University of Southern California
department name USC Viterbi School of Engineering
 
about academics research faculty_staff news
 
admission students alumni
 
  Site Home > Prospective Students > Graduate Programs > PhD Programs > Earthquake Engineering        Calendar    |    Sitemap    |    Search
 
Why USC
Undergraduate Programs
Graduate Programs
PhD Programs
Research
How to apply
Brochures
Financial Aid
Masters Programs
Questions
Useful Links
   

  
 Earthquake Engineering  

Ph.D. Program in  Civil Engineering
Earthquake Engineering


 

Research in Earthquake Engineering at the University of Southern California focuses on the development of a basic understanding of all physical processes of earthquake generation, wave propagation and structural response. Measurements of strong ground motion and of structures are used to develop methods of predicting the characteristics of future earthquake shaking, soil-structure interaction and structural response.

 
Current Research
  • Performance Improvement of Long Period Building Structures subjected to Severe Pulse-Type Ground Motions (Anderson). Recent studies have shown that severe pulse-type ground motions may significantly increase the seismic response of long period structures. In extreme cases, this increased seismic demand, coupled with the action of gravity load, may pose a collapse hazard. The use of the traditional strategy of increasing the members' strength and/or stiffness alone may lead to inadequate and inefficient means of mitigating the problems. The use of innovative procedures for improving the performance of these structural systems is being investigated. Current attention is being focused on the use of supplemental (passive) damping in a mixed flexible-stiff structural system.
  • Repair and/or Retrofit of Welded Moment Connections (Anderson and Xiao). The most significant issue to arise from the Northridge Earthquake (1994) was the detection of cracking in welded beam to column connections of modern steel buildings. Shortly after the earthquake, connection specimens taken from a severely damaged building were delivered to USC for further testing under controlled laboratory conditions to evaluate the remaining strength and techniques for repair. A follow up program evaluated various repair procedures and a third program focused on the use of weld overlays for repair. Additional testing is being conducted as a service to local industry.
  • Development and Implementation of Improved Seismic Design and Retrofit Procedures for Bridge Abutments (Martin and Bardet). This research aims at (a) improving bridge seismic design procedures through better characterization of abutment load capacity, stiffness and damping characteristics, and (b) developing improved simplified seismic design and retrofit procedures for bridge abutments. The research will encompass parametric dynamic response analyses utilizing simplified bridge models coupled with finite element abutment models (LINOS, a finite element program for geomechanics and geotechnical engineering) and validation studies utilizing case histories.
  • Creation of Electronic Bulletin Board System for the Northridge Earthquake (Bardet). The objective of the research is to develop new electronic means of communication in Geotechnical Earthquake Engineering which enhance the collection and exchanges of strong motion and geotechnical data after the 1994 Northridge Earthquake. The new means of communication include two mailing lists (Usgeotech and Geotech) for posting messages of national and international interest, and a World Wide Web (WWW) site for storing and exchanging data under various formats. These new means of communication are part of the geotechnical branch of the Southern California Earthquake Center (SCEC).
  • Analysis of Ground Displacement and Failure in the Van Norman Facilities after the 1994 Northridge Earthquake (Bardet). The University of Southern California (USC) coordinates the research on the ground deformation and failure in the Van Norman Complex after the 1994 Northridge Earthquake. This research regroups USC, Case Western Reserve University, Dames & Moore, Cornell University, and the Los Angeles Department of Water and Power. The objective of this collaborative research is to analyze the strong-motion recordings in the Van Norman Complex, to measure the permanent ground displacements of the general area and of the Los Angeles Reservoir and Upper and Lower San Fernando Dams, by aerial and land surveys, to determine the material properties of hydraulic fills, and to investigate the validity of methods for nonlinear dynamic analysis based on well-documented field cases.
  • A Theoretical and Experimental Evaluation of the Vibroreplacement Ground Remediation Technique (Martin). This research aims at evaluating the potential magnitude and conditions leading to increased liquefaction resistance arising from (a) radial dissipation of earthquake induced pore-pressures to stone columns, (b) the effects of increased lateral effective stresses induced by stone column construction, and (c) the effects of increased ground stiffness due to stone columns.
