BIM and Digital Design: A Closer Look at How Mass Timber goes from Factory to Building Site
Le Corbusier’s fascination with the automobile is evident in the architect’s various photographic records of him posing proudly next to a car in front of his architectural work. According to the Franco-Swiss architect, in addition to enabling more efficient and economical construction, the industrialization of architecture could form the basis of improved aesthetic results in the same way the modern car chassis supports the creative and modern design of the automobile body. Yet, while vehicles have experienced impressive changes since the 1930s, it can be said that architecture has been slower to adopt the advances of other industries.
But that has been changing little by little. Driven by concerns around sustainability, the use of non-renewable fossil resources, and efficiency, coupled with accelerating demand to build new buildings and more accessible infrastructure, the construction industry has been incorporating numerous new technologies, including those adopted from other industries. In addition, renewable materials such as wood have been identified as an ideal construction material—especially when incorporating innovative mass timber products such as CLT and glulam, design methods and processes like BIM and DfMA, tools for visualization such as VDC, and tools for manufacturing such as CNC. We know, these are a lot of acronyms, but we will try to clarify them throughout this article.
Design for Manufacture and Assembly (DfMA) is a design approach that focuses on both ease of manufacturing for the product parts and the simplified assembly of the final product. It combines two methodologies; Design for Manufacture and Design for Assembly. That is, from the initial stages of creation, decisions are based on avoiding problems during construction and improving efficiency.
This is an approach used across many industries, and in construction it is particularly well suited for mass timber using products like cross-laminated timber (CLT) or glue-laminated timber (glulam). This is because, when designing and building with mass timber, the construction itself is much more an assembly of parts, and is quite different from the design and construction of more traditional construction. Mass timber panels, beams and columns are manufactured offsite and transported to the construction site, prefabricated with all the stops and holes for accommodating the predefined installations, including MEP (mechanical, electrical, and plumbing). For the process to be smooth from beginning to end, it is essential to organize starting from the initial stages of the project, allowing diverse teams to connect early on to contribute to the final product, avoiding delays and setbacks at the construction site.
It is at this point that Building Information Modeling (BIM) helps a lot in the process. BIM refers to a set of technologies, processes, and policies that allow various stakeholders to collaboratively design, build, and operate an installation in the virtual space, forming a reliable basis for decisions throughout the life cycle of the building, from first ideas to demolition. In other words, for any project to flow efficiently, it is important that everyone speaks the same language—BIM. It allows for the visualization and simulation of all parts of a work, providing an understanding of the assembly and feasibility of modeled solutions. It also supports a shared understanding of the design solution through the 3D model, which can facilitate cooperation among the project team and eliminates the risk of common errors in the interpretation of 2D drawings. Combined with this, the model can be exported to several other programs for structural and thermal analysis, and can also generate files for machining by Computer Numeric Control (CNC) machines.
Ideally, a well-defined organization chart for the project, with all those responsible for each area receiving and returning with their contributions, help make the project flow seamlessly, leading to smoother manufacturing and construction. In a nutshell, this means that, once the architect has the initial design complete, structural and installation engineers should already be involved to pre-launch their parts. The project then returns to the architect for elaboration of further details. In each of the design stages, the entire design team is involved, including those responsible for the manufacture of parts or those in charge of assembly; these disciplines must be well-defined and detailed. It is observed that the use of BIM during the design stage reduces the time required to convert architectural drawings into manufacturing drawings and improves coordination between the design team and external manufacturing facilities, which is vital to the success of the construction.
The 18-story Brock Commons Tallwood House, at the University of British Columbia (UBC), is an example of a successful case. In this project, Virtual Design and Construction (VDC) was intensively used to support the analysis of design and construction among the various teams in this complex project. BIM also describes the properties of each of the different building elements (connected to an extensive database), with the creation of a virtual project prototype that can have its performance simulated and tested. VDC is a subset of BIM focused mainly on the geometric 3D representation of an installation. The VDC model facilitated planning and communication in various aspects of the design, pre-construction, and construction phases, because it provided a comprehensive, accurate, and highly detailed representation of the construction.
In the case of this project, as described here, a VDC model was developed from the beginning of the project, covering all construction elements from the structure to the interior finishes to the mechanical and electrical systems. The process was comprehensive, and all details and services were included in the model. This model helped with decision-making during the development of the project, and allowed the modelers to work closely with the design team, promptly incorporating iterations and design updates, notifying the team of any problems or conflicts that needed to be resolved, and ensuring that the model was always accurate and detailed in its representation of the project.
During pre-construction, the VDC model was important for the creation of a prototype of two floors of the building, to test the solutions developed for the project and the construction’s viability. The VDC model was also the basis for the manufacturing model that was used directly by the CNC machines and for the tension tests of the CLT panels.
A carefully planned and integrated project, with proper organization, will lead to a much faster construction. In the case of this 18-story building, the wooden structure was completed less than 70 days after the arrival of the first prefabricated components at the site, which represents a significant saving of time and, consequently, of money for construction. More time in design, less time in construction. This is a promising scenario, especially if we consider the use of renewable materials, in this case wood.
Read more about the potential impacts of BIM and Mass Timber construction in this report from the BIM TOPiCs Research Laboratory at the Universiry of British Columbia.