Search for: All records

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. 

This project contains imagery collected from uncrewed aircraft system (UAS) flights over three barrier islands, Fort Myers Beach (FMB), San Carlos (SC), and Sanibel Island (SI), that are near Fort Myers, Florida, following Hurricane Ian. These barrier islands had substantial impacts from the hurricane, including the destruction of many residences and infrastructure, coastal degradation, and other environmental impacts. The imagery here was collected using a low-flying fixed-wing UAS with a high-resolution camera system that simultaneously collected oblique and nadir images from five lenses. The raw data set is very comprehensive and very dense. The extent of the collected data can be seen in the Hazmapper map. The data was processed into 3D models using structure from motion. The resulting 3D models have amazing damage detail and are measurement quality. They can be used to fully characterize damage to buildings, infrastructure, and the natural environment. The complete models are available here, with one model developed for each UAS flight (18 total flights). However, the complete models are very large data sets and require significant GPU power to open and manipulate. Thus, the data set is also divided into “tiled” areas on a 300-meter grid. Each tiled area is provided in both a full-resolution 3D model and a reduced-resolution preview that can be used for quick inspection. The tiles are named and distributed as shown here: https://arcg.is/19TLr5. The abbreviations for Fort Myers Beach (FMB), San Carlos (SC), and Sanibel Island (SI) are used throughout. The data set was collected and processed by the NHERI RAPID Facility and was part of the deployment by the Structural Engineering Extreme Events Reconnaissance Network (StEER). 

This Grant for Rapid Response Research (RAPID) project will collect and analyze perishable data on historical buildings. The Tumwata Village (formerly known as Blue Heron Paper Mill Site) located by the Willamette Falls in Oregon City, Oregon, has a very intriguing history and was recently purchased by the Confederated Tribes of Grand Ronde with the intent to restore the falls to their natural state and preserve some of the oldest structures. The site presents a unique opportunity to perform rapid investigations to collect and analyze perishable data on these historical buildings and develop new knowledge in the area of building assessments in corrosive environments. This industrial site contains a wide range of structure types (steel frames, concrete frames, timber frames, masonry walls and massive concrete walls) that were built over a period of 150 years and that employ many construction details that are common in older structures. The data collected and the results of the research will be applicable to many buildings in coastal communities throughout the country. Lidar data sets collected from these buildings will support the development of new methods to analyze and synthesize large data sets as well as integrate visual observations and material testing to quantify structural deterioration damages. The challenge in developing artificial intelligence (AI) technologies to find and quantify damage in structural systems using lidar data is the need to train the methods on existing data sets that show a wide range of damage states. The data to be collected from this site will provide an extensive training data set relevant to structural components common to older buildings. Development of such AI technologies for fast identification and quantification of damage would be transformative for the natural hazards research community and would expand the ability to learn from archived lidar datasets. The collected dataset will be available to researchers to serve as high quality training data in algorithm development. 

 

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. 

During extreme events such as earthquakes, stairs are the primary means of egress in and out of buildings. Therefore, understanding the seismic response of this non-structural system is essential. Past earthquake events have shown that stairs with a flight to landing fixed connection are prone to damage due to the large interstory drift demand they are subjected to. To address this, resilient stair systems with drift-compatible connections have been proposed. These stair systems include stairs with fixed-free connections, sliding-slotted connections, and related drift-compatible detailing. Despite the availability of such details in design practice, they have yet to be implemented into full-scale, multi-floor building test programs. To conduct a system-level experimental study using true-to-field boundary conditions of these stair systems, several stair configurations are planned for integration within the NHERI TallWood 10-story mass timber building test program. The building is currently under construction at the UC San Diego 6-DOF Large High-Performance Outdoor Shake Table (LHPOST6). To facilitate pre-test investigation of the installed stair systems a comprehensive finite element model of stairs with various boundary conditions has been proposed and validated via comparison with experimental data available on like-detailed single-story specimens tested at the University of Nevada, Reno (UNR). The proposed modelling approach was used to develop the finite element model of a single-story, scissor-type, stair system with drift-compatible connections to be implemented in the NHERI TallWood building. This paper provides an overview, and pre-test numerical evaluation of the planned stair testing program within the mass timber shake table testing effort. 

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.