  • Deformations near Underground Infrastructure (V.W. Lee). Los Angeles began the construction of the L.A. subway system in the early 1990's. Such construction, in recent years, has experienced some difficulties. It is important that we understand the causes of this structural damage. The County of Los Angeles is in a seismic region. We need to study the structural deformations resulting from the strong earthquake ground motions in the vicinity of the Los Angeles subway. The research started with the analysis of the deformations of surface canyons above an underground tunnel. This involved the consideration of diffraction of seismic waves in the presence of both surface and subsurface topographies. It resulted in much larger than expected (as much as three times) amplifications of surface displacements. The same methodology has also been applied to a practical problem from the 1994 Northridge earthquake. Case studies were based on large flexible corrugated metal pipes (CMP) which were shaken and damaged during the quake in the vicinity of the Van Norman Complex, in the San Fernando Valley.
  • A Study of Nonlinear Soil-Pile-Structure Interaction in Soft Soils during Strong Earthquakes (Martin and Bardet). This research aims at developing improved design methods for determining the influence of building-pile foundation interaction on the seismic response of tall building structures. The objectives will be accomplished by the integration of nonlinear discrete element and finite element models (LINOS), parametric dynamic response analyses and case history evaluations.
  • Characteristics of Earthquake Response Spectra in Southern California (Lee, Trifunac, Todorovska). The purpose of this research is to develop improved empirical equations for estimation of smooth elastic response spectra, for use in seismic design in Southern California. The emphasis is placed on developing and justifying the spectral shapes which relate to the physical characteristics of the source (near field, far field), attenuation, and local site (geological and soil) effects.
  • The FEMA-USC Hospital Project (Masri). In the 1994 Northridge Earthquake, 68 hospitals in the region had their normal operations disrupted by nonstructural damage. This experience provided further evidence that the functioning of a hospital during the critical hours following an earthquake depends largely on control of damage to nonstructural elements, equipment, and contents. Recent passage and enforcement of SB1953, which requires seismic upgrading of hospitals and critical care facilities, has a major focus on nonstructural damage control. In 1997, FEMA funded a major multi-year study entitled “Development, Evaluation, and Implementation of Standards for Seismic Mitigation Measures for Nonstructural Components in Hospitals and Critical Care Facilities.” Centered at the University of Southern California, this study is a collaboration of academic researchers, industry experts, and regulatory agencies. An integrated study plan combines the efforts of members of the USC Schools of Engineering, Medicine and Public Administration, the USC Institute of Safety and Systems Management, private engineering firms, and the California Office of Statewide Health Planning and Development (OSHPD). The team is evaluating the performance, assessing the impact on hospital functions and developing effective seismic mitigation measures for nonstructural elements, equipment, and contents. A systems” approach is followed, wherein the performance of hospital systems, not just individual components, is rigorously studied.
  • The Black Thunder Mine Liquefaction Experiment (Nigbor). Ground vibrations from very large (kiloton) mining blasts are used to simulate earthquake ground motions. In the first experiment, a large sand pit was artificially created at the mine site. A simple pile structure was installed and instrumented. Ground motions liquefied the saturated sand, allowing soil-pile interaction to be observed and measured. Analyses of extensive field data will provide insight into the liquefaction phenomenon and soil-pile interaction under liquefied conditions.
  • Resolution of Site Response Issues in the Northridge Earthquake (ROSRINE) (Nigbor, Bardet, and Swift). Important strong motion stations from the Northridge and other California earthquakes are being characterized through field investigations to assist in determining the contribution of site effects to measured ground shaking. Field investigations include drilling, geologic logging, geophysical logging, and SASW measurements. Samples obtained from the field are studied in the laboratory to determine index and dynamic properties. Data are then used in various analyses of the recorded ground shaking.
  • Earthquake Ground Motion from an Extended Seismic Source buried in a Viscoelastic Half-Space (M. Shinozuka). The main objective of the research is to study the physics of ground motion in the vicinity (near-field) of an extended earthquake fault buried in a layered viscoelastic half-space. The inhomogeneous rupture of the fault responsible for the generation of intermediate and high frequency waves will be described using the specific barrier model of Papageorgiou and Aki. This model has been successfully used in the past to interpret earthquake strong motion data. Also, the model has been used to provide an analytic description of far-field spectra of earthquake ground motion. However, there exist no analytic description of the spectral content of ground motion in the vicinity (near-field) of an extended earthquake fault.
