I am a structural engineer. That is to say, I am responsible for designing the primary elements, the bones, of a building to ensure it achieves adequate strength and safety. In my work, I like to pursue opportunities that advance the design of the built environment that range from reducing the environmental impact of construction materials to improving construction efficiency. But implementing projects can be difficult because ingenious structural design is not simply about innovating around a single component, but rather at the core of the building’s system.
Over the past decade, researchers and practitioners across the globe have made incremental advancements in building system technologies that employ large-dimension engineered wood beams, columns and panel elements. Commonly called mass timber, these wood products and systems are allowing designers and builders to create larger scale, higher performing structures for commercial use. The use of mass timber also represents a fundamental shift from the ubiquitous 2×4 stick-framed construction methods associated with residential construction, which are limited in strength and fire resistance. The most recently developed mass timber product is cross-laminated timber (CLT). CLT comprises wood boards that are stacked and glued crosswise to create a single, large unit—a thick, solid timber panel up to 10-feet wide by 45-feet long and 1-foot thick. In the past five years, in many parts of the world, there has been an emergence of schools, libraries, office buildings and apartments that have been constructed using CLT. For urban centers similar to Seattle, mass timber buildings have proven themselves suitable for 8- to 10-storey buildings as well—something unheard of when using conventional stick-framed wood construction.
The primary drivers behind this renaissance of wood construction center on the efficiencies attained through state-of-the-art mass timber fabrication methods, rapid prefabricated construction and reducing the environmental footprint of building materials. Wood is an eminently versatile material: It is easy to cut, connect and transport and can be readily used for beams, columns, floors or wall panels. Coupled with this, wood is a 100-percent renewable resource available locally to us here in the Pacific Northwest and literally made by solar power. In addition, through the growing process, wood biomass actually sequesters a significant quantity of carbon collected from the Earth’s atmosphere.
Over two years ago, architect Joe Mayo and I were studying the global precedent for utilizing mass timber and jointly saw the need to help realize these new building types in Seattle. Deciding to take action, in 2012 we made a presentation to members of the Seattle City Council at their Planning, Land Use and Sustainability Committee meeting. Our presentation conveyed the following: Mass timber buildings are well-suited to help Seattle achieve its goal of increasing urban density in an economical and environmentally friendly way, while also stimulating the state’s rural economy by developing a manufacturing industry around high-value timber products. Our message was well received. Since then, Joe and I have been contributors at the CLT workshop meetings at the Seattle Department of Planning and Development. In the fall of 2013, Seattle formally adopted CLT into the City’s building code, becoming the first jurisdiction in the United States to do so.
Last March, I had the honor of traveling to Washington, DC, to witness the White House and the United States Department of Agriculture (USDA) formally announce that they will support the use and development of innovative, sustainable wood building-materials to protect the environment and create jobs. For designers, the most interesting component of this announcement is that in early September the USDA will launch a national design competition that will award at least $2 million towards a tall wood project that exhibits the architectural and commercial viability of this new mass timber building type.
My study of advanced mass timber systems has indeed affirmed the reality that developing new structural bones for the built environment can be a disruptive process that requires a commitment from all project stakeholders. The good news is that the necessary groundwork is being laid by engineers, researchers and policy-makers—and the Pacific Northwest is poised to lead the nation in implementing these new systems. I’m quite optimistic that our ingenuity will prevail.