NEESR: Ultra-Low Forced Vibration Testing

California Polytechnic State University Foundation, San Luis Obispo CA

Investigators

Abstract

The research objective of this award is to investigate the feasibility of extremely low amplitude forced vibration testing (FVT) to determine the structural dynamic properties of a low-rise building. To achieve this objective, the researchers will use a very small, 30-pound harmonic load to shake a full-scale, five-story building test specimen, constructed as part of NSF award CMMI-0936505, on the George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES) outdoor shake table at the University of California, San Diego. The results of the ultra-low (UL) forced vibration testing (UL-FVT), namely, the natural frequencies, mode shapes, and damping ratios, will be compared to shake table test results and FVT using much larger shakers. The comparison will be made at multiple stages of the specimen testing. This research is potentially transformative in that it will for the first time define the limits and applicability of the UL-FVT. Data from this project will be archived and made available to the public through the NEES Project Warehouse/data repository at http://www.nees.org. This award will impact earthquake engineering education of K-12, undergraduate, and graduate students and practicing engineers. Verification of the UL-FVT will provide proof of the concept and will serve as a stepping stone to introducing the UL-FVT into university classrooms nationwide. The UL-FVT method will improve structural dynamics education by allowing faculty and students to explore the dynamics of full-scale, real-world structures at a fraction of the time and cost associated with typical FVT. Learning modules will be developed for K-12, undergraduate, and graduate students and archived in the NEESacademy at http://www.nees.org. This work will also advance discovery in the field of earthquake engineering by enabling practicing engineers to verify their linear computational models for both new designs and retrofit applications. This award is part of the National Earthquake Hazards Reduction Program (NEHRP).