Controlled rocking heavy timber walls (CRHTW) were originally developed in New Zealand as a lowdamage seismic force resisting system using Laminated Veneer Lumber (LVL). This paper examines one way of adapting them to regions of low-to-moderate seismicity in North America, using Cross-Laminated Timber (CLT) composed of Canadian timber species. In particular, the adaptation simplifies the CRHTW by omitting supplemental energy dissipation and minimizing the potential for long-term damage to the timber from the post-tensioning. Key assumptions that are used in the design and analysis stages are evaluated with regard to the difference between timber products, and the structural performance of a prototype CRHTW design is confirmed by nonlinear time history analysis. Despite the lack of supplemental energy dissipation, the prototype design performs well with negligible residual drifts and a median peak roof drift of 0.63%. Future research is identified for the continued development of the adapted CRHTW.
Project contact is Stacey Fritz at Cold Climate Housing Research Center – National Renewable Energy Lab (NREL)
Summary
This project will design, produce, test, and integrate engineered timber products for a modular building system with potential for national applications. The Cold Climate Housing Research Center (CCHRC) in Fairbanks, Alaska, is combining advanced building technologies into a high performance and interoperable kit-of-parts building system called “New Iglu” to meet the increasing demand for affordable, flexible housing solutions. CCHRC is prototyping its innovative New Iglu project, which utilizes vacuum insulated panels, with support from the Department of Energy’s Advanced Building Construction Initiative. With this Wood Innovation Grant, CCHRC will partner with Oregon State University (OSU) and University of Oregon (UO)’s TallWood Design Institute (TDI) to leverage TDI’s specialized research laboratory facilities and expertise in engineered timber, prototyping, and structural engineering. The goals are to prototype modular engineered timber structural frame components for the New Iglu system, demonstrate the commercial viability of low-value timber, and disseminate results to stakeholders. TDI will develop frame components, including reusable structural connections, that integrate with New Iglu and meet current U.S. buildings codes and standards.
The project included product development and materials research. The aim was to produce a wooden façade system with an attractive modern appearance and good constructive design with the help of modern woodworking technology. Important requirements to consider were that the system should have a contemporary, attractive expression and that the façade system should provide a product with high quality ambitions in terms of environmental impact. It should also be flexible and easy to use for architects and designers who want to create unique façades. The main focus in this study was about the visible wood surface appearance where the intention was to create a varied surface with interesting innovative designs, with a method that make it possible to always create new patterns. Two different façade cladding systems were developed by combining woodcraft tradition, new research, digital design tools and industrial processes in the wood construction industry. Prototypes with patterned surfaces on both individual boards joined together and on a system based on multi-layer solid wood panels were tested.
The goal of this work was to develop material quantity estimates of a typical mid-rise office building in the Pacific Northwest and to deliver the results to the Forestry Research Team in the University of Washington (UW) College of the Environment School of Environmental and Forest Sciences. The Forestry Research Team will then use these results to develop regionally specific life cycle inventory data to support the greater study funded by the 2015 McIntire-Stennis Research Grant, which is “to assist small and medium-sized wood products companies and Native American tribal enterprises to understand and adapt to changing market conditions” (http://depts.washington.edu/sefsifr/2015-mcintire-stennis-grantwinners/).
Contemporary design technology has given architects the ability to imagine and visualize complex structures to an extent that is currently beyond our ability to effectively fabricate and build. The described research is intended to mediate between the imagination of the designer and the current modes of construction; this project is part of a larger proposition to use wood as a sustainably sourced material that can be formed, curved and machined to create new digitally produced and tested formations. TimberShell creates prototypes for full-scale timber monocoque structures. Material computation affords us the ability to use the natural bending properties of wood to both bend components into shape and to create a robust load carrying structure once individual wood components are locked in by lamination. The geometry of the shell panel eliminates twisting. The research shows how doubly-curved timber shells that can be applied in either tension or compression. The panels can be used to create and cover spanning structures such as pools, gyms and auditoriums.
Most office building construction relies on steel and concrete for mid-high rise office building applications. The primary goal of this thesis is to understand the implications of CLT and mass timber construction systems for mid-high rise office buildings in Seattle by developing a prototypical office building located on a specific site. This research thesis will focus on comparing this prototypical mass timber office building design to the same/similar design using industry standard construction materials for Seattle. The criteria for comparison will include code, cost, schedule and greenhouse gas emissions.
