Page 54 - Special Awards Issue 2016 Green Builder Magazine

DESIGN FUTUREFOR A SUSTAINABLE

CLT CORE

Tall Timber Rising CLT PANEL-TO-PANEL
CONNECTOR
Architects and builders are looking EXTERNAL POST-TENSIONING
to wood as a sustainable alternative ELEMENT
for mid-rise construction.
CLT PANEL JOINTS
CONCRETE MAT FOUNDATION

BY JULIET GRABLE CLT CORE CREDIT: LEVER ARCHITECTURE
GLULAM BEAM
THE COUNTRY’S FIRST mid-rise wood buildings will soon
be going up, one on each coast. These buildings will rely GLULAM COLUMN
on mass timber construction, a category that includes CONCRETE MAT FOUNDATION
engineered beams, or glulams, and the less familiar cross-
laminated timber panels. CONTINUOUS CLT DECK
CLT is made by gluing several layers of dimensional lumber GLULAM BEAMS BELOW
together. Each layer is oriented at right angles to the previous one;
the opposing grain structure provides strength and resistance to CONCRETE MAT FOUNDATION
shear. CLT is well suited for floors, walls and roofs in mid-rise
buildings. Mass timber elements are durable and fire resistant, All Wood. The Framework building in Portland, Oregon, will
and because they are assembled in a factory, they speed up include a CLT core surrounded by a post and beam glulams,
construction. Manufacturing them is much less energy intensive system, which will support continuous CLT decks.
that manufacturing steel and concrete—in fact, wood buildings
sequester carbon. FRAMEWORK | STR

CLT has been used in Europe for 25 years, and recent technological www.greenbuildermedia.com
developments and have enabled taller and taller buildings to be
constructed with CLT and other engineered wood members. There
are now examples of “tall timber” buildings around the world,
including Canada.

In this country, increased demand for mass timber products hold
the potential for reviving rural economies, especially if communities
can create value-added products close to the harvest site.

The USDA is betting on this strategy. In 2014, the agency, in
partnership with the Softwood Lumber Board and the Binational
Softwood Lumber Council, announced the U.S Tall Wood
Building Prize Contest, in which teams were invited to design
structures which “showcase the safe application, practicality and
sustainability of a minimum 80-foot structure that uses mass
timber, composite wood technologies and innovative building
techniques.” The USDA awarded $1.5 million grants to each of
the two winning projects—one designed for Manhattan; one for
a neighborhood in Portland, Oregon. The money is intended to
help teams finance the necessary testing and engineering required
for the mass timber elements, which will ultimately help create
demand for them.

52 GREEN BUILDER Special Awards Issue 2016