Friday, June 5
1:00 – 2:00 pm | Redefining the Computation-Mechanics Nexus in Large-Scale 6-DOF Shake-Table Testing
Joel P. Conte, Ph.D., P.E., F. EMI, F. ASCE
Distinguished Professor Eric and Johanna Reissner Endowed Chair
Department of Structural Engineering
University of California, San Diego
Abstract: The UC San Diego Large High-Performance Outdoor Shake Table (LHPOST) was commissioned on October 1, 2004, as a shared-use facility under the U.S. National Science Foundation (NSF) Network for Earthquake Engineering Simulation (NEES) program. Although originally conceived as a six-degree-of-freedom system, budget constraints led to its initial construction as a single-degree-of-freedom table. After 15 years of operation, it was upgraded to its intended 6-DOF capabilities between October 2019 and April 2022 and renamed LHPOST6.
A multi-physics model (digital twin) of the LHPOST6 was developed. Under bare-table conditions, the model integrates three subsystems: (1) hydraulic dynamics, (2) pneumatic (nitrogen-precharged) hold-down struts, and (3) three-dimensional kinematics and dynamics of the mechanical components, including the platen and actuators. A methodology was established to calibrate model parameters and validate the model using acceptance and characterization test data.
For loaded-table conditions, a coupled dynamic model was developed by integrating: (a) the MTS 469D table motion controller, (b) the LHPOST6 model in Simulink, and (c) nonlinear structural specimen models in OpenSees. A numerical solution algorithm was formulated for the resulting nonlinear equations of motion. The model was validated against two full-scale experiments: the 10-story mass timber building tested in the NHERI TallWood project and the 6-story mass timber building tested in the NHERI Converging Design project. We explored the long-standing, powerful concept of model-based controller tuning to improve ground motion tracking using a numerical model of the shake table-specimen-controller system, thereby reducing the risk of damaging high-value test specimens during tuning.
The presentation will highlight and discuss key aspects of the model, its validation, and potential applications in large-scale shake table testing.
Biosketch: Joel Conte received his Civil Engineering Diploma in 1985 from the Swiss Federal Institute of Technology in Lausanne, Switzerland, and his M.S. (1986) and Ph.D. (1990) in Civil Engineering from the University of California, Berkeley. He is currently a Distinguished Professor of Structural Engineering at the University of California, San Diego, where he holds the Eric and Johanna Reissner Chair in Applied Mechanics and Structural Engineering. Before joining UC San Diego in 2001, he served on the faculty at Rice University (1990–1997) and UCLA (1998–2001). He is a Fellow of the ASCE Engineering Mechanics Institute (class of 2018) and a Fellow of ASCE (class of 2025). He is also a Fulbright scholar (class of 2006).
Professor Conte's primary research interests include structural modeling and analysis; earthquake engineering and structural dynamics; random vibrations; structural reliability and risk analysis; probabilistic performance-based analysis and design; shake table dynamics and control; experimental-analytical correlation studies; structural identification; Bayesian inference and calibration of mechanics-based structural models; and structural health monitoring. He has published over 300 papers in international journals and conference proceedings.
Professor Conte was a member of the design team for the Large High-Performance Outdoor Shake Table (LHPOST) at UC San Diego, developed as part of the NSF George E. Brown Network for Earthquake Engineering Simulation (NEES). He served as Principal Investigator for the NSF-funded project to upgrade the LHPOST to six degrees of freedom (2018–2022) and was Director of the UC San Diego Englekirk Structural Engineering Center (2011–2023), which houses the NSF Natural Hazards Engineering Research Infrastructure (NHERI) LHPOST6 shake table experimental facility.