Project Number:
03-27
Research Project:
Methodology for Probabilistic Assessment of Permanent Ground Displacement Across Earthquake Faults for the Transportation System
P.I. Name & Address:
Maria I. Todorovska
University of Southern California
Civil & Environmental Engineering Department
Los Angeles, CA90089-2531
Tel:(213) 740-0616
Fax:(213) 744-1426
Email: kgrote@csulb.edu
Project Objective:
The objective of the proposed one-year effort is to: (1) develop a methodology for probabilistic assessment of the permanent ground displacement across faults caused by earthquakes, and (2) demonstrate the methodology on an example fault in the Los Angeles area.This methodology is relevant for (a) deign and retrofit of bridges and tunnel structures that cross earthquake faults, (b) seismic risk assessment for the ground transportation system, i.e. the risk for physical damage, loss of function, and overall economic consequences on the regional economy, and (3) emergency planning. There are many examples of such structures, already built or under construction, and there will be more of these in the future.Actual damage of bridges crossing a fault has been observed in Turkey from the 1999 Duzce earthquake (M = 7.2) and in Taiwan from the 1999 earthquake (M = 7.6).
Permanent differential displacements can be caused also by lateral spreading associated with soil liquefaction, and by landslides.A natural continuation of the proposed project will be to extend it to include such events. Funding for this will be requested from METRANS upon the completion of the proposed project.It is believed that the proposed project will generate future funding from Caltrans on application of these methodologies to actual bridge and tunnel sites.Caltrans engineers consider the proposed methodology to be a valuable tool for specification of the design loads of bridges and tunnels.A letter of endorsement is enclosed, from Mr. Anoosh Shamshabadi a structural engineer of the Caltrans Office of Earthquake Engineering, who agreed to participate in the proposed project.
The proposed methodology will be developed within the framework of probabilistic seismic hazard analysis, which considers all conceivable earthquakes that may affect the structure of interest, as well as their likelihood of occurrence during the life or service time of the structure.Hence, it will be consistent with the description of ground motion related to the dynamic loads in structures caused by earthquake shaking.It will also make it possible to compare the seismic risk with the risks associated with other natural or man made hazards.
Both Principal Investigators have expertise in the areas of earthquake engineering and engineering seismology, and in particular in seismic source mechanism and in probabilistic seismic hazard analysis, which is required to successfully complete the proposed work.The proposed methodology is an extension of their previous work on seismic hazard assessment.
Task Descriptions:
1. Gather and review published data on fault slip from past earthquakes (2 months)
2. Develop a regression model for the average fault slip (over the fault surface) as function of magnitude, for different types of faulting (strike-slip, thrust, reverse, and combined faulting) (1 month)
3. Using theoretical models of earthquake faulting, describe the displacement on the ground surface for given average fault slip, earthquake magnitude and hypocentral depth (2 months)
4. Write a module for the computer program NEQRISK (Anderson and Trifunac, 1977; Lee and Trifunac, 1985) that would calculate the conditional probability that given permanent displacement on the ground surface will not be exceeded from an earthquake during a specified exposure time period (1 month)
5. Write a module for the computer program NEQRISK that would calculate the hazard that a) given level of fault displacement on the surface will not be exceeded from any single earthquake during a specified exposure period, and b) the cumulative displacement on the ground surface from all earthquakes during the exposure period will not exceed a specified level. (2 months)
6. Demonstrate the methodology by applying it to a hypothetic fault with characteristics similar to those of the Newport-Englewood fault in metropolitan Los Angeles.Study the sensitivity of the results on the input (2 months)
7. Write a final report, and journal and conference papers (2 months)
Milestones, Dates:
January 1, 2003 - December 31, 2004
Total Budget:
$80,000
Student Involvement:
One Student @ 50% time 12 months
Relationship to Other Research Projects:
Related to 03-17
Technology Transfer Activities:
Project report posted on the website
Potential Benefits of the Project:
Bridge design and retrofit to reduce rish of seismic damage
TRB Keywords:
Earthquake risk, seismic hazard analysis
Primary Subject:
Maintenance and operations of physical infrastructure
Goals:
Safety
Enabling Research:
Sensing and measurement
Modal Orientation:
Highway, transit
