Carbon12
The building's exterior in 2021
General information
StatusCompleted
TypeMixed-use
Architectural styleNatural building
Town or cityPortland, Oregon
CountryUnited States
Coordinates45°32′53″N 122°39′59″W / 45.54814°N 122.66645°W / 45.54814; -122.66645
Construction started2016
Completed2018
Height85 feet (26 m)
Technical details
MaterialCross laminated timber
Size42,000 sq ft (3,900 m2)
Floor count8
Design and construction
Architecture firmPATH Architecture
DeveloperKaiser Group
Structural engineerMunzing Structural Engineering, LLC
Civil engineerKPFF Consulting Engineers
Main contractorKaiser Group
Known forTallest wood building in the United States
Other information
Parking22 parking spaces
Website
www.carbon12pdx.com

Carbon12 is a wooden building in Portland, Oregon's Eliot neighborhood, in the United States. The eight-story structure built with Oregon-made cross-laminated timber (CLT) became the tallest wood building in the United States upon its completion.[1]

Carbon12 is an 85 ft. (26 m) mixed-use building situated on the corner of North Williams Avenue and 12 Northeast Fremont Street. It was designed, developed, and built by Ben Kaiser of PATH Architecture and Kaiser Group Inc., using CLT panels made by Structurlam.[2] With a rooftop deck, the height is 95 ft. (29 m).[3] Work on the Carbon12 started in July 2016, and it was completed in 2018. It is named after the atomic weight of carbon (12 AMU), as the carbon footprint was one of the primary motivators to choose timber[4] and its street address (12 NE Fremont St.). The Carbon12 building is advertised to be one of the most efficient and environmentally friendly wooden buildings in the U.S.

History

While the use of timber frames for constructing 1-2 story buildings is typical in many countries (see: timber framing), antiquated building codes in the United States discouraged wood frame construction in 5-floor buildings or higher for many years.[5] With the advancement of science, construction technologies and innovation have led to engineered wood products with load capacities stronger than steel[6] and fire resilience beyond those required to meet US building code standards.[7][8] These improved qualities, alongside the historical construction of tall wood buildings in Europe,[5] have led to an acceptance of wood in US construction, and new building codes are being proposed to adjust for this.[7]

The Carbon12 building ran in the USDA's Tall Wood Buildings contest (2014) but did not win the prize.[5] However, Kaieser+Path[9] decided to build it anyway and owned the proposed building site, a competition requirement.[10][11] This building was subject to the 2015 International Building Code (IBC), under Type III-A construction[12] which limits wood buildings to six stories with height 85’ but designers planned for 8 stories, which led to extra time and cost in getting approvals as the City of Portland had never reviewed a tall CLT project before.[11] In the end, City and state officials waived restrictive codes under the IBC section 104.11 for Alternate materials and method requests (AMMR). They were responsible for reviewing the building's structural and safety aspects through a performance-based analysis.[13] Oregon Governor Kate Brown was present when the building reached its peak height. The Carbon12 is acclaimed as a booster for Oregon's timber industry.[1]

Given the rising popularity of wood construction, Carbon12's title of the tallest wood building in the United States is already being challenged by a 148 feet (45 m), 11-floor wood-framing building in Portland, Framework,(USDA winning proposal) under construction.[1]

Building details

The building measures 85 feet (26 m) high for 8 floors, with two ground-floor retail spaces that activate the neighborhood beneath 14 condominium units (2 units per floor). Each unit has a recessed balcony and a dedicated elevator entrance. It has an underground Automated parking system, which is remote controlled that moves cars to their parking spots on a conveyor system.[14] The building employs mass timber, glued laminated timber (glulam), and CLT (cross-laminated timber) in its structural system. Steel is used in the core and for connecting braces, and concrete for the basement, ground floor, and garage (automated garage).[5]

The spacious, 1,600 square-foot wood-filled residences feature floor-to-ceiling glass and light-filled open-floor plans, equipped with seismic alarm technology and spacious patios. There are no shared walls between units that provide a similar acoustic experience as living in a detached single-family home.[15]

Residents of the Carbon12 have given interviews describing the building as "beautiful" and "bright". Few residents were happy with their savings on utilities, commuting expenses, and some residents have also applauded the building's commitment to universal design, which accommodates individuals who are not typically considered in the use of a building and might otherwise find themselves unable to access areas of a structure or their home.[16]

Environmental features

Carbon12 is constructed with sustainably harvested and certified CLT, a renewable structural building material that sequesters carbon and acts as a natural insulator that dampens sound and holds in warmth. 132 tons of carbon were sequestered in the CLT, glulam columns and beams of Carbon12.[17] Additionally, having exposed wood interiors provide biophilic experiences, and timber's ability to char delivers natural fire protection. Furthermore, Carbon12 uses a Buckling-restrained brace frame system to handle an earthquake or other natural disasters.[18][19]

