Collaborative Research: Seismic Resiliency of Repetitively Framed Mid-Rise Cold-Formed Steel Buildings

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The need for low cost, multi-hazard resilient buildings constructed of sustainable, low-carbon footprint materials is urgent. Mid-rise buildings framed from thin-walled, cold-formed steel (CFS) have the ability to support this urgent need. The potential benefits of CFS-framed structures include low installation and maintenance costs, high durability and ductility, lightweight framing, and a manufacturing process using recycled material. In addition, consistency in material behavior, high strength-to-weight ratio and stiffness, and use of a non-combustibile material are added benefits compared with other lightweight framing solutions. By using framing schemes with closely-spaced vertical members repetitively placed in the walls, CFS buildings develop lateral resistance through strap, sheet, or sheathing attached to these vertical members. The response of these building systems under earthquake loads and, in particular, the contribution of portions of the building system not specifically designated by the design engineers to resist earthquake loads are not well understood. This award will undertake a series of experiments and complementary numerical modeling to characterize the relationship between the designated lateral force resisting system, i.e., the shear walls, and the complete CFS building system response, including the impact of the gravity walls, finish materials, and interior partitions, during seismic events. Taken in totality, this project will contribute to the nation's welfare by advancing fundamental understanding and design methodologies for CFS building systems vulnerable to extreme natural hazards. The research plan involves an integrated collaboration among the University of California, San Diego (UCSD), Johns Hopkins University, and relevant industry organizations. The research team will conduct education and outreach to a diverse group of middle and high school students and teachers and integrate, into the project activities, high school, undergraduate, and graduate student researchers to help train the next generation workforce. The seismic resistance of repetitively framed structures is unique due to the large overstrength and the significant contribution of non-designated systems in the lateral response. In this project, a set of experiments de-constructing the building into wall lines and separate components will be conducted to provide unique information in understanding benchmark full-scale shake table tests. The shake table tests will be conducted on the NSF-supported Natural Hazards Engineering Research Infrastructure (NHERI) Large High Performance Outdoor Shake Table at UCSD. Using these experiments, for the first time, all major components of nonlinearity will be captured in complementary numerical building models that, when validated, will form the basis for wider seismic studies and evaluation. Project data will be made available in the NHERI Data Depot at https://www.designsafe-ci.org/.