§ 650.305 Definitions. The following terms used in this subpart are defined as follows: *AASHTO Manual.* The term “AASHTO Manual” means the American Association of State Highway and Transportation Officials (AASHTO) “Manual for Bridge Evaluation”, including Interim Revisions, excluding the 3rd paragraph in Article 6B.7.1, incorporated by reference in § 650.317.
*Attribute.* Characteristic of the design, loading, conditions, and environment that affect the reliability of a bridge or bridge member.
*Bridge.* A structure including supports erected over a depression or an obstruction, such as water, highway, or railway, and having a track or passageway for carrying traffic or other moving loads, and having an opening measured along the center of the roadway of more than 20 feet between under copings of abutments or spring lines of arches, or extreme ends of openings for multiple boxes; it includes multiple pipes, where the clear distance between openings is less than half of the smaller contiguous opening.
*Bridge inspection experience.* Active participation in bridge inspections in accordance with the this subpart, in either a field inspection, supervisory, or management role. Some of the experience may come from relevant bridge design, bridge load rating, bridge construction, and bridge maintenance experience provided it develops the skills necessary to properly perform a NBIS bridge inspection.
*Bridge inspection refresher training.* The National Highway Institute[1] (NHI) “Bridge Inspection Refresher Training Course” or other State, federally, or tribally developed instruction aimed to improve quality of inspections, introduce new techniques, and maintain consistency in the inspection program.
Bridge Inspector's Reference Manual or the BIRM. A comprehensive FHWA manual on procedures and techniques for inspecting and evaluating a variety of in-service highway bridges. This manual is available at the following URL: *www.fhwa.dot.gov/bridge/nbis.cfm .* This manual may be purchased from the Government Publishing Office, Washington, DC 20402 and from National Technical Information Service, Springfield, VA 22161.
*Complex feature.* Bridge component(s) or member(s) with advanced or unique structural members or operational characteristics, construction methods, and/or requiring specific inspection procedures. This includes mechanical and electrical elements of moveable spans and cable-related members of suspension and cable-stayed superstructures.
*Comprehensive bridge inspection training.* Training that covers all aspects of bridge inspection and enables inspectors to relate conditions observed on a bridge to established criteria (see the BIRM for the recommended material to be covered in a comprehensive training course).
*Consequence.* A measure of impacts to structural safety and serviceability in a hypothetical scenario where a deterioration mode progresses to the point of requiring immediate action. This may include costs to restore the bridge to safe operating condition or other costs.
*Critical finding.* A structural or safety related deficiency that requires immediate action to ensure public safety.
*Damage inspection.* An unscheduled inspection to assess structural damage resulting from environmental factors or human actions.
*Deterioration mode.* Typical deterioration or damage affecting the condition of a bridge member that may affect the structural safety or serviceability of the bridge.
*Element level bridge inspection data.* Quantitative condition assessment data, collected during bridge inspections, that indicates the severity and extent of defects in bridge elements.
*End-of-course assessment.* A comprehensive examination given to students after the completion of the delivery of a training course.
*Hands-on inspection.* Inspection within arm's length of the member. Inspection uses visual techniques that may be supplemented by nondestructive evaluation techniques.
*Highway.* The term “highway” is defined in 23 U.S.C. 101.
*In-depth inspection.* A close-up, detailed inspection of one or more bridge members located above or below water, using visual or nondestructive evaluation techniques as required to identify any deficiencies not readily detectable using routine inspection procedures. Hands-on inspection may be necessary at some locations. In-depth inspections may occur more or less frequently than routine inspections, as outlined in bridge specific inspection procedures.
*Initial inspection.* The first inspection of a new, replaced, or rehabilitated bridge. This inspection serves to record required bridge inventory data, establish baseline conditions, and establish the intervals for other inspection types.
*Inspection date.* The date on which the field portion of the bridge inspection is completed.
*Inspection due date.* The last inspection date plus the current inspection interval.
*Inspection report.* The document which summarizes the bridge inspection findings, recommendations, and identifies the team