Sacramento Capital Branch - Nov. 29th

ASCE Capital Branch Members and Friends,

Please join us for our monthly presentation led by Dr. Renmin Pretell, Postdoctoral Scholar from UCLA where you will will gain understanding of one-dimensional site response analysis (1D SRA) and how it is utilized to predict ground movement during seismic events.

About the Presentation

Are you interested in learning more about site response analysis?

Do you want to expand your understanding of one-dimensional analyses and how to improve them?

Are you interested in the geotechnical and seismic aspects of engineering?

One-dimensional site response analysis (1D SRA) remains the state of practice to estimate the seismic demands that affect civil structures. However, validation studies continuously show discrepancies between 1D SRA predictions and ground motion recordings. These discrepancies (i.e., residuals) are mainly attributed to (1) errors in the input parameters, and (2) limitations of 1D SRA as a numerical approach. Whereas the former is often addressed in practice, more guidance is needed for the latter.

This presentation describes a methodology that uses increased damping and randomized shear-wave velocity (VS) profiles to reduce and account for mispredictions of linear elastic 1D SRAs. Ground motion recordings from about 500 borehole sites are collected, and the sites are classified as “1D-like” and “3D-like” based on their compliance with 1D SRA assumptions. The data from the 1D-like sites are used to optimize the selection of the increased damping and the amount of VS randomization (slnVs); whereas the data from the 3D-like sites are used to quantify and separate the residuals into systematic and random components. Results indicate that the combined effect of the selected damping and slnVs reduces both (1) the bias associated with linear elastic 1D SRAs, and (2) the variability in site response residuals. The presentation concludes by providing practical guidance for improving site response predictions in routine practice.

About the Presenter

Dr. Renmin Pretell

Postdoctoral Scholar, University of California, Los Angeles

Dr. Renmin Pretell is a Postdoctoral Scholar at the University of California, Los Angeles. He obtained his BS in civil engineering from the National University of Engineering (UNI) in Peru (2012), and his MS and PhD from the University of California, Davis (2019, 2022). Renmin has five years of professional experience, mainly focused on tailings dams and earthquake engineering.