  • Development of Computer Codes for Lifeline System Analysis (M. Shinozuka). Computer codes for lifeline system analysis are being developed. In particular, LIFELINE-W was developed on the basis of ARC/INFO for evaluating the seismic performance of water delivery systems. The code was specifically used to analyze the Memphis Light, Gas, and Water Divsion's water delivery system in Memphis, Tenn. The documentation of this code is under way. During documentation, improvements of the code will be made. For example, more realistic models for break patterns and leakage phenomena will be incorporated. LIFELINE-W will be modified to be able to perform gas and crude oil transmission system analysis.
  • Duration of Strong Motion Shaking in Southern California (Trifunac, Lee, Todorovska). New regression equations describing duration of strong ground motion in terms of seismic energy available to excite the structures are developed. The physical characterization of strong motion pulses, their amplitudes, number, frequency content, etc., are analyzed to describe the nature of the bursts of energy exciting the structures. Between the pulses, “quiet” portions of strong motion, and strong motion coda are investigated to provide continuity and understanding of the physical nature of strong motion, relative to the weaker coda waves in seismological studies. Two- and three-dimensional geometry of sedimentary basins (depth, width, length) relative to the station- source geometry is considered in describing the duration of strong motion.
  • Seismic Risk Assessment of USC Campus (Trifunac, Lee, Todorovska). Methods are developed for detailed seismic risk assessment of existing and future structures, and for the development of design criteria which optimize investment (in strengthening the existing structures and in design of new structures) and minimize future losses. Computation of direct and indirect losses is combined with a probabilistic description of future strong shaking and selection of optimal design strategies is facilitated via distribution functions of losses associated with chosen design scenarios.
  • Operation of the Los Angeles and Vicinity Strong Motion Network (Todorovska). Installed in 1979/80, this network was the first of its kind. It has 80 three- component accelerograph stations recording strong ground shaking throughout the metropolitan area in “free-field” conditions. This full scale urban laboratory has recorded so far about 1,500 three component accelerograms of many earthquakes and their aftershocks, including the 1987 Whittier-Narrows (M=5.9, 68 records), 1991 Sierra Madre (M=5.8, 65 records), 1992 Landers (M=7.5, 61 records) and 1994 Northridge (M=6.7, 65 records) earthquakes. These data have been invaluable for many engineering and seismological studies, of these earthquakes. They have added to the understanding and quantification of the spatial variation of strong ground shaking as functions of the propagation path, site geology and local soil conditions, the relationship between strong ground shaking and damage to structures, and the earthquake source mechanism.
  • Digitization and Processing of Data Recorded by the Los Angeles Strong Motion Network during the Northridge, California Earthquake of 17 January, 1994 (Todorovska). Strong earthquakes are rare events that occur unexpectedly, often on faults not previously mapped. Therefore, successful recording of mainshock ground shaking by dense arrays is very valuable, especially in densely populated urban areas. The Northridge Earthquake (ML=6.4, MW = 6.7) was recorded by 65 accelerographs of the Los Angeles Strong Motion Network, managed by USC. The processing involves high resolution digitization of the film records, filtering of noise, instrument correction, and computation of velocity and displacement time histories, and Fourier and Response Spectra. Techniques developed by USC faculty are used. Strong motion data is valuable for understanding the earthquake source, the nature of wave propagation in basins and strong ground shaking at a site, as well as of response and damage of engineered structures.
  • Seismic Response of Underground Structures (Wong). Development of new methodologies for analyzing the linear seismic response of underground structures which includes deeply embedded flexible storage tanks and retaining walls, horizontally lined tunnels and vertical shafts. Fully three-dimensional seismic waves are considered, even though two-dimensional models may be used for some extended structures.
  • Development of Prefabricated Composite Jacketing Systems for Seismic Retrofit of Bridge Columns (Xiao and Martin). In this multi-phase research program, several prefabricated composite jacketing systems for retrofitting bridge columns are experimentally evaluated and methods for analysis and retrofit design are developed. The first phase of the program involves testing of nine half scale model columns with 610 mm diameter circular sections to investigate the effectiveness of prefabricated composite jackets for flexure and shear retrofits. The second phase involves large scale testing and analysis of columns with rectangular sections. The third phase will be focused on the field implementation of the prefabricated jacketing systems for retrofitting actual bridges and long term monitoring.
  • Experimental and Analytical Studies of Structures and Structural Elements subjected to Variable Axial Loads (Xiao). Problems in analysis and design of structures and components subjected to variable axial loads are addressed in this project. Model columns are tested under cyclic lateral forces and variable axial loads to investigate the effect of axial load variation on seismic performance of columns. Analytical methods are developed and calibrated using the test results.
 
