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Dam failure

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The document discusses the failure of the St. Francis Dam in 1928 near Los Angeles, California. It provides background on the dam's design and construction. On March 12, 1928, the dam catastrophically failed, releasing a flood wave that killed an estimated 450 people and destroyed over 1,000 homes and buildings. The failure was likely due to cracks and leaks that were dismissed by the dam's designer. The document recommends lessons for disaster management, including early warning systems and emergency preparedness.

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Bonab University Civil Engineering Department Bonab-Iran Dam failure Sajad Behnajad
The cause of failure may be classified as hydraulic failures (for all types of dams) failures due to seepage 1. through foundation (all except arch dams) 2. through body of dam (embankment dam) failures due to stresses developed within structure Arch dams fail instantaneously, whereas the gravity dams take some multiples of 10minutes
The percentage distribution of dam breaks and its attributes causes of failure Foundation problems 40 % Inadequate spillway 23 % Poor construction 12 % Uneven settlement 10 % High pore pressure 5 % Acts of war 3 % Embankment slips 2 % Defective materials 2 % Incorrect operations 2 % Earthquakes 1 %
Dam failures effects Dam failure results in a catastrophic break followed by a flood wave often with considerable loss of life or property More than a dozen dams have failed in South Carolina amid catastrophic flooding that has destroyed homes and businesses and left more than a dozen people dead The structures that have failed in South Carolina are like the vast majority of dams around the world: they are made of earth
Dam failures are most likely to happen for one of five reasons Overtopping Foundation Defects and Slope Instability Cracking Inadequate maintenance and upkeep Piping
Overtopping caused by water spilling over the top of a dam. Overtopping of a dam is often a precursor of dam failure. National statistics show that overtopping due to inadequate spillway design, debris blockage of spillways, or settlement of the dam crest account for approximately 34% of all U.S. dam failures
Foundation Defects and Slope Instability Foundation defects, including settlement and slope instability, cause about 30% of all dam failures
Piping It happens when seepage through a dam is not properly filtered and soil particles continue to progress and form sink holes in the dam 20% of U.S. dam failures have been caused by piping (internal erosion caused by seepage).
Failure Prevention Failure could have been prevented if some of these points had been observed Failure is a complex process Begins with some abnormality in behavior (not detected) Consequent deteriorations (not observed) Further damage or disaster Inspection and Monitoring of dams as well as data analysis and interpretation has a critical role in the field of dam safety
St. Francis Dam Disaster
Geography Located 40 miles NE of Los Angeles In city of Santa Clarita Developing city Agriculture, electricity (Edison), mostly immigrants Inside San Francisquito Canyon
Background Designed by William Mulholland, Dept. of Power and Water 1924 construction began Originally Capacity: 30,000 acre-feet 180 ft high, 600 ft long 1st change 10ft height increase Capacity: 32,000 acre-feet 2nd change (July 1925) 10ft height increase Capacity: 38,000 acre-feet Wing dyke added (600ft long) 1926 construction complete William Mulholland
Completed and filled reservoir St. Francis Dam construction http://www.scvhistory.com/scvhistory/scvhistory.htm
1926-1928 Cracks developing in dam and abutments Mulholland investigates and dismisses 7 March 1928 Reservoir fills to capacity More leaks develop Mulholland investigates and dismisses 12 March 1928 East side of reservoir roadbed sagging 1 5 feet More leaks and cracks Mulholland and assistant inspect and dismiss Evidence of leaks http://www.scvhistory.com/scvhistory/scvhistory.htm
12 March 1928 Dam fails 11:57 pm 12 bill gallons of water 18 mi/hr initially, 5 mi/hr into Pacific Traveled 55 miles to the Pacific Ocean Took 5 遜 hrs Dam after failure http://www.scvhistory.com/scvhistory/scvhistory.htm
Impacts Deaths: 450 estimated Many found downstream Tent residents of unknown count +900 homes destroyed 1,200 buildings damaged 10 bridges knocked out Power lost in multiple cities Crops, businesses and livestock affected
Overturned railroad tracks Debris and overturned cars http://www.scvhistory.com/scvhistory/scvhistory.htm
Disaster Management Awareness and preparedness No disaster plan No one ever thought it would break Mulholland was aware of cracks/leaks and maximum capacity Dismissed them because said, This is typical for a concrete dam of this size.
How was the community affected Many people lost jobs Edison electric power plants ruined Agriculture crops devastated Agriculture devastated 7,900 acres Citrus, walnuts, apricots, grapes, alfalfa, pecans Tent residents Lost jobs and displaced Rebuild homes and businesses Took very long for people to get back on their feet
Recommendations Warning system needed You can never be too careful, the risk of failure will always be there no matter the confidence More response by police force Efficiency needed with system of communication Reservoir shouldnt have been built there The geography is extremely dangerous
Sources http://www.scvhistory.com/scvhistory/scvhistory.htm http://en.wikipedia.org/wiki/San_Francisquito_Canyon http://web.umr.edu/~rogersda/st_francis_dam/lessons_learned _from_the_st_francis_dam_failure(geostrata_mar-apr_2006).pdf http://web.umr.edu/~rogersda/st_francis_dam/reassessment_o f_st_francis_dam_failure.pdf http://web.umr.edu/~rogersda/st_francis_dam/Mapping%20th e%20St%20Francis%20Dam%20Outburst%20Flood%20with%2 0GIS.pdf Sharif University Presentation based on dam failure Outland, Charles F. Man Made Disaster: the story of St. Francis Dam. Glendale, California: The Arthur H. Clark Company, 1963.
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Dam failure

  • 1. Bonab University Civil Engineering Department Bonab-Iran Dam failure Sajad Behnajad
  • 2. The cause of failure may be classified as hydraulic failures (for all types of dams) failures due to seepage 1. through foundation (all except arch dams) 2. through body of dam (embankment dam) failures due to stresses developed within structure Arch dams fail instantaneously, whereas the gravity dams take some multiples of 10minutes
  • 3. The percentage distribution of dam breaks and its attributes causes of failure Foundation problems 40 % Inadequate spillway 23 % Poor construction 12 % Uneven settlement 10 % High pore pressure 5 % Acts of war 3 % Embankment slips 2 % Defective materials 2 % Incorrect operations 2 % Earthquakes 1 %
  • 4. Dam failures effects Dam failure results in a catastrophic break followed by a flood wave often with considerable loss of life or property More than a dozen dams have failed in South Carolina amid catastrophic flooding that has destroyed homes and businesses and left more than a dozen people dead The structures that have failed in South Carolina are like the vast majority of dams around the world: they are made of earth
  • 5. Dam failures are most likely to happen for one of five reasons Overtopping Foundation Defects and Slope Instability Cracking Inadequate maintenance and upkeep Piping
  • 6. Overtopping caused by water spilling over the top of a dam. Overtopping of a dam is often a precursor of dam failure. National statistics show that overtopping due to inadequate spillway design, debris blockage of spillways, or settlement of the dam crest account for approximately 34% of all U.S. dam failures
  • 7. Foundation Defects and Slope Instability Foundation defects, including settlement and slope instability, cause about 30% of all dam failures
  • 8. Piping It happens when seepage through a dam is not properly filtered and soil particles continue to progress and form sink holes in the dam 20% of U.S. dam failures have been caused by piping (internal erosion caused by seepage).
  • 9. Failure Prevention Failure could have been prevented if some of these points had been observed Failure is a complex process Begins with some abnormality in behavior (not detected) Consequent deteriorations (not observed) Further damage or disaster Inspection and Monitoring of dams as well as data analysis and interpretation has a critical role in the field of dam safety
  • 10. St. Francis Dam Disaster
  • 11. Geography Located 40 miles NE of Los Angeles In city of Santa Clarita Developing city Agriculture, electricity (Edison), mostly immigrants Inside San Francisquito Canyon
  • 12. Background Designed by William Mulholland, Dept. of Power and Water 1924 construction began Originally Capacity: 30,000 acre-feet 180 ft high, 600 ft long 1st change 10ft height increase Capacity: 32,000 acre-feet 2nd change (July 1925) 10ft height increase Capacity: 38,000 acre-feet Wing dyke added (600ft long) 1926 construction complete William Mulholland
  • 13. Completed and filled reservoir St. Francis Dam construction http://www.scvhistory.com/scvhistory/scvhistory.htm
  • 14. 1926-1928 Cracks developing in dam and abutments Mulholland investigates and dismisses 7 March 1928 Reservoir fills to capacity More leaks develop Mulholland investigates and dismisses 12 March 1928 East side of reservoir roadbed sagging 1 5 feet More leaks and cracks Mulholland and assistant inspect and dismiss Evidence of leaks http://www.scvhistory.com/scvhistory/scvhistory.htm
  • 15. 12 March 1928 Dam fails 11:57 pm 12 bill gallons of water 18 mi/hr initially, 5 mi/hr into Pacific Traveled 55 miles to the Pacific Ocean Took 5 遜 hrs Dam after failure http://www.scvhistory.com/scvhistory/scvhistory.htm
  • 16. Impacts Deaths: 450 estimated Many found downstream Tent residents of unknown count +900 homes destroyed 1,200 buildings damaged 10 bridges knocked out Power lost in multiple cities Crops, businesses and livestock affected
  • 17. Overturned railroad tracks Debris and overturned cars http://www.scvhistory.com/scvhistory/scvhistory.htm
  • 18. Disaster Management Awareness and preparedness No disaster plan No one ever thought it would break Mulholland was aware of cracks/leaks and maximum capacity Dismissed them because said, This is typical for a concrete dam of this size.
  • 19. How was the community affected Many people lost jobs Edison electric power plants ruined Agriculture crops devastated Agriculture devastated 7,900 acres Citrus, walnuts, apricots, grapes, alfalfa, pecans Tent residents Lost jobs and displaced Rebuild homes and businesses Took very long for people to get back on their feet
  • 20. Recommendations Warning system needed You can never be too careful, the risk of failure will always be there no matter the confidence More response by police force Efficiency needed with system of communication Reservoir shouldnt have been built there The geography is extremely dangerous
  • 21. Sources http://www.scvhistory.com/scvhistory/scvhistory.htm http://en.wikipedia.org/wiki/San_Francisquito_Canyon http://web.umr.edu/~rogersda/st_francis_dam/lessons_learned _from_the_st_francis_dam_failure(geostrata_mar-apr_2006).pdf http://web.umr.edu/~rogersda/st_francis_dam/reassessment_o f_st_francis_dam_failure.pdf http://web.umr.edu/~rogersda/st_francis_dam/Mapping%20th e%20St%20Francis%20Dam%20Outburst%20Flood%20with%2 0GIS.pdf Sharif University Presentation based on dam failure Outland, Charles F. Man Made Disaster: the story of St. Francis Dam. Glendale, California: The Arthur H. Clark Company, 1963.