Why are Bridge Safety Inspections Important?
Did you know that the Commonwealth of Pennsylvania owns and maintains over 25,000 bridges? In addition, there are over 6,400 bridges owned by local Municipalities in Pennsylvania.
Bridge safety is key to the traveling public. Bridges can fail for several reasons including, deterioration, collision damage, erosion/scour of the foundations and extreme events (earthquake, high winds, flooding). Failure of a bridge can cause loss of life, impact the public’s ability to travel to their desired destination, prohibit the delivery of goods, and in general impact the daily routine of numerous individuals.
Based on past failures of bridges on the transportation system, the National Bridge Inspection Standards (NBIS) were developed and became effective in the 1970s. The Federal Highway Administration oversees the NBIS and provides guidance for bridge inspection requirements.
All State, County, City, Township, Borough, etc. owned bridges on public roads that are greater than 20’ in length and carry traffic must be routinely inspected at predetermined cycles. Bridges in good condition typically have an inspection cycle of two years, which is the maximum amount of time allowed between inspections. However, certain conditions may require a bridge to be inspected at more frequent intervals as short as 6 months. Bridges of 20’ or less in length are not required to be inspected under the NBIS; however, routine inspections to ensure safety of the bridge are recommended. The Pennsylvania Department of Transportation (PennDOT) takes a proactive approach to State owned bridges with span lengths between 8’ and 20’ and performs routine inspection on them even though it is not required. PennDOT does not require Municipal bridge owners to inspect bridges with span lengths of 20’ or less. Bridges privately owned and bridges not on public roads such as railroad bridges and pedestrian bridges are not included in the NBIS and are not subject to its requirements; however, inspections of privately owned bridges are encouraged for safety reasons.
Bridge inspections that are required by the NBIS must be performed by Certified Bridge Safety Inspectors. The inspection team typically consists of two individuals, but larger bridges may have additional inspectors. Some bridges can be inspected from the ground or with use of a ladder. Others may require different types of rigging and/or snooper trucks to be able to closely access all of the bridge components. All inspectors must are required to be certified. Certification as a bridge safety inspector requires several things including, successfully completing prerequisite trainings to develop a general understanding of bridge structures, attending an initial 3 week training course and successfully completing the certification test at the end of the course. After becoming certified, inspectors must attend recertification courses every two years and successfully pass the recertification test at the end of the course. Being licensed as a Professional Engineer is not required to be a Certified Bridge Safety Inspector; however, many Certified Bridge Safety Inspectors are licensed Professional Engineers.
Typical bridge inspections consist of a review of the overall structure including, but not limited to items such as the substructure units, beams, traffic barriers and guide rail, waterway opening, erosion/scour of the streambed, approach roadway, and required signage to assess its condition. Any and all deficiencies observed during the inspection are noted and recorded. If significant deficiencies are noted, the bridge inspection will notify the bridge owner to take action to correct the deficiencies. If deterioration of a bridge component is observed, a load rating analysis of the bridge may be required. The load rating is performed by a Professional Engineer registered in the Commonwealth of Pennsylvania. Load rating analysis may require that the bridge be posted for a restrictive weight limit to ensure safe passage of heavier vehicles or even be closed to traffic until repairs can be made to the bridge allowing the bridge to be reopened.
The EADS Group (EADS) has 11 Certified Bridge Safety Inspectors on staff. EADS has provided bridge inspections for over 25 years and routinely inspects an average of 200 bridges annually. EADS provides this service for PennDOT and numerous municipal clients. EADS can assist you with your bridge needs regardless of the size. No bridge is too big or too small.