ADVANTAGE STEEL SUMMER 2019 | 33 odular construction modular preferences and efficiencies in mind, rather than trying to fit a modular system to a conventional building after the fact. The design must be conceived with modular construction in mind from the outset and must strike a balance between design intent and the production process. An understanding and appreciation for the production process is crucial to discretizing a building into modules and ensuring the design of the modules is efficient from a fabrication perspective, while keeping in mind that standardization is key to increasing PPVC productivity. As well, the architect must be mindful of the modular layout when determining the space planning of the building. Cellular-type buildings such as condo/ apartments, hotels, and student residences are well suited for PPVC. There are also some trade-offs that need to be considered in the overall building design including: • Increase to structural floor assembly thickness and therefore floor-to-floor heights • Double wall construction resulting in thicker wall assemblies (may improve acoustics) • Spans and configurations may be somewhat restricted • Flexibility and adaptability of structure through future renovations becomes more difficult Therefore, it is not uncommon for projects to have a hybrid solution such as a portion of the building that is modular and a portion that is site-built due to programmatic requirements that require longer spans, large column-free areas, or areas that are difficult to pre-assemble in the factory. The actual size of modular units is typically dictated by transportation constraints, on the order of 4,500 mm (15’) wide, 18,000 mm (60’) long, and 3,600 mm (12’) tall, although dimensions will vary depending on the project location and the route from the factory. In addition, the maximum desirable distance for transportation of modules is 400 to 600 kilometres (250 to 400 miles). Furthermore, a prefabricated modular building does not need to look and feel “boxy” or completely rectilinear when complete. A competent and experienced design team can create expressive architecture and varied interior spaces while achieving the benefits offered in prefabricated modular construction. Temporary Conditions All buildings are designed for their final condition. However, PPVC buildings must be designed not only for their final condition but also for forces that each module must withstand during transportation and hoisting. The magnitude and nature of these forces may differ depending on the means and methods used, including pick points and dunnage locations. It is essential to coordinate these temporary conditions with the manufacturer, transport company and erector to ensure modules are designed with adequate strength and stiffness for all conditions they will experience. Materials Modules can be constructed from a variety of different materials including wood framing (both dimensional and engineered), cold- formed steel framing, hot rolled steel, concrete or a hybrid combination of materials. Module manufacturers tend to focus on a particular type of construction material to maximize production efficiency. The choice of material by the stakeholders should consider the specific project requirements including structural force/loading demands and the budget. Structural steel is an ideal choice for PPVC as it is already to a certain extent prefabricated in the shop and assembled/ erected on site. Furthermore, the use of structural steel chassis in PPVC will open or at least expand market opportunities for structural steel as an alternative to cast-in place reinforced concrete for high-rise condominiums and hollow core slabs supported on masonry for low-rise apartment and assisted living facilities. 1.https://www.pcl.com//Meet-the-PCL-Family/Locations/Canada/Toronto/Publications/PCL-Agile.pdf 2.https://www.mckinsey.com/industries/capital-projects-and-infrastructure/our-insights/imagining-constructions-digital-future 3.https://www.mckinsey.com/industries/capital-projects-and-infrastructure/our-insights/reinventing-construction-through-a- productivity-revolution 4.https://www.modular.org/marketing/documents/Whitepaper_ImprovingConstructionEfficiency.pdf