This document outlines the basis of design for the performance-based design and nonlinear response history analysis of the Framework Project in Portland, OR. It is intended to be a living document that will be modified and revised as the project develops and in response to peer review comments.
Performance-based design is pursued for this project because the proposed lateral force-resisting system, consisting of post-tensioned rocking cross-laminated timber (CLT) walls is not included in ASCE/SEI 7-10 Table 12.2-1. Lateral force-resisting systems included in ASCE/SEI 7-10 Table 12.2-1 may be designed for earthquake effects using the prescriptive provisions in ASCE/SEI 7- 10. Lateral force-resisting systems not included are still permitted but must be demonstrated to have performance not less than that expected for included systems. This option is available via the performance-based procedures of ASCE/SEI 7-10 Section 1.3.1.3. Note that lateral forceresisting systems for wind effects are not restricted in ASCE/SEI 7-10. Therefore, design for wind effects will still be approached within the performance-based design framework but in a more state-of-the-practice manner.
Cross-laminated timber (CLT) has become increasingly prominent in building construction and can be seen in buildings throughout the world. Specifically, the use of CLT floor and roof panels as a primary gravity force-resisting component has become relatively commonplace. Now, with availability of the 2021 Special Design Provisions for Wind and Seismic (SDPWS 2021) from the American Wood Council (AWC), U.S. designers have a standardized path to utilize CLT floor and roof panels as a structural diaphragm. Prior to publication of this document, projects typically had to receive approval to use CLT as a structural diaphragm on a case-by-case basis from the local Authority Having Jurisdiction (AHJ).
This paper highlights important provisions of SDPWS 2021 for CLT diaphragm design and recommendations developed by the authors in the upcoming CLT Diaphragm Design Guide, based on SDPWS 2021.
