Earthquake Induced Ground Motions

Instructor

Dr. Praveen K. Malhotra
Dr. Praveen Malhotra is a Senior Research Scientist with FM Global Research in Norwood, MA. He has over 15 years of research, practical, and teaching experience in various aspects of earthquake engineering. For the last 5 years, his research has been focused on the loss prevention and loss estimation aspects of earthquake ground shaking. For 7 years prior to that, he measured and analyzed seismic records from structures and ground stations throughout California.

He has taught graduate, undergraduate, and continuing education courses in earthquake engineering, soil, and structural dynamics. He has more than 25 papers published in peer-reviewed journals and has made invited presentations throughout USA, South Korea, Switzerland, and India. He has been a member of teams sent out to collect scientific data following earthquakes. Dr. Malhotra has a Ph.D. in structural engineering, with emphasis on earthquake engineering, from Rice University. He is a member of the American Society of Civil Engineers (ASCE), Earthquake Engineering Research Institute (EERI), Seismological Society of America (SSA), and the Indian Society of Earthquake Technology (ISET). He serves on national committees dealing with seismic issues. He peer-reviews research articles submitted to various journals, and research proposals submitted for funding to various agencies. He is a registered Civil Engineer (P.E.) in California.

Course Description

This seminar presents a step-by-step evaluation of ground motions for design and assessment of structures for seismic loads. The evaluation of site-specific ground motions requires an interaction between geology, seismology, geotechnical engineering, and structural engineering. Professionals in any of these fields possess some knowledge of the related fields, but, invariably gaps are left in this knowledge. This seminar is aimed at closing those gaps through an intuitive approach. The seminar is divided into 6 parts, each aimed at answering a few key questions:

1. Basic geology and seismology: Why earthquakes happen? Where will future earthquakes occur? What will be the size and frequency of future earthquakes?
2. Ground motions from past earthquakes: How the ground motions are measured? Which characteristics of ground motions are most significant for engineering analyses? What are the key parameters to capture these characteristics?
3. Ground motions for future earthquakes: How are the ground motion prediction relationships derived from the prerecorded seismic data? How are these relationships used to estimate ground motions for future earthquakes? How are the ground motion hazard maps in building codes generated?
4. Effect of local geology on ground motions: How do the local soil conditions affect the ground motions at a site? How are these effects quantified?
5. Near-source effects on ground motions: What are the special characteristics of ground motions in close proximity of major seismic sources? How do they affect the response of structures?
6. Soil-structure interaction: How does the presence of a structure influence the ground motion at a site?

Seminar Benefits

• Learn about the ground motion characteristics  which influence the dynamic response of structures
• Learn to perform site-specific seismic hazard calculations using deterministic and probabilistic analyses
• Learn how to select and modify ground motion histories for dynamic analyses
• Obtain information on the sources of ground motion data
• Gain insight into the effects of local soil conditions on ground motion characteristics
• Learn background information regarding the ground motion provisions in UBC, NEHRP, ASCE7, IBC and NFPA 5000
• Learn the difference between hazard and risk

Who Should Attend

Structural engineers, geotechnical engineers, geologists, architects, building officials, and professionals in related fields who are interested in consolidating and widening their knowledge of earthquake ground motions, and their effects on structures and soil deposits.

Summary Outline

Day One (8:30 am - 5:30 pm)

• Basic Geology and Seismology
  • Plate tectonics
  • Seismic sources
  • Seismic waves
  • Earthquake magnitude scales
  • Earthquake potential of a source
  • Frequency of earthquakes on a source
• Ground Motion Histories
  • Amplitude, duration, and frequency parameters of ground motions
  • Sources of strong-motion data
• Seismic Response Spectrum
  • Dynamic response characteristics of structures
  • Calculation of response spectrum from ground motion      histories
  • Calculation of response spectrum from ground motion      parameters
  • Pseudo-acceleration, pseudo-velocity, and deformation      response spectra
  • Tripartite response spectrum
  • Smooth response spectrum
  • Acceleration-deformation spectrum for push-over analysis
• Ground Motion Prediction Relationships
  • Prediction relations for spectral accelerations and duration
  • Effects of geology on ground motion attenuation

Day Two (8:00 am - 5:00 pm)

• Site-Specific Response Spectrum and Duration
  • Deterministic seismic hazard analysis
  • Probabilistic seismic hazard analysis
  • Uniform hazard response spectrum
  • De-aggregation of hazard
  • Seismic hazard maps in building codes
  • Seismic hazard versus risk
• Site-Specific Ground Motion Histories
  • Selection and modification of recorded histories
  • Generation of synthetic histories
• Effects of Local Geology on Ground Motions
  • Dynamic characteristics of soil deposits
  • SHAKE analysis
  • Effects of: (1) soil stiffness and damping, (2) bedrock stiffness, and (3) intensity of shaking, on free-surface ground motions
  • Simple code-type procedure for considering soil effects
• Near-Fault Effects on Ground Motions and Response Spectra
  • Directivity and 'fling' effects
• Soil-Structure Interaction
  • Kinematic and inertial interaction