The building's design makes it environmentally friendly, using technologies such as floor-to-ceiling insulated fiberglass windows to reduce thermal bridging and maximize natural daylight. An efficient lighting system using LED lights with remote control systems and sensors for common areas.[15]

The use of solar panels on the roof for the hot water system and exterior lighting reduces damage to the environment by decreasing the amount of fossil fuel needed for the building's domestic, which lowers the amount of greenhouse gas produced and Utility bills.[20] The exterior of the property features clad in vertically striated metal paneling, and a deep cut in façade, drawing light into the central interiors, like a shaft of sunlight penetrating a dense forest.[21]

Carbon12 uses an electric LG Variable Refrigerant Flow system (VRF), an interconnected system that shares the load, making it efficient.[15] The waste produced during the construction process was less due to the modular construction but still recycled and used as biofuel.[22]

Construction

The building was constructed by PATH + Kaiser group from Portland, which also did work on the Radiator building, Oregon (Mass timber building). Munzing structural engineering, LLC provided the best solutions to integrate steel and wood systems in the building.

The primary structure is CLT, which was fabricated at the Structurlam production facilities in Penticton, British Columbia. CLT was made up of many layers of adhered lumber boards stacked at 90° angles for better structural rigidity in both directions. These large panels can be made up to 12 feet wide by 60 feet long. Glulam beams and columns were CNC framed for steel connections based on the CadWork 3D model. Before mass timber was fabricated, Kaiser+Path designed a mini-Carbon12 cross-section to ensure the look, constructability, and mobility. when the mock-up arrived at the site, it was installed and evaluated.[15] Also, It identified the tolerance levels to ensure a tight fit.[23][24] Following excavation and construction of the foundation, a steel frame erected two stories high, to which timber components were anchored. The whole thing was sequenced.[25] Upon truck arrival, Glulam beams and columns and CrossLam panels were lifted by a tower crane directly from the truck bed into position. Each component was labeled and designated for a specific location in the structure. As everything was prefabricated, very few workers were needed, which means less cost, improved safety, better coordination, and added accountability. Construction was quick, and less waste on-site was observed due to its prefabrication and modular installation. Each floor was assembled in five days. CLT is not cheap, but cost savings were made due to construction speed and reduced waste.[22]

Mass timber can be installed in any temperature and weather condition. Still, when it rained almost constantly for a few weeks, breathable SBS sheets were used, and fans circulated warm air to bring the moisture in the CLT down to the acceptable levels.[15]

A combination of materials was used for the acoustic system to meet the code demand of STC and IIC ratings of 60 and above the code minimum of 50 for residential use. So, Kaiser+Path hired multiple subcontractors to install the initial insulation and base layers, another to install the gypsum concrete topping slab, and finally, one more to install the finished floor products.[15]

Carbon12 was built using a design-build approach with the subcontractors for the Mechanical, Electrical, Plumbing, and Fire systems (MEPF). So they were involved in the predesign phase itself, which helped them create a sequencing plan to install their systems without impeding other's work. As the floors were identical, improvements were made as they progressed.[15]

Because the 2015 Oregon building code did not account for tall timber buildings (8 stories), designers showed the building's safety aspects through computer simulations and modeling. Moreover, sensors were placed beneath the building to monitor the building performance.[14]

Recognition and legacy

In Feb 2019, Carbon12 was the recipient of the 2019 Wood Design Awards (Best multi-family wood design) awarded by the Woodworks.[26] In 2017, the building was featured in the Portland business journal and Daily journal of commerce as the year's transformational project.[27]

As Carbon12 was permitted on the special provision, its performance is monitored by the Colorado School of Mines.[28] This engineering data was somewhat useful in making changes in the 2021 IBC code permitting up to 18 stories. The firm is now in the design and research phase for The Spar, which aspires to become the tallest mass timber building globally, with 36 stories and almost 600,000 sq. ft. of office and commercial space.[29]

