Every two years, County maintained bridges are inspected by a consulting engineering firm hired by Harford County. The structural components of the bridges, the stream channels, and the earth slopes are visually inspected and the conditions of each are recorded and photographed. Any repairs and/or replacements of structural components prior to the inspection are also recorded. Based on this information, the consulting engineering firm makes recommendations as necessary for bridge replacement, bridge rehabilitation, or bridge repairs. The consulting engineering firm collates this information into a Bridge Inspection Report for each bridge. The recommendations generated in the Bridge Inspection Reports are then used to develop the Bridge Replacement Program, the Bridge Rehabilitation Program, the Bridge Scour Program and routine bridge maintenance.

Photo by Mike Silva © 1998

Bridge Replacement Program

The Bridge Inspection Reports provide the initial data for determining which bridges need to be replaced. Harford County staff visits each potential bridge replacement site to verify existing bridge conditions and to establish a priority for replacing the bridge. The following are some factors used to evaluate the need and priority of a bridge for replacement:

Bridge Rehabilitation Program

Bridges that do not meet the criteria for full bridge replacement are repaired or maintained under the Bridge Rehabilitation Program. Rehabilitation work is done to extend the useful life of the bridge and to strengthen the existing bridge. The Bridge Rehabilitation Program provides preventative maintenance that addresses potential problems in lieu of full bridge replacement saving the County thousands of dollars. Repairs can be as extensive as replacement of structural components of the bridges including deck or wingwall replacements or as minor as bridge painting, curb and sidewalk replacement, traffic barrier upgrades, or repairs to the deck surfaces.

Bridge Scour Program

The Bridge Inspection Program and the Bridge Scour Analysis Program identify bridges susceptible to damage from stream scour. Stream scour occurs when fast moving water loosens the soil and rocks along streambanks and stream bottoms. Scouring is a natural occurrence that has carried soil and rocks downstream for millions of years. However, this stream action is magnified if the stream width is reduced by a bridge that has a narrow opening. The narrow opening constricts the flow and causes the stream velocity to speed up at the bridge crossing. This increased stream velocity can cause additional scour at the bridge by removing stable soil and rocks from under the bridge supports.

Under the Bridge Scour Program, Harford County identifies bridges susceptible to scour and repairs them with concrete toewalls, rip-rap (large rocks), gabions (small rocks enclosed in rectangular wire baskets) or a combination of the three repairs. This work stabilizes the foundation and adds life to the bridge.

Environmental Considerations

Most Harford County maintained bridges cross over streams. Therefore, bridge replacement, bridge rehabilitation, and bridge repair projects can affect local streams or Chesapeake Bay. Harford County works with many federal and state agencies and individuals to determine that the environment and adjacent properties are not adversely affected. Some of these agencies and the reasons for working with the agencies are listed below: