Observation Method for Estimating Future Scour Depth at Existing Bridges
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 139, Issue 7
Abstract
Bridge scour can cause damage to bridge foundations and abutments. Bridges with foundations that are unstable for calculated and/or observed scour conditions are termed scour-critical bridges. There are approximately 17,000 scour-critical bridges in the United States. This designation comes in part from the use of overly conservative methods that predict excessive scour depths in erosion-resistant materials. Other methods capable of overcoming this overconservatism are relatively uneconomical because they require site-specific erosion testing. This paper proposes a new bridge scour assessment method. The new method, termed the observation method for scour (OMS), was developed for the Texas Department of Transportation’s statewide bridge scour assessment program. The proposed method does not require site-specific erosion testing and accounts for time-dependent scour in erosion-resistant materials. OMS was developed for use as a first-order assessment in combination with a routine bridge inspection program. OMS uses charts that extrapolate or interpolate measured scour depths at the bridge to obtain the scour depth corresponding to a specified future flood event. The scour vulnerability depends on the comparison between the predicted and allowable scour depths. This paper also includes a new hydraulic-hydrologic analysis procedure for the determination of flow parameters required in OMS. This procedure was developed specifically for the state of Texas. The new hydraulic-hydrologic analysis procedure could possibly be applied to other regions that have sufficient flow gauges. The nine case histories used to validate OMS showed good agreement between predicted and measured values. OMS was then applied to 16 bridges, 10 of which were scour-critical bridges that had sufficient information for OMS to be carried out. Six out of these 10 bridges were found to be stable according to OMS.
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Acknowledgments
This paper is an outcome of a bridge scour project funded by the Texas Department of Transportation (Grant No. 0-5505). The authors are grateful for this support. Ms. Laurie Couillard of Geocomp Corporation and Mr. John Hobbs of the Texas Transportation Institute helped with editing some of the figures. The authors are thankful for their assistance.
References
Briaud, J.-L. (2008). “Case histories in soil and rock erosion: Woodrow Wilson Bridge, Brazos River Meander, Normandy Cliffs, and New Orleans levees; 2007 Ralph B. Peck lecture.” J. Geotech. Geoenviron. Eng., 134(10), 1425–1447.
Briaud, J.-L., Chen, H.-C., Chang, K.-A., Oh, S. J., and Chen, X. (2009a). “Abutment scour in cohesive materials.” Rep. 24-15(2), National Cooperative Highway Research Program, Transportation Research Board, Washington, DC.
Briaud, J.-L., Chen, H.-C., Kwak, K. W., Han, S. W., and Ting, F. C. K. (2001b). “Multiflood and multilayer method for scour rate prediction at bridge piers.” J. Geotech. Geoenviron. Eng., 127(2), 114–125.
Briaud, J.-L., Chen, H.-C., Li, Y., Nurtjahyo, P., and Wang, J. (2003). “Complex pier scour and contraction scour in cohesive soils.” Rep. 24-15, National Cooperative Highway Research Program, Transportation Research Board, Washington, DC.
Briaud, J.-L., Chen, H.-C., Li, Y., Nurtjahyo, P., and Wang, J. (2005). “SRICOS-EFA method for contraction scour in cohesive soils.” J. Geotech. Geoenviron. Eng., 131(10), 1283–1294.
Briaud, J.-L., Govindasamy, A. V., Kim, D., Gardoni, P., Olivera, F., Chen, H., Mathewson, C. C., and Elsbury, K. (2009b). “Simplified method for estimating scour at bridges.” Rep. 0 5505-1, Texas Department of Transportation, Austin, TX.
Briaud, J.-L., Ting, F. C. K., Chen, H.-C., Cao, Y., Han, S. W., and Kwak, K. W. (2001a). “Erosion function apparatus for scour rate predictions.” J. Geotech. Geoenviron. Eng., 127(2), 105–113.
Briaud, J.-L., Ting, F. C. K., Chen, H.-C., Gudavalli, R., Perugu, S., and Wei, G. (1999). “SRICOS: Prediction of scour rate in cohesive soils at bridge piers.” J. Geotech. Geoenviron. Eng., 125(4), 237–246.
Govindasamy, A. V. (2009). “Simplified method for estimating future scour depth at existing bridges.” Ph.D. dissertation, Texas A&M Univ., College Station, TX.
Haeni, F. P., and Gorin, S. R. (1989). “Post-flood measurement of a refilled scour hole at the Bulkeley Bridge in Hartford, Connecticut.” Federal Highway Administration Rep. FHWA-RD-90-035, McLean, VA.
Holnbeck, S. R., and Parrett, C. (1997). “Method for rapid estimation of scour at highway bridges based on limited site data.” Water-Resources Investigations Rep. 96-4310, USGS, Denver, 79.
Hosking, J. R. M. (1990). “L-moments: Analysis and estimation of distributions using linear combinations of ordered statistics.” J.R. Statis. Soc. Ser., B52(1), 105–124.
Huizinga, R. J., and Rydlund, P. H. (2004). “Potential-scour assessments and estimates of scour depth using different techniques at selected bridge sites in Missouri.” Scientific Investigations Rep. 2004-5213, USGS and Missouri Department of Transportation, Reston, VA, 42.
Johnson, P. A. (2005). “Preliminary assessment and rating of stream channel stability near bridges.” J. Hydraul. Eng., 131(10), 845–852.
Lagasse, P. F., Schall, J. D., Johnson, F., Richardson, E. V., and Chang, F. (1995). “Stream stability at highway structures.” Federal Highway Administration Rep. FHWA-IP-90-014 (HEC 20), Washington, DC, 144.
Pagan-Ortiz, J. E. (1998). “Status of scour evaluation of bridges over waterways in the United States.” Proc., ASCE Conf. on Water Resource Engineering, ASCE, Reston, VA, 2–4.
Placzek, G., and Haeni, F. P. (1995). “Surface geophysical techniques used to detect existing and infilled scour holes near bridge piers.” Water-Resources Investigation Rep. 95-4009, USGS, Denver.
Richardson, E. V., and Davis, S. M. (2001). “Evaluating scour at bridges.” Rep. FHWA NHI 01-001 (HEC 18), United States Department of Transportation, Washington, DC.
Simon, A., Outlaw, G. S., and Thoman, R. (1989). “Evaluation, modeling and mapping of potential bridge scour, West Tennessee.” Proc., Bridge Scour Symp., Federal Highway Administration and USGS, Denver, 112–139.
United States Army Corps of Engineers (USCOE). (2010). “HEC-RAS river analysis system user's manual.” Version 4.1, Hydraulic Engineering Center, Davis, CA.
Wang, J. (2004). “The SRICOS-EFA method for complex pier and contraction scour.” Ph.D. thesis, Texas A&M Univ., College Station, TX.
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Published In
Journal of Geotechnical and Geoenvironmental Engineering
Volume 139 • Issue 7 • July 2013
Pages: 1165 - 1175
Copyright
© 2013 American Society of Civil Engineers.
History
Received: Dec 9, 2010
Accepted: Sep 14, 2012
Published online: Sep 18, 2012
Published in print: Jul 1, 2013
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