
NSF Org: |
CMMI Division of Civil, Mechanical, and Manufacturing Innovation |
Recipient: |
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Initial Amendment Date: | July 26, 2016 |
Latest Amendment Date: | July 26, 2016 |
Award Number: | 1635227 |
Award Instrument: | Standard Grant |
Program Manager: |
Joy Pauschke
jpauschk@nsf.gov (703)292-7024 CMMI Division of Civil, Mechanical, and Manufacturing Innovation ENG Directorate for Engineering |
Start Date: | September 1, 2016 |
End Date: | August 31, 2021 (Estimated) |
Total Intended Award Amount: | $379,999.00 |
Total Awarded Amount to Date: | $379,999.00 |
Funds Obligated to Date: |
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History of Investigator: |
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Recipient Sponsored Research Office: |
526 BRODHEAD AVE BETHLEHEM PA US 18015-3008 (610)758-3021 |
Sponsor Congressional District: |
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Primary Place of Performance: |
Alumni Building 27 Bethlehem PA US 18015-3005 |
Primary Place of
Performance Congressional District: |
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Unique Entity Identifier (UEI): |
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Parent UEI: |
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NSF Program(s): |
Engineering for Natural Hazard, Special Initiatives |
Primary Program Source: |
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Program Reference Code(s): |
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Program Element Code(s): |
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Award Agency Code: | 4900 |
Fund Agency Code: | 4900 |
Assistance Listing Number(s): | 47.041 |
ABSTRACT
As the U.S. population continues to grow in urban communities, the demand for tall residential and mixed-use buildings in the range of eight to twenty stories continues to increase. Buildings in this height range are commonly built using concrete or steel. A recent new timber structural innovation, known as cross laminated timber (CLT), was developed in western Europe and is now being implemented around the world as a sustainable and low carbon-footprint alternative to conventional structural materials for tall buildings. However, an accepted and validated design method for tall CLT buildings to resist earthquakes has not yet been developed, and therefore construction of these tall wood buildings in the United States has been limited. This research will break this barrier by investigating a seismic design methodology for resilient tall wood buildings that can be immediately re-occupied following a design level earthquake and quickly repaired (compared to current building systems) after a large earthquake. Using the seismic design methodology developed in this project, the research team will work with practitioners across the engineering and architectural communities to design, build, and validate the performance of a ten-story wood building by conducting full-scale sub-assembly system testing at the National Science Foundation (NSF)-supported Natural Hazards Engineering Research Infrastructure (NHERI) experimental facility at Lehigh University, followed by full-scale tests at the NSF-supported NHERI outdoor shake table at the University of California at San Diego. This research will enable a new sustainable construction practice that is also cost-competitive, thereby increasing demands for engineered wood production, providing added value for forest resources, and enhancing job growth in the construction and forestry sectors. As part of the research, the experimental programs will serve to provide outreach to the public and stakeholders on issues related to seismic hazard mitigation, modern timber engineering, and resilient building concepts.
The goal of this research is to investigate and validate a seismic design methodology for tall wood buildings that incorporates high performance structural and non-structural systems. The methodology will quantitatively account for building resilience. This will be accomplished through a series of research tasks planned over a four-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 bi-directional testing of building sub-assembly systems, development of a resilience-based seismic design methodology, and finally a series of full-scale shake table tests of a ten-story CLT building specimen to validate the investigated design. The structural systems investigated will include post-tensioned CLT rocking walls in both monolithic and segmental rocking configurations. Implementing segmental rocking walls in a full building system will be a transformative concept that has yet to be realized physically. The rocking wall systems will be investigated under the context of holistic building behavior, including gravity systems and non-structural components. The research team will further push the boundary of existing performance-based seismic design by developing a design procedure that explicitly considers the time needed for the building to resume functionality after an earthquake. With the large-scale testing capacity provided by the NHERI experimental facilities, the design methodology will be experimentally validated, which will at the same time generate a landmark data set for tall wood buildings under dynamic loading that will be available to the broader research and practitioner community through the NHERI DesignSafe-ci.org Data Depot. The project will facilitate implementation of this new structural archetype by interfacing closely with practitioners in the Pacific Northwest interested in tall CLT buildings as a cost-competitive design option. Graduate and undergraduate students, including community college students, will actively participate in this research and gain valuable knowledge and experience, which will prepare them to become leaders in sustainable building practices using modern engineered wood materials.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
The project investigated the lateral-load response of multi-panel self-centering cross-laminated timber (SC-CLT) walls and their interaction with the adjacent building structural components, including the CLT floor diaphragm, collector beams, and gravity load system under multidirectional lateral loading (see figures). In addition, the project investigates the critical connection behavior to accommodate the kinematic conditions imposed by the building's lateral drift response and the controlled-rocking response of the SC-CLT wall under multidirectional lateral loading. The project produced: 1) a conceptual design of the structural components and connection details to accommodate the kinematics conditions imposed by the building's lateral drift response under multidirectional loading without developing damage; 2) fragility functions associated with the probability of damage of SC-CLT walls under unidirectional and multidirectional lateral loading; 3) proposed repair approaches for damaged SC-CLT walls; 4) proposed low-damage connection details; 5) generation of experimental data for calibrating numerical models for seismic performance prediction of tall wood buildings with SC-CLT shear walls; and, 6) an effective multidirectional displacement control scheme for testing three-dimensional large-scale test sub-assemblies with flexible diaphragms.
Research outcomes listed above enabled improved knowledge of the behavior of a full mass-timber building system under multidirectional loading to be acquired. These outcomes enabled design procedures to be developed for enhancing the seismic resilience of mass-timber buildings with SC-CLT walls. Close interactions with the industry during the project, including SmartLam, Western Structures, Simpson Strong-Tie, and Lever Architects have contributed to generating realistic outcomes empowering a faster technology transition to the field. The broad implementation of self-centering CLT walls in tall wood buildings will significantly improve structural safety, resiliency, and sustainability, while reducing costs associated with the construction and repair of structural systems, and the downtime following an earthquake. The project trained one Ph.D. student, three REU students, and three undergraduate students who were involved with the research. Results will be disseminated in one refereed journal paper, four referred conference papers, and presented in various NHERI Researchers Workshops.
Last Modified: 12/29/2023
Modified by: James M Ricles
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