See also

References

  1. 1 2 3 Oregon pushes for wooden skyscrapers to revive timber industry Archived 2017-09-01 at the Wayback Machine, The Oregonian, 30 April 2017
  2. ↑ "Carbon12 Building for the future". Structurlam. 19 July 2018. Archived from the original on 20 January 2021. Retrieved 16 December 2020.
  3. ↑ kaiser, Ben; Salvin, Kristin (12 March 2020). "The Big Reveal_ How One Firm Built the Tallest CLT Structure in the US". Kaiser group and Path architecture. Archived from the original on 20 October 2021. Retrieved 14 December 2020.
  4. ↑ "Carbon12". Carbon12. Archived from the original on 1 June 2020. Retrieved 15 December 2020.
  5. 1 2 3 4 Garrett Andrews, Wood: the sky's the limit Archived 2017-09-01 at the Wayback Machine, Daily Journal of Commerce, 8 March 2017
  6. ↑ Song, Jianwei; Chen, Chaoji; Zhu, Shuze; Zhu, Mingwei; Dai, Jiaqi; Ray, Upamanyu; Li, Yiju; Kuang, Yudi; Li, Yongfeng (2018-02-07). "Processing bulk natural wood into a high-performance structural material". Nature. 554 (7691): 224–228. doi:10.1038/nature25476. ISSN 0028-0836. PMID 29420466. S2CID 4469909.
  7. 1 2 "What the Fire Service Needs to Know about Tall Wood Buildings". Firehouse. Archived from the original on 2018-11-28. Retrieved 2018-11-21.
  8. ↑ Zelinka, Samuel; Hasburgh, Laura; Bourne, Keith; Tucholski, David; Ouellette, Jason (2018). Compartment Fire Testing of a Two-Story Mass Timber Building (PDF). General Technical Report FPL–GTR–247. USDA, US Forest Services, Forest Products Laboratory (published May 2018). Archived (PDF) from the original on 2018-11-29. Retrieved 2018-11-21.
  9. ↑ "Carbon12". Kaiserpath. Archived from the original on 3 September 2020. Retrieved 12 December 2020.
  10. ↑ "Carbon12 Tall wood prize competition application". Kaieserpath. Archived from the original on 15 January 2023. Retrieved 12 December 2020.
  11. 1 2 "How a small, tenacious team opened the door for American builders to reduce their reliance on concrete and steel in favor of CLT". Building Carbon12. Archived from the original on 1 December 2020. Retrieved 14 December 2020.
  12. ↑ "Codes-standards/building codes". American wood council. Archived from the original on 3 December 2020. Retrieved 12 December 2020.
  13. ↑ Malinowski, Michael F.; Klein, Andrew (2016). "Getting to Yes: Making Effective Use of the Alternate Means Process" (PDF). Archived (PDF) from the original on 24 January 2021. Retrieved 13 December 2020.
  14. 1 2 "Carbon12 case study". RDH making buildings better. Archived from the original on 15 January 2021. Retrieved 13 December 2020.
  15. 1 2 3 4 5 6 7 "New heights in mass timber". Building Carbon12. Archived from the original on 1 December 2020. Retrieved 13 December 2020.
  16. ↑ "Who's moving into the nation's tallest timber building? Portlanders with lofty dreams (photos)". The Oregonian. Archived from the original on 2018-11-28. Retrieved 2018-11-21.
  17. ↑ "Building with wood is a beautiful, sustainable, and impactful way to combat climate change". Building Carbon12. Archived from the original on 1 December 2020. Retrieved 14 December 2020.
  18. ↑ "Carbon12 Structural design and environmental features and". Building Carbon12. Archived from the original on 1 December 2020. Retrieved 15 December 2020.
  19. ↑ Popovski, Marjan; Karacabeyli, Erol (11 December 2020). "Seismic behavior of cross-laminated timber structures" (PDF). Archived (PDF) from the original on 21 January 2022. Retrieved 16 December 2020.
  20. ↑ "Carbon 12 Creates a New Class of Condos". Thinkwood. Archived from the original on 24 January 2021. Retrieved 12 December 2020.
  21. ↑ Hilburg, Jonathan (19 December 2017). "The country's tallest timber building wraps up in Portland". The Architect's Newspaper. Archived from the original on 29 November 2020. Retrieved 13 December 2020.
  22. 1 2 "Construction Process". Building Carbon12. Archived from the original on 1 December 2020. Retrieved 14 December 2020.
  23. ↑ "Concrete tolerances in section 4 of the ACI 117-10" (PDF). American concrete institute. Archived (PDF) from the original on 25 October 2020. Retrieved 12 December 2020.
  24. ↑ "Steel tolerances in section 7.13 of the ASIC 303-16" (PDF). American institute of steel construction. Archived (PDF) from the original on 12 November 2020. Retrieved 12 December 2020.
  25. ↑ Teibinger, Dr.Martin; Matzinger, Irmgard (February 2013). "Construction with cross-laminated timber in multi-story buildings" (PDF). HFA Schriftenreihe (40). Archived (PDF) from the original on 25 July 2019. Retrieved 13 December 2020.
  26. ↑ "WoodWorks Announces 2019 Wood Design Award Winners" (PDF). Woodworks. Wood product council. 28 February 2019. Archived (PDF) from the original on 30 September 2020. Retrieved 15 December 2020.
  27. ↑ "Awards". Kaiserpath. Archived from the original on 4 April 2020. Retrieved 15 December 2020.
  28. ↑ Devlin, Sherry (18 March 2019). "Mass timber: The next great disruption of construction, wood products industries". Treesource. Archived from the original on 1 December 2020. Retrieved 16 December 2020.
  29. ↑ "The Spar". Kaiserpath. Archived from the original on 4 April 2020. Retrieved 16 December 2020.
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