Crack In Wanapum Dam Blamed On Math Error - NBC Right Now/KNDO/KNDU Tri-Cities, Yakima, WA |

Crack In Wanapum Dam Blamed On Math Error

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The fracture forming on spillway monolith No. 4 may have been exacerbated by a weak construction joint. The fracture forming on spillway monolith No. 4 may have been exacerbated by a weak construction joint.
A team of engineers discovered the mathematical error while examining the original design calculations of the Wanapum Dam spillway. A team of engineers discovered the mathematical error while examining the original design calculations of the Wanapum Dam spillway.
BEVERLY, Wash. - After an 11-week investigation by the Grant County PUD, officials have determined that a math error in pre-construction was the main reason a crack developed in the Wanapum Dam. 

The results of the investigation still have to be reviewed by the Grant County PUD's Board of Consultant, but so far it appears a crack formed on a spillway may have been made worse by a weak construction joint. 

Engineers recalculated the original designs of the dam and found that additional concrete and/or reinforced steel should have been included when the dam was built 50 years ago. Officials say the original designers of the dam miscalculated that the spillway's concrete provided enough strength to resist the force of the water pushing against it. 

Repairs will be made to the dam throughout the summer, meaning water levels will be low for most of the season. 

Grant County PUD provided a diagram of how the crack formed over time. You can view the diagram by clicking the photo attached to this story. 
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