미 오레곤주, 최초 순수 6층 목조건물 건설 허용 Oregon Becomes First State to Allow Mass Timber Buildings Over Six Stories High

Oregon Becomes First State to Allow Mass Timber Buildings Over Six Stories High

August 24, 2018 Shane Hedmond

Across the United States, any mass timber building designed to be taller than six stories high has to receive special approval from the building codes department.  After a recent addendum was added to the Oregon’s building code, the state has become the first in the country to allow high rise mass timber buildings without receiving any special considerations.

내후성 강재로 보강된 미네아폴리스의 T3 목재 타워 The mass timber T3 Tower, in Minneapolis, is clad with weathering steel./Blaine Brownell

미 오레곤주, 최초 6층 목조건물 건설 허용 미국의 경우 6층 이상의 높이로 설계된 모든 목재 건물은 건축 법규로부터 특별 승인을 받아야 한다. 최근 오레곤주는 건축 법규에 어떠한 보강재도 포함되지 않은 순수한 목재건물 건설계획을 미국 최초로 허용했다. 많은 양의 목재를 사용한 건물과 전통적인 목재 건물을 구별하는 것은 중요하다 환경론자들은 대량 사용된 목재 프로젝트를 선호한다. 이유는 콘크리트보다 더 지속 가능한 제품이기 때문. 대형 목재 빌딩은 또한 비 목재 건물보다 약 45% 더 가볍기 때문에 기초에 대한 하중도 줄일 수 있는 장점이 있다. 목조 건축의 화려한 부활 http://conpaper.tistory.com/68778 황기철 콘페이퍼 에디터 큐레이터 Ki Cheol Hwang, conpaper editor, curator

It’s important to acknowledge the distinction between mass timber and more traditional wood buildings.  Mass timber buildings, like this 12 story building in Quebec, Canada, have heavy duty and engineered wood structural elements, like cross laminated timber (CLT, pictured above). Environmentalists like the idea of mass timber projects, because it’s more a more sustainable product than concrete.  Mass timber buildings can also be around 45% lighter than non-wood buildings, reducing load on foundations.

The new Oregon building code breaks mass timber into 3 classifications:

Type IV A: up to 18 stories high and 270 feet tall

Type IV B: up to 12 stories high and 180 feet tall

Type IV C: up to 9 stories high and 85 feet tall

 

For type A buildings with fire sprinklers, all primary structural frame elements and bearing walls must be enclosed and provide 3 hours of fire resistance and floors must be 2-hour rated.  Type C buildings are permitted to have exposed structural timber as a design element. The standards were developed and adopted from recommendations of the International Code Council’s (ICC) Ad Hoc Committee on Tall Wood Buildings, which was formed in 2015.

“This statewide alternate method intentionally reinforces the notion that the state building code is not a barrier to innovation or any method, technique or material of construction that is supported by scientific findings, while further preserving Oregon’s ability to serve as a single place to obtain statewide approval, providing a predictable regulatory system of business,” the addendum states.

Since Oregon is one of the country's leading timber producers, it's fitting that they would be the first state to approve the alternate construction type. America's "largest" mass timber building, in terms of square footage, was under construction in Oregon last December, but it only stands 5 stories high. It will be interesting to see if and how quickly other states follow in Oregon's footsteps.

Full Addendum: Statewide Alternate Method No. 18-01 Tall Wood Buildings| Oregon.gov

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