With global urbanization trends, the demands for tall residential and mixed-use buildings in the range of 8~20 stories are increasing. One new structural system in this height range are tall wood buildings which have been built in select locations around the world using a relatively new heavy timber structural material known as cross laminated timber (CLT). With its relatively light weight, there is consensus amongst the global wood seismic research and practitioner community that tall wood buildings have a substantial potential to become a key solution to building future seismically resilient cities. This paper introduces the NHERI Tallwood Project recentely funded by the U.S. National Science Fundation to develop and validate a seismic design methodology for tall wood buildings that incorporates high-performance structural and nonstructural systems and can quantitatively account for building resilience. This will be accomplished through a series of research tasks planned over a 4-year period. These tasks will include mechanistic modeling of tall wood buildings with several variants of post-tensioned rocking CLT wall systems, fragility modeling of structural and non-structural building components that affect resilience, full-scale biaxial testing of building sub-assembly systems, development of a resilience-based seismic design (RBSD) methodology, and finally a series of full-scale shakingmore »
From Testing to Codification: Post-tensioned Cross Laminated Timber Rocking Walls
Wood buildings in North American has been predominantly constructed using light-framed wood systems since early 1900’s, with only limited exception of heavy timber construction in some non-residential applications. This situation is likely to change in the future with the growing acceptance of mass timber construction in the region. In fact, a number of mass timber buildings have been constructed in recent years in the U.S. and Canada, including low- to mid-rise mixed-use buildings (e.g. UMass Student Center, T3 building) and tall towers (e.g. Brocks Commons at UBC). Most of these buildings utilized cross laminated timber (CLT) or nail laminated timber (NLT) floors and heavy timber framing systems to support gravity loads, and a non-wood lateral system such as concrete shear walls or a braced steel frame to resist wind and seismic loads. Although CLT material and glulam products have been recognized in the U.S. and Canada (IBC (2018) and NBCC (2015), there is currently no mass timber lateral systems in the U.S. and only one system (platform style panelized CLT shear wall) in Canada that is currently recognized by the building codes. As a result, special design procedures and review/approval processes must be followed for any building intended to use more »
- Editors:
- Blass, Hans
- Award ID(s):
- 1635156
- Publication Date:
- NSF-PAR ID:
- 10221630
- Journal Name:
- Proceedings of the International Network for Timber Engineering Research (INTER)
- Sponsoring Org:
- National Science Foundation
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Drywall partition walls (DPW) could considerably affect the seismic resilience of tall cross-laminated timber (CLT) buildings due to cost and building downtime associated with repair. These drift sensitive components are susceptible to damage at low shaking intensities, and thus controlling or eliminating such damage in low to moderate earthquakes is key to seismic resilience. Conversely, post-tensioned CLT rocking walls have been shown to be a resilient lateral load resistant system for tall CLT building in high seismic areas. A series of tests will be performed at the NHERI Lehigh EF to compare the performance of DPWs with conventional slip-track detailing and alternative telescoping slip-track detailing (track-within-a-track deflection assembly), and to evaluate different approaches for minimizing damage at the wall intersections through the use of gaps. Moreover, a configuration is examined with partition wall encapsulating the rocking wall for fire protection. This paper presents a summary of pre-test studies to design the best configuration of DPW to improve the overall resiliency of the structure.
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