MODULAR CONSTRUCTION WITH LOW-GRADE HARDWOOD CROSS-LAMINATED TIMBER

Abstract

In this paper the author evaluates the results of a design-build project that employed the use of prefabricated, modular construction with cross-laminated timber (CLT) panels custom-developed from local, low-grade hardwood (Yellow Poplar, Liriodendron tulipifera). The American Institute of Architects award-winning project is the first permanent building in the United States to be granted a building permit for, and complete construction with, hardwood CLT. The paper presents and evaluates the attainment of each of the following research objectives in the design-build process and includes a review of the mechanical and structural testing underpinning panel performance. The project's research objectives included: (1) the development of locally-sourced, pressed, and utilized hardwood CLT that mechanically outperforms commercially available softwood CLT; (2) the development of low-carbon project logistics that allowed for all design and construction steps - from wood harvesting to CLT layup and utilization - to occur within a 3-hour driving radius of the project site; and (3) the development of prefabricated, modular construction workflows for the project's structural, exterior-exposed hardwood CLT. The 10-meter-tall hardwood CLT project was completed, passed all inspections, and opened to the public in 2021.