Skidmore, Owings & Merrill continues to explore the viability of a timber-and-concrete composite floor system and opens their study to a composite floor system supported by a steel structure.
One reason mass timber construction remains absent from high-rise construction in the United States is because the system remains largely untested in performance and strength. An effort led by Skidmore, Owings & Merrill (SOM) and Benton Johnson, an associate director and structural engineer based in SOM’s Chicago office, has been steadily chipping away at the many unknowns of wood as structure through with its Timber Tower Research Project, which began in 2012 and proposed a hybrid timber-concrete composite system for an existing 42-story building. (The ongoing effort received an honorable mention in ARCHITECT’s 2014 R+D Awards).
Today, the firm released two new studies in its tall timber design and construction research. “Physical Testing Report #1: Composite Timber Floor Testing at Oregon State University” reviews and documents the objectives and setup, protocol, and results of a testing program completed in 2016 on full-scale timber-and-concrete specimens. The second report, “American Institute of Steel Construction (AISC) Steel and Timber System for High-Rise Residential Buildings,” examines whether a system utilizing structural steel columns and beams with a composite cross-laminated timber (CLT) and concrete floor system could be competitive in the high-rise residential market.
“Steel, timber, and concrete each have natural advantages and disadvantages,” Johnson says. “Sustainable structures aim to use a minimal amount of materials and minimize embodied carbon footprint. Hybrid structures use each material where they are most effective, reducing overall consumption. The hybrid/composite approach is often the most economical solution in terms of both cost and carbon footprint. These reports recognize that fact and explore how timber structures can benefit from a composite approach.”