LATBSDC Workshop 2023-1
Selection and Modification of Ground Motions for Engineering Design
When: April 18th, 2023, 11:00AM-1:00PM
Where: USC Tower, Room 1501M (1150 S. Olive Street, Los Angeles, CA 90015).
Physical attendance is limited to 40 participants. Online attendance via Zoom is limited to 100 participants.
The workshop is free for the public for attending either in person or online. Prior Registration is required.
About this Workshop
The goal of this workshop is to present and discuss various methods of selection and modification of ground motions for analysis and design of structures. The intended audience are practicing engineers and graduate students.
For many years, amplitude scaling and tight spectral matching have been the most common options. These two options, define the two ends of the spectrum of choices, and are no longer the only options available. The Mean Spectrum Modification Method (MSM) is becoming the standard of practice for nonlinear analysis of building structures. The MSM procedure modifies the frequency content of the ground-motion suite to ensure that the average of the spectrum resultant closely matches the design spectrum at all periods. Since the matching is done at the spectrum-resultant-average level, the required modifications are small compared to the conventional method of spectrally matching every individual component of each record. This process significantly reduces the higher-mode amplification effects frequently present in the usual amplitude scaling method.
MSM maintains both record-to-record variability as well as period-to-period variability. In addition to matching a target average spectrum, the procedure can also be extended to achieve a target spectral acceleration standard deviation versus period as well. New methods of ground-motion selection will also be presented.
About the Workshop Speaker
Dr. Silvia Mazzoni's academic studies have focused on the design and behavior of reinforced concrete structures. She started her research in the field during her undergraduate studies at UC San Diego with Prof. MJ Nigel Priestley, and continued with Prof. Steve Mahin and Prof. Jack Moehle during her PhD studies at UC Berkeley, which completed in 1997. After one year working with Prof. John Wallace at UCLA, Silvia joined the OpenSees Development team at UC Berkeley as the user-support manager. In this role, she developed valuable documentation and the OpenSees Days program, making OpenSees accessible to the engineering community. In 2010 she joined the New Technologies Group at Degenkolb Engineers, where she was tasked with developing their ground-motion and hazard capabilities. In 2013 she joined the Next Generation of Ground-Motion Attenuation (NGA) program, now at UCLA under the leadership of Prof. Yousef Bozorgnia. Her focus is on the management of the databases and support projects. She is currently in several BSSC Issue Teams focused on improving the code implementation of ground-motion selection and modification, as well as nonlinear analysis approaches. Having reduced her university appointment to part time, Dr. Mazzoni is now working on several self-funded projects such as Silvia's Brainery -- an on-line academy on earthquake engineering courses focused on knowledge and understanding -- and developing software for ground-motion selection and modification, as well as OpenSees User Interfaces. All these efforts have the goal to make nonlinear response history analysis more accessible to all engineers.