The Faculty
 
Selected Publications
  • Anderson, J.C., and Bertero, V.V. (1997). Seismic Response of a 42 Story Steel Building,” U.S. Geological Survey Professional Paper 1552-C, US Geological Survey Information Services, Denver, Colorado.
  • Anderson, J.C., and Maranian, P.J. (1998). Repair of Moment Connections using Weld Overlays,” Proceedings, Third U.S.-Japan Workshop on Steel Fracture Issues, Tokyo, April.
  • Anderson, J.C., and Johnston, R.G. (1998). Performance of a Steel Building which experienced Intense Ground Motion,” ASCE Journal of Performance of Constructed Facilities, 12(4).
  • Baratta, A., Elishakoff, L., Zuccaro, G., and Shinozuka, M. (1998). A Generalization of the Drenick-Shinozuka Model for Bounds on the Seismic Response of a Single Degree-of-Freedom System,” Earthquake Engineering and Structural Dynamics, 27, pp. 423-437.
  • Bardet, J.P., and Davis, C. (1996). Engineering Observations on Ground Motion at the Van Norman Complex after the 1994 Northridge Earthquake,” Bulletin of the Seismological Society of America, 86(1B), S333-S349.
  • Bardet, J.P., and Davis, C. (1996). Performance of San Fernando Dams during the 1994 Northridge Earthquake,” ASCE Journal of Geotechnical Engineering, 122(7), pp. 554-564.
  • Bardet, J. P., and Young, J. (1997). Grain Size Analysis by Buoyancy Method,” Geotechnical Testing Journal, ASTM, 20(4), pp. 481-486.
  • Bardet, J.P., and Davis, C.A. (1998). Deformation of Embankments from Liquefaction during the 1994 Northridge Earthquake,” Transportation Research Record 1633, Transportation Research Board.
  • Bardet, J.P., and Erten, D. (1999). Will it Happen Here?” ASCE Civil Engineering, 69(12), pp. 38-43.
  • Chang, S.E., and Shinozuka, M. (1996). Lifecycle Cost Analysis with Natural Hazard Risk,” ASCE Journal of Infrastructure Systems, 2(3), pp. 118-126.
  • Davis, C., and Bardet, J.P. (1996). Performance of Two Reservoirs during the 1994 Northridge Earthquake,” ASCE Journal of Geotechnical Engineering, 122(8), pp. 613-622.
  • Davis, C., and Bardet, J.P., (1998). Seismic Analysis of Large Diameter Flexible Underground Pipes,” ASCE Journal of Geotechnical and Geoenvironmental Engineering, 124(10), pp. 1005-1015
  • Davis, C.A. and Bardet, J.P. (2000). Case History and Analysis of Responses of Buried Corrugated Metal Pipes to Earthquakes,” ASCE Journal of Geotechnical and Geoenvironmental Engineering, 126(28), pp. 613-622.
  • Hwang, H.H.M., Lin, H., and Shinozuka, M. (1998). Seismic Performance Assessment of Water Delivery Systems,” Journal of Infrastructure Systems, 4(3), pp. 118-125.
  • Lee, V.W., Chen, S., and Hsu, I.R. (1999). Antiplane Tunnel,” ASCE Eng. Mech. Div., 125(6), pp. 668-675.
  • Lee, V.W., and Manoogian, M.E. (1995). Surface Motion above an Arbitrary Shape Underground Cavity of Incident SH Waves,” European Earthquake Engineering, 8(1), pp. 3-11.
  • Lee, V.W., Ghosh, T., and Sabban, M.S. (1995). Scattering and Diffraction of Plane P-Waves by 3-D Cylindrical Canals,” European Earthquake Engineering, IX(3), pp. 12-22.
  • Manoogian, M.E., and Lee, V.W. (1996). Diffraction of SH-Waves by Subsurface Inclusions of Arbitrary Shape,” ASCE Eng. Mech. Div., (2), pp. 123-129.
  • Martin, G.R., Lam, I., and Tsai, C.-F. (1980). Dissipation of Pore Pressures during Offshore Cyclic Loading,” ASCE Journal of Geotechnical Engineering, 106(9), pp. 981-995.
  • Masri, S.F., Smyth, A.W., Chassiakos, A.G. (1998). Detection of Structural Changes through Nonlinear System Identification Approaches,” Proc. Asia Pacific Workshop on Seismic Design and Retrofit of Structures, National Center for Research on Earthquake Engineering, Taipei, Taiwan, ROC, 10-13 August 1998.
