Project contact is Hongmei Gu at the Forest Products Laboratory
The FPL team is in charge of developing a full comparative LCA study for three multiple-story mass timber buildings and their concrete alternatives in the U.S. Northeast region, with Boston as the point location. Using these three comparative LCAs, this research will determine the GHG emissions reduction potential from mass timber use in the building sector for the U.S. region. This may increase potential for growth in wood utilization, timber harvest, and forest management practices through the market demands.
This thesis explores the challenges and potential of mass timber as a paradigm shifting technology for the building industry through the application of parametric modeling technology to the design of office buildings. By testing building configurations in three zoning envelopes—low-rise suburban, mid-rise urban, and high-rise urban—optimization strategies for mass timber office buildings were developed. Facades and floor slabs were identified as the primary contributors to building cost and environmental impacts and therefore the easiest targets for optimization. The primary method for optimizing facades is replacing curtain wall with solid cross laminated timber (CLT) walls, this method runs counter to developer driven standards of fully glazed facades making short term adoption of this strategy unlikely without major shifts in building developer and owner expectations. Slabs and floor systems can be optimized through the implementation of novel solutions that take advantage of composite action between glulam, CLT, and concrete elements. Additionally, zoning height incentives could be used to make timber construction competitive with steel and concrete systems despite increased floor-to-floor heights. Finally, future research opportunities and needs, both architectural and technical, are identified.
Project contact is Shiling Pei at the Colorado School of Mines
NHERI Tallwood project is an effort to develop and validate a resilient-based seismic design methodology for tall wood buildings. The project started in September 2016 and will last till 2020. The project team will validate the design methodology through shake table testing of a 10-story full-scaled wood building specimen at NHERI@UCSD. It will be the world's largest wood building tested at full-scale.
Seismically resilient, lateral systems for tall timber buildings can be created by combining cross laminated timber (CLT) panels with post-tensioned (PT) self-centering technology. The concept features a system of stacked CLT walls where particular stories are equipped to rock against the above and below floor diaphragms through PT connections and are supplemented with mild steel U-shaped flexural plate energy dissipation devices (UFPs). Experiments were conducted to better understand rocking CLT wall behavior and seismic performance. The testing program consisted of five single wall tests with varying PT areas, initial tensioning force, CLT panel composition, and rocking surface and one coupled wall test with UFPs as the coupling devices. The walls were tested with a quasi-static reverse-cyclic load protocol. The experimental results showed a ductile response and good energy dissipation qualities. To evaluate the feasibility and performance of the rocking CLT wall system, prototype designs were developed for 8 to 14 story buildings in Seattle using a performance-based seismic design procedure. Performance was assessed using numerical simulations performed in OpenSees for ground motions representing a range of seismic hazards. The results were used to validate the performance-based seismic design procedure for tall timber buildings with rocking CLT walls.