FLOOD04125

• County: Statewide
• Basin: Statewide
• Title: Interim Procedures for Evaluating Scour at Bridges
• Date: 9/1/1988
• Prepared By: Federal Highway Administration
• Floodplain - Doc Type: Educational/Technical/Reference Information

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For purposes of evaluating the substructure under Item 60 resistance to scour,
the questions remain essentially the same for foundations in deep water as for
foundations in shallow water:

o what does the stream cross-section look. like at the bridge;

o have there been any changes as compared to previous cross-section
measurements. If so does this include that (I) stream is aggrading or
degrading; or (2) that local or contraction scour is occurring around
piers and abutments;

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o what is the shape and depths of scour holes;

o is the foundation footing (or the piling) exposed to the stream flow,
and if so what is the extent and probable consequences of this
condition?

E. NOTIFICATION PROCEDURES

The bridge inspector's site evaluation of the effect of water at the bridge is
an important part of a bridge inspection. He must have a positive means of
promptly communicating his findings to the proper agency personnel. Any
condition that the bridge inspector considers to be of an emergency or
potentially hazardous nature should be reported i...diately. Other conditions
which do not pose an i..ediate hazard may still warrant further action and
should be conveyed to the hydraulics/foundation engineers for their review.

Most states have a procedure enabling the inspector to report maintenance
needs. This form, in most instances, can readily be adopted just by routing a
copy to the proper agency section. If a form of reporting procedure is not
available, one should be developed to assure that the hydraulic/foundation
engineer is informed of existing or potential problems and can take action to
further evaluate the bridge.

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