  • Masri, S.F., and Smyth, A.W. (1999). A Compact Probabilistic Representation of Nonstationary Input Processes for MDOF Analytical Random Vibration Studies,” Proc. of Pan American Conference on Applied Mechanics (PACAM VI), 4-8 January, Rio de Janeiro, Brazil.
  • Morochnik, V., Bardet, J.P., and Hushmand, B. (1998). Identification of the Dynamic Properties of the OII Landfill,” ASCE Journal of Geotechnical and Geoenvironmental Engineering, 124(3), pp. 186-196.
  • Nakamura, M., Masri, S.F., Chassiakos, A.G.M., and Caughey, T.K. (1998). A Method for Nonparametric Damage Detection through the Use of Neural Networks,” Earthquake Engineering and Structural Dynamics, 27, pp. 997-1010.
  • Nigbor, R.L., Olsen, K.B., and Konno, T. (2000). 3D Viscoelastic Wave Propagation in the Upper Borrego Valley, California, constrained by Borehole and Surface Data,” BSSA, 90(1), pp. 134-150.
  • Shinozuka, M., and Yeigh, B. (1997). Uncertainty Modeling in Structural Stability,” Uncertainty Modeling in Finite Element, Fatigue and Stability of Structures (Series on Stability, Vibrations and Control Systems), 9, Chapter 7, pp. 215-260.
  • Shinozuka, M., Chang, S.E., Eguchi, R.T., Abrams, D.P., Hwang, H.M., and Rose, A. (1997). Advances in Earthquake Loss Estimation and Application to Memphis, Tennessee,” Earthquake Spectra, 13(4), pp. 739-758.
  • Shinozuka, M., Rose, A., and Eguchi, R.T. (1998). Engineering and Socioeconomic Impacts of Earthquake; an Analysis of Electricity of Lifetime Distributions in New Madrid Area,” Multidisciplinary Center for Earthquake Engineering Research, Monographic Series, No. 2, 1998.
  • Shinozuka, M., Zhang, R., Deodatis, G. (1998). Recent Developments in Engineering Applications of Near-Field Earthquake Motion Modeling,” Proceedings of First China-USA-Japan Workshop on Civil Infrastructure Systems, Shanghai, China, November 4-6.
  • Shinozuka, M. (1999). On-line Damage Identification of Water Delivery Systems,” 13th ASCE Engineering Mechanics Conference, Johns Hopkins University, Baltimore MD, USA, June 13-16.
  • Shinozuka, M., Deodatis, G., Zhang, R., Papgeorgiou, A.S. (1999). Modeling, Synthetics and Engineering Applications of Strong Earthquake Wave Motion,” Soil Dynamics and Earthquake Engineering, 18, pp. 209-228.
  • Todorovska, M.I., and Trifunac, M.D. (1996). Hazard Mapping of Normalized Peak Strain in Soil during Earthquakes: Microzonation of a Metropolitan Area,” Soil Dynamics and Earthquake Engineering, 15 (5), pp. 321-329.
  • Todorovska, M.I., and Trifunac, M.D. (1999). Liquefaction Opportunity Mapping via Seismic Wave Energy,” ASCE J. Geotechnical and Geoenvironmental Engrg., 125(12), pp. 1032-1042.
  • Todorovska, M.I. (1999). Base Isolation by a First Story with Inclined Columns,” ASCE J. of Engrg. Mech., 125(4), pp. 448-457.
  • Todorovska, M.I. (1998). Cross-Axis Sensitivity of Accelerographs with Pendulum Like Transducers: Mathematical Model and the Inverse Problem,” Earthquake Engrg. and Struct. Dynamics, 27, pp. 1031-1051.
  • Todorovska, M.I, Novikova, E.I., Trifunac, M.D., and Ivanovic, S.S. (1998). Advanced Sensitivity Calibration of the Los Angeles Strong Motion Array,” Earthquake Engrg. and Struct. Dynamics, 27, pp. 1053-1068.
  • Trifunac, M.D., and Todorovska, M.I. (1998). Non-Linear Soil Response as a Natural Passive Isolation Mechanism - the 1994 Northridge, California Earthquake,” Soil Dynamics and Earthquake Engrg., 17(1), pp. 41-51.
  • Wong, H.L., and Luco, J.E. (1991). Structural Control including Soil-Structure Interaction Effects,” ASCE Engineering Mechanics Division, 117(10), pp. 2237- 2250.
  • Xiao, Y., Priestley, M.J.N., and Seible, F. (1996). Seismic Assessment and Retrofit of Bridge Column Footings,” ACI Structural Journal, 93(l), pp. 79-94.
  • Zhang, R. and Shinozuka, M. (1996). Effects of Irregular Boundaries in Layered Half-Space on Seismic Waves,” Journal of Sound and Vibration, 195(1), pp. 1-16.