Structural response to near-field seismic motions

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Project Description

Long period structures like tall buildings, transmission towers and bridges are highly vulnerable to earthquake ground motions in seismic active regions. Collapse studies of many of these structures under damaging earthquakes have revealed the complex nature of near-field ground motions with pulse-like characteristics. The complexities in ground motions arise from the seismic source process, the intricacies of seismic wave propagation in a heterogeneous Earth structure, and the local geological/site conditions. To account for these complexities, earthquake engineers use empirical tools like Ground Motion Prediction Equations (GMPE’s) that make simplifying assumptions about the physics of the source, the medium properties, and the site conditions. These GMPEs are widely used to provide peak intensity measures of ground motion (e.g., Peak Ground Acceleration, PGA, Peak Ground Velocity, PGV, Peak Ground Displacement, PGD, Spectral Acceleration, SAT, at various building periods, T). While the peak amplitude parameters are the most commonly used intensity measures in earthquake engineering, estimated from these GMPEs, other measures exist that quantify the spectral and energy characteristics of earthquake ground motions. Often, the computed structural response of a given building is sensitive to these ground motion intensity measures, depending on the location and the characteristics of the structure. To derive an optimal measure of ground motion intensity, it is important to establish the correlations between structural response and the ground motion intensity measures. In this project, we plan to investigate seismic response of steel moment resisting frames. We model steel buildings with different stories, by providing eccentrically braced frames in the transverse direction for controlling the drift. We will compute the full seismic response in terms of story drifts and peak floor accelerations for a selected set of near-field ground motion records. The ground motions for our study will be obtained from the NGA-West2 database (Pacific Earthquake Engineering Research Center, PEER), covering a range of moment magnitudes Mw 4.0-9.0, Joyner-Boore distances Rjb <=150km and for Vs30 site classes A-E. We will compute some of the well-known ground motion intensity measures from the recorded dataset that represents the amplitude, spectral and energy characteristics of the ground motions. We will estimate correlations between the ground motion intensity measures and the engineering demand parameters (story drifts). The results from our study will provide useful insights for the choice of optimum inputs in performance-based design of structures.
Program - Earth Science and Engineering
Division - Physical Sciences and Engineering
Faculty Lab Link - https://ces.kaust.edu.sa/
Field of Study - Earthquake seismology / earthquake engineering

About the
Researcher

Paul Martin Mai

Professor, Earth Science and Engineering and Associate Dean (Students), Physical Science and Engineering Division

Paul Martin Mai
Research Interests
  • Multi-scale earthquake phenomena: from data-driven experimental studies to HPC-enabled forward simulations
  • Physics-based ground-motion simulations for seismic & tsunami hazard applications
  • Seismic waves in inhomogeneous media: scattering simulations and imaging Earth structure 
  • Engineering seismology, seismic hazard assessment, and coupled natural hazards (tsunamis, landslides)
  • Geothermal energy for Saudi Arabia: low-enthalpy geothermal energy system in Red Sea rift basins

Desired Project Deliverables

1- Selection of database for the near-field ground motion records 2- Estimation of ground motion intensity measures 3- Finite element modelling and analysis of the structures (using tools like Abaqus, SAP2000) 4- Establish correlations between seismic demand parameters and ground motion intensity measures 5- Documentation

RECOMMENDED STUDENT ACADEMIC & RESEARCH BACKGROUND

Degree in Earth Science Civil Engineering, or related fields
Degree in Earth Science Civil Engineering, or related fields
Experience in earthquake seismology , seismic waves, Fourier analysis, or structural engineering
Experience in earthquake seismology , seismic waves, Fourier analysis, or structural engineering