Modular construction is on the rise. Some clear benefits to modular construction are that it’s faster and safer than on-site construction, allows for better quality control, and it’s much easier on the environment. Modular construction can reduce construction time by 50%, cost by 20% and on-site waste by up to 90%. Modular construction has the potential to completely change how we construct buildings.
Modular construction isn’t limited to low-rise buildings. How are high-rise buildings built using modular construction? What are the barriers to wide-spread adoption of this method?
Game-Changing for High-Rise Construction
The modules used in modular construction have a form that works well for modular construction – essentially a long rectangle. Modular construction of high-rise buildings generally consists of volumetric units that are the size of each room and essentially stacked like building blocks. Modular construction of high-rise builds differs from low-rise mainly in the use of steel framing versus wood framing.
Two main methods of constructing the modular units are loading-bearing and corner-supported. With load-bearing, the loads are transferred through the side walls. Corner-supported modules transfer their load from edge beams to corner posts.
With the first, the compression resistance of the walls is the controlling element, with the second, the compression resistance of the corner posts. The double insulated walls of load-bearing modular buildings bring increased acoustic insulation and fire resistance.
With smaller modular buildings a few stories high, it makes sense to have every module be the exact same – they all carry similar loads. With a building 20 stories or higher, this no longer makes sense. The bottom modules need to be much stronger to carry a larger load than modules at the top. By designing the top modules to be lighter than the bottom ones, money and materials are saved.
Still Have a Ways to Go
Applications of modular construction for high-rises are limited, despite the clear benefits. Less than one percent of high-rise buildings around the world are built using modular construction. The tallest modular high-rise is Collins House in Melbourne, Australia, which is 60 stories high.
The United States is behind most developed nations in modular high-rise construction innovation and advancement. Only two buildings in the entire country are above 20 stories.
Researchers with the University of Melbourne and the University of Sydney reviewed innovations in modular construction and how they could apply to high-rise construction – along with some of the barriers. They also discussed developing design guidelines since those missing guidelines are a barrier to wide-spread adoption.
According to them, the limited use of this method for high-rise construction is likely due to “a lack of strong structural systems and joining techniques to ensure structural integrity, overall stability, and robustness of an entirely modular building.”
In response to these limitations, the reviewers identified areas of study that could help overcome some of the limitations. These include “(i) developing a composite module with lighter and stronger structural members, (ii) developing a smart joining technique with higher strength and stiffness and easy to install, (iii) developing a computationally efficient computer tool for advanced analysis and daily design of modular tall buildings, and (iv) developing design guidelines for accelerating the real world application of modular construction.”
The writers of the review believe that this research would benefit all areas of modular construction – not just for high-rise construction. They concluded the paper by stating: “By resolving technical challenges, modular buildings can be built taller with the new composite modules, faster (and cheaper) with the smart joining technique, safer with new design pro-visions, and more efficiently with computationally efficient tools.”