Date of Award

5-2024

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Civil Engineering

Committee Chair/Advisor

Dr. Nadarajah Ravichandran

Committee Member

Dr. Ronald D. Andrus

Committee Member

Dr. Weichiang Pang

Committee Member

Dr. Brady A. Flinchum

Abstract

This dissertation presents the development of earthquake hazard generation software, CarolinaShake and CarolinaADRS, for the state of South Carolina and its applications in the field of earthquake engineering. South Carolina is a seismically active state in the eastern United States, and there is a need to accurately quantify the earthquake hazard and incorporate it into the design of infrastructure systems. To achieve this objective, the South Carolina Department of Transportation (SCDOT) is actively supporting the initiatives to update its seismic design policies and procedures of civil infrastructure systems. As part of those initiatives, first, CarolinaShake, a Windows-based graphical user interface (GUI) software, is developed by incorporating the seismic hazard results of South Carolina for various return periods and site conditions, i.e., hard-rock and reference outcrop. The capability of selecting and screening the earthquake time histories from multiple databases and also generating synthetic time histories based on the South Carolina regional geology conditions are incorporated. Then, the software is updated with capabilities of spectral matching and scaling of earthquake time histories to match the desired site-specific seismic hazard. Additionally, various visualization capabilities, output files, baseline correction techniques and ground motion parameters are also added. The developed software serves as a ground motion development tool for site response analysis and dynamic analysis of structures for the SCDOT.

Further, ground motion characteristics using different types of earthquake time histories and spectral matching algorithms are analyzed and compared to choose the suitable combination of the type of time history and spectral matching technique for South Carolina. Then, the effect of the number of spectral points in the uniform hazard spectrum on the modified time histories and performance of spectral matching algorithms is investigated to achieve more reliable site-representative time histories.

Next, to produce seismic site factors and generate acceleration design response spectra curves (ADRS) for the seismic design of infrastructure systems, a framework-based GUI computer program, CarolinaADRS, is developed. This program includes the capability to import site-specific stratigraphic information to compute soil dynamic properties and seismic parameters for the analysis. Then, the capability to use current site factor models coupled with subsurface investigation and seismic hazard data is developed to calculate site factors and produce ADRS curves for a given location and hazard level in South Carolina.

Furthermore, the seismic hazard results from the CarolinaShake are used to investigate the effect of mild ground slope in site response analysis for the Charleston area. After the analysis, a set of slope adjustment factor charts is developed to adjust the seismic site factor results for the horizontal ground condition based on the site-specific shear wave velocity in the top 30 m and ground inclination at six spectral periods.

Finally, the finite element modeling of the Charleston seismic source is performed to generate the ground motions at the top of various geological sediments and ground surface in order to propose a detailed methodology to create a ground motion database at local and regional scales. Also, the results of the ground motions from the fault rupture propagation methodology are compared with those obtained from the CarolinaShake, one-dimensional site response analysis and synthetic seismograms to investigate their applicability.

Author ORCID Identifier

https://orcid.org/0000-0002-4976-3119

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