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Abstract The utilization of mass timber engineered wood products has increased for new buildings aiming to reduce environmental impacts. Whole-building life-cycle assessment (WBLCA) has been used to quantify the environmental impacts for a building’s lifespan. While mechanisms for calculating the cradle-to-grave impacts of a single building are well established, there are few examples of WBLCA applied for buildings in their first and second life that can be used to inform perspectives and pathways related to the circular economy and lead to informed decision making. This work presents a case study WBLCA to examine the effect of overlapping system boundaries and alternative end-of-life pathways for a building structure in its first and second life. This case study analyzed a ten-story mass timber shake-table specimen that was partially deconstructed and reused as a six-story shake-table building structure. Environmental impacts were analyzed in terms of global warming potential (GWP) calculated as the sum of fossil carbon, biogenic carbon, and avoided impacts. When examining reuse and landfill pathway alternatives using current standards and practices, results show that reusing material causes a positive GWP trend in the first system boundary and negative GWP trend in the second boundary. These results could indicate that it is not advantageous to reuse the ten-story building structure, running against principles of waste hierarchy, although the interpretation should be considered with caution. Future analyses could be improved by considering additional criteria such as demand on forest stocks, economic incentives, and even social impacts for a more complete representation of sustainability. 

Advancements in materials, components, and building systems over the past decade have enabled the construction of taller mass timber structures, creating new opportunities for seismic design in mid- and high-rise buildings. This paper presents a systematic comparison of two full-scale shake table test programs-the 10-story NHERT TallWood and the 6-story NHERT Converging Design both conducted at the University of California, San Diego (UCSD) Large High-Performance Outdoor Shake Table (LHPOST). These projects aimed to develop and validate seismic design approaches for wood buildings in high seismic regions. Both structures employed a self-centering mass timber rocking wall system with distributed energy dissipation provided by U-shaped Flexural Plates (UFPs), enabling direct comparison of structural response and design considerations across different building heights. Despite ongoing innovations, many tall timber buildings still rely on concrete cores or steel braced frames for lateral resistance due to a limited number of code- approved timber systems and an industry preference for traditional solutions. This comparative study highlights the performance of timber-based lateral systems under seismic loading and supports their broader adoption in resilient, mid-and high-rise construction. 

A series of shake table tests were recently conducted on full-scale 10-story and 6-story mass timber buildings at the 6-DOF Large High-Performance Outdoor Shaking Table facility at the University of California San Diego. Stairs, providing the primary egress in and out of a building during and after an earthquake event, were incorporated in each of these building test programs. To ensure they support the immediate recovery of building function, a variety of drift-release details were incorporated. Previous earthquake events and experimental studies have shown that stairs are among the most drift-sensitive nonstructural systems and are prone to damage, therefore relieving interstory drifts is paramount to improving their performance. To this end, the designed drift-release connections within the stairs considered the test buildings response during earthquake motions scaled at various hazard levels with expected minor and repairable damage under large earthquake loading. This paper provides an overview of the shake table test programs from the perspective of the design and performance of resilient steel stairs. 

A test program was designed to answer if it is possible to design and build a tall mass timber building with resilient performance against large earthquakes. Resilient performance was defined as to receive no structural damage under design level earthquake, and only easily repairable damage under maximum considered earthquake. The system under investigation is a full-scale 10-story mass timber building designed and constructed with many innovative systems and details including post-tensioned wood rocking wall lateral systems. Non-structural components on the building were also tested to ensure their damage in all earthquakes are repairable and will not significantly delay the functional recovery of the building after large earthquakes. The tests were conducted using multi-directional ground motion excitations ranging from frequent earthquakes to maximum considered earthquakes. The resultant dataset contains a total of 88 shake table tests and 48 white noise tests conducted on the building at the high-performance outdoor shake table facility in San Diego CA. U.S.A. Data was obtained using over 700 channels of wired sensors installed on the building during the seismic tests, presented in the form of time history of the measured responses. The tall wood building survived all excitations without detectible structural damage. This publication includes detailed documentation on the design and testing of the building, including construction drawing sets. Representative photo and video footage of the test structure during construction and testing are also included. This dataset is useful for researchers and engineers working on mass timber building design and construction in regions of high seismicity. 

Mass timber is a sustainable option for building design compared to traditional steel and concrete building systems. A shake table test of a full-scale 10-story mass timber building with post-tensioned mass timber rocking walls will be conducted as part of the NHERI TallWood project. The rocking wall system is inherently flexible and is expected to sustain large interstory drifts. Thus, the building’s vertically oriented non-structural components, which include cold-formed steel (CFS) framed exterior skin subassemblies that use platform, bypass, and spandrel framing, a stick-built glass curtain wall subassembly with mechanically captured glazing, and CFS framed interior walls, will be built with a variety of innovative details to accommodate the large drift demands. This paper will describe these innovative details and the mechanisms by which they mitigate damage, provide an overview of the shake table test protocol, and present performance predictions for the non-structural walls.