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This webinar was co-sponsored by ASCE's Geotechnical Institute (G-I) and ASCE Continuing Education
Instructor: Jean-Louis Briaud, Ph.D., P.E., BC.GE, Dist.M.ASCE
Course Length: 90 minutes
Purpose and Background
Bridge scour is the number one cause of bridge collapse in the US, yet the existing guidelines are felt to be excessively conservative. These apparently conflicting statements are due to the fact that most bridge foundations designed before 1987 did not consider scour as part of the design. The Observation Method for Scour (OMS) was developed to address the conservatism inherent in the current procedures by relying significantly on past observations at the bridge. This webinar presents the four steps that OMS utilizes. It presents 11 bridge scour case histories in Texas and in Massachusetts where the OMS was applied and uses the results to compare predicted and measured values of Zfut for both the OMS and the current FHWA guidelines. It also outlines the advantages and drawbacks of the OMS in a final section.
Primary Discussion Topics
- Bridge scour depth calculations
- Current design guidelines
- New method: observation method for scour or OMS
- Comparison against case histories and measured data
- Advantages and drawbacks
Learning Outcomes
Upon completion of this course, you will be able to:
- Perform scour depth calculations according to a new method
- Determine how OMS works
- Discuss the advantages and disadvantages of OMS
Webinar Benefits
- Review of basic soil erosion principles, erosion testing, existing charts for obtaining critical velocity of soils, and erosion categories for soils and rocks
- Learn to use a scour depth calculation method which is based upon various factors
- Discuss various bridge scour case histories
Assessment of Learning Outcomes
Students' achievement of the learning outcomes will be assessed via a short post-assessment (true-false, multiple choice and fill in the blank questions).
Intended Audience
- Hydraulic engineers (EWRI members)
- Geotechnical engineers (GI members)
- Structural engineers (SEI members)
- Department of Transportation engineers dealing with bridges
- USBR
- USACE
Webinar Outline
- Review of soil erosion principles
- Review of soil erosion testing
- Review of erosion classification and critical velocity values
- Step 1 of the OMS: collecting the maximum observed scour depth at the bridge, Zmo.
- Step 2 of the OMS: finding out what is the biggest flood velocity Vmo that the bridge has been subjected to since its construction
- Step 3 of the OMS: what will be the scour depth Zfut if the bridge is subjected to a major flood velocity Vfut
- Step 4 of the OMS: comparison between Zfut and the allowable scour depth Zall for the foundation
- Case histories for 11 bridge scour case histories in Texas and in Massachusetts
- Comparison between OMS predictions, FHWA guidelines predictions, and measured scour depth
- Advantages and drawbacks of the OMS
- TAMU-OMS spread sheet for automated calculations
How to Earn your CEUs/PDHs and Receive Your Certificate of Completion
To receive your certificate of completion, you will need to complete a short on-line post-test and receive a passing score of 70% or higher within 1 year of purchasing the course.
How do I convert CEUs to PDHs?
1.0 CEU = 10 PDHs [Example: 0.1 CEU = 1 PDH]