Attachment "A" Descriptions

Additional Guidance for Assessment of Bridges Over Waterways with Unknown Foundations

Box 1 - Step 1 - Perform initial screening and assessment to group and categorize bridges for action based on risk of failure and impact to user.
Box 2 - Step 2 - Define thresholds for potential risk categories (example A - High, B - Moderate, C- Low)
Define tolerable criteria for each category (e.g. For A - Positive Discovery, B- Inference, C - Risk acceptable for categorical POA or remedial countermeasures).
Box 3 - Step 3 - Go to Category A Flowchart
Box 4 - Step 4 - Go to Category B Flowchart
Box 5 - Step 5 - Go to Category C Flowchart

Box 1 - Perform refined quantitative risk assessment and further prioritize bridges. An example method is detailed in NCHRP Web Only Document 107.
Go to Box 2 - Collect available bridge data (e.g.) - Bridge Inspection Reports, Scour Evaluation Reports, Plans, Pile Driving Records, Other
Go to Decision Box 3 - Are the as-built foundation dimensions shown in the data collected?
If Decision Box 3 is no, got to Box 4 - Investigate and Evaluate Foundation Depth of Embedment (Positive Discovery)
Go to Decision Box 5 - Can scour evaluation be completed?
If Decision Box 5 is no, go to Box 6 - Develop and Implement a Plan of Action for the U coded bridge (see commentary)
If Decision Box 5 is yes, go to Box 7 - Conduct scour evaluation and recode bridge in Item 113
If Decision Box 3 is yes, go to Decision Box 8 - Does the available data contain Scour design information?
If Decision Box 8 is no, go to Box 9 - Then, use the foundation dimensions to complete the Scour Evaluation and recode in Item 113
If Decision Box 8 is yes, go to Box 10 - Check scour evaluation and recode Item 113

Box 1 - Perform refined quantitative risk assessment and further prioritize bridges.
Decision Box 2 - Are the as-built foundation dimensions shown in the data collected?
If Decision Box 2 is no, go to Box 3 - Assume foundation characteristics using inference methods.
Go to Decision Box 4 - Are the inferred foundation dimensions adequate to assess scour
If Decision Box 4 is yes, go to Box 5 - Conduct scour evaluation and recode bridge in Item 113.
If Decision Box 4 is no, go to Decision Box 6 - Is foundation discovery necessary based on risk assessment?
If Decision Box 6 is no, go to Box 7 - Develop and implement Plan of Action for the U coded bridge.
If Decision Box 6 is yes, go to Box 8 - Investigate and evaluate Foundation Depth (Positive Discovery)
Go to Decision Box 9 - Can scour evaluation be completed?
If Decision Box 9 is no, go to Box 7 above
If Decision Box 9 is yes, go to Box 10 - Use the foundation dimensions to complete the scour evaluation and recode bridge in Item 113.
If Decision Box 2 is yes, go to Decision Box 11 - Does the available data contain scour design information?
If Decision Box 11 is no, go to Box 12 - Use the foundation dimensions to complete the scour evaluation and recode bridge in Item 113.
If Decision Box 11 is yes, go to Box 13 - Recode Item 113 for the bridge.

Box 1 - Perform refined quantitative risk assessment and further prioritize bridges.
Go to Decision Box 2 - Are the as-built foundation dimensions shown in the data collected?
If Decision Box 2 is no, go to Box 3 - Assume foundation characteristics using inference methods.
Go to Decision Box 4 - Are the inferred foundation dimensions adequate to assess scour vulnerability?
If Decision Box 4 is yes, go to Box 5 - Conduct scour evaluation and recode bridge in Item 113
If Decision Box 4 is no, go to Box 6 - Develop and implement a Plan of Action for the U coded bridge
If Decision Box 2 is yes, go to Decision Box 7 - Does the available data contain scour design information?
If Decision Box 7 is no, go to Box 8 - Use the foundation dimension to complete the scour evaluation and recode bridge in Item 113.
If Decision Box 7 is yes, go to Box 9 - Recode Item 113 for the bridge.