4 Projects That Embraced Hybrid Construction With Stunning Results
Wood is a sustainable, high-value building material that can contribute to a project’s sales proposition while appealing to a new generation of eco-minded employees, residents and occupants. While wood structural systems can be a smart choice for many buildings, a hybrid structural approach that combines materials like wood with concrete or steel is sometimes the most effective way for developers to meet budget, project timeline, sustainability and aesthetic goals.
Hybrid projects utilizing mass timber and light-frame systems can be prefabricated off-site, which can reduce construction time on-site and, consequently, lower labor costs. Mass timber buildings can be roughly 25% faster to construct than concrete buildings and require 90% less construction traffic. Since mass timber panels are prefabricated and then assembled on-site, buildings made from mass timber have much shorter project timelines and safer construction sites.
Wood is a natural, renewable and sustainable material for building, with a lighter carbon footprint than steel or concrete. According to the American Forest Foundation, steel and concrete consume 12% and 20% more energy, emit 15% and 29% more greenhouse gases, release 10% and 12% more pollutants into the air, and generate 300% and 225% more water pollutants than wood, respectively.
By implementing hybrid systems, developers who may be new to building with wood can explore its positive influence on a building’s environmental impact.
Perhaps most importantly from a tenant perspective, wood is aesthetically pleasing.
“Wood gives Mother Nature fingerprints in our buildings,” Michael Green said at TED2013.
Wood is often left exposed in hybrid projects because it doesn't need to be wrapped or bolstered to meet code requirements. This can help people feel connected to nature, and, as Vox put it, “There is nothing quite so beautiful as large expanses of exposed wood.”
Continue reading to learn more about four projects constructed using a mass timber hybrid approach.
Billie Jean King Main Library - Long Beach, California
The Billie Jean King Main Library in Long Beach, California, is a 93.5K SF structure named after the tennis legend. This striking building was constructed with glass, wood and steel, including an exposed glulam roof system over steel framing.
Mass timber is a visual and structural focal point of the building, comprising 80% of the structural material, with over 1 million board feet of glulam used throughout. The building’s envelope is composed of an aluminum and glass curtain wall, and the library also features floors constructed with glulam girders coupled with plywood decking, creating a warm aesthetic and lighter load atop the concrete garage below.
Along with its impressive facade and bright, airy features, this building was also able to achieve LEED Platinum certification, thanks to its timber construction, rooftop photovoltaic cells, daylighting strategies, controlled air ventilation system, and extensive glazing with architectural overhangs for solar protection.
Carbon12 - Portland, Oregon
Carbon12 is an eight-story mixed-use residential building in Portland that is named after the atomic weight of carbon — 12 amu — and its street address, 12 Northeast Fremont St. This was once the tallest mass timber building in the U.S., constructed from a glulam post-and-beam frame with cross-laminated timber floors and ceilings.
The building is anchored in a concrete foundation and two-story steel core with prefabricated CLT panels comprising the remaining multi-story structure. This hybrid project also embraced the prefabricated construction model: CLT panels were transported to the site and fitted into place with a crane.
“In my 30 years of building, I have not seen a building framed as quickly and efficiently as Carbon12,” said Scott Noble, senior project manager at Kaiser Group + Path Architecture.
In addition to sustainably harvested and certified CLT, Carbon12 features other green building attributes, including natural daylighting, highly efficient mechanical systems, rooftop solar panels, and state-of-the-art earthquake monitoring and alert systems.
80 M Street - Washington, D.C.
Originally built in 2001, 80 M Street was among the first office buildings in what would eventually become the Capitol Riverfront District. In 2019, Columbia Property Trust filed plans to vertically expand the building to accommodate new tenants. Architecture firm Hickok Cole set out to not only create more space but also build something that would help it stand out from its competitors. To accomplish this, the firm chose mass timber for the 100K SF overbuild — a first of its kind for the city and the design team.
“We wanted to bring something new to the market, something that would set the space apart,” said Thomas Corrado, senior associate and senior project designer at Hickok Cole. “We’re a concrete city, so we wanted to see how we could introduce mass timber into the D.C. marketplace as a viable building system.”
The design team chose mass timber for its light weight since the existing building could not handle the load of a traditional concrete overbuild. The lobby was also redesigned to incorporate new wood elements and upgraded amenities, and the building will feature exposed CLT ceilings and glulam beams, columns, arches and trusses. Some of the new wooden elements include products from a variety of species, including Douglas fir, spruce pine fir, Southern yellow pine, hern fir and Alaskan yellow cedar.
Sonoma Academy Commons - Santa Rosa, California
Sonoma Academy is a private, independent college preparatory high school in Sonoma County. This two-story, 19.5K SF space features a unique Y-shaped design crafted from locally sourced building materials. Sonoma Academy’s hybrid design system features a steel structure with a Western red cedar roof and exterior terrace soffit, constructed of CLT panels made from 100% Forest Stewardship Council-certified wood. The choice of prefabricated mass timber also helped the project meet a tight construction schedule. A small crew assembled the prefabricated roof in just two days.
Along with its unique hybrid structure, the building has sustainable features that include a green roof with outdoor space for the high school’s students and employees, as well as a classroom, garden, park and gallery area. Sonoma County-based craftspeople provided many of the construction materials, which reduced transportation costs while supporting the local economy. The project achieved LEED Platinum certification and is seeking Zero Energy Certification, WELL Education Pilot and LBC Petal certification.
To see more demonstration projects, visit the Think Wood Project Gallery.
This feature was produced in collaboration between Studio B and Think Wood. Bisnow news staff was not involved in the production of this content.
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