctional facilities can utilise large tracts of land; provision to expand the accommodation component of prisons without additional land space would provide enormous cost benefits to the community.
Aged care is another area of the building market that is expanding quickly. A good example of the utilisation of space for aged care is the new 19 storey serviced apartment building in Albert Road, South Melbourne. The layout of accommodation rooms for aged care can be designed in a manner highly suited to reap the benefits of modular / prefabricated construction techniques, and the reduced construction time from adopting Prefabricated Prefinished Volumetric Construction (PPVC) methods would have created a more favourable outcome for the client than conventional construction.■