Site Characterization Using VS30 Per the ASCE 7-22

Value of the Information & Strength of the Argument

The webinar provides valuable, up-to-date information on the new ASCE 7-22 requirements for site characterization, which is crucial for practicing engineers. The argumentation is solid, based on the speakers’ expertise and references to code provisions and research. Stewart clearly explains the rationale behind the changes, such as the lack of physical meaning in time-averaged SPT blow counts and the need to encourage direct VS measurements. He also presents a systematic approach for estimating VS from correlations and handling uncertainty. Cox’s presentation on measurement best practices adds practical value, though the transcript provided does not include his full talk. Overall, the content is well-structured and technically sound.

Scientific Rigor, Source Quality, Title Accuracy

The webinar demonstrates scientific rigor by referencing the NEHRP provisions, ASCE 7-22, and specific research papers (e.g., Borcherdt 1994, Brandenberg et al., Robertson, etc.). The speakers are recognized experts in the field. The title accurately reflects the content. The webinar is a recording of a professional presentation, so it is not peer-reviewed, but the information is consistent with established standards and research. The presence of a brief tribute to Professor Kenji Ishihara at the beginning is not directly related to the technical content but does not detract from it.

The title accurately reflects the content, which focuses on site characterization using VS30 as per ASCE 7-22.

8/10

The webinar is presented by recognized experts (Jonathan Stewart, UCLA, and Brady Cox, Utah State University) and is based on the ASCE 7-22 standard and NEHRP provisions. The content is technical, well-structured, and includes references to research and code provisions. However, it is a webinar recording, not peer-reviewed, and some claims rely on the speakers' expertise.

Markers derived by PSI from the transcript: the creator did not define chapters.

• 02:00Introduction by Maggie Ortiz Milan, EERI director of programs, and overview of EERI.
• 05:00Jorge Meneses introduces the webinar and pays tribute to Professor Kenji Ishihara.
• 10:00Jonathan Stewart begins his presentation on VS30 definition and application.
• 20:00Stewart discusses the historical background of VS30 and the problems with previous approaches.
• 30:00Stewart explains the new site classification system with eight classes and the requirement for VS profiles.
• 40:00Stewart covers methods for estimating VS profiles from correlations with penetration resistance.
• 50:00Stewart discusses VS30 uncertainty and the use of 1.3 factor for site class assignment.
• 1:00:00Brady Cox begins his presentation on best practices for shear wave velocity measurements.
• 1:10:00Cox discusses invasive and non-invasive measurement techniques.
• 1:20:00Q&A session with both speakers.

• NEHRP Provisions (2020) — Referenced as the basis for the new site classification and VS30 requirements.
• ASCE 7-22 — The standard that incorporates the NEHRP provisions and is the focus of the webinar.
• Borcherdt (1994) — Referenced for the original VS30-based site classification and site factors.
• Brandenberg et al. (SPT-based VS correlations) — Referenced for SPT-based VS estimation models.
• Robertson (2009) — Referenced for CPT-based VS correlations.

• NEHRP Provisions (2020) — The webinar is based on the NEHRP provisions, which are consistent with the content presented.
• ASCE 7-22 — The standard incorporates the NEHRP provisions and is the primary reference for the webinar.

• None — No discordant sources were mentioned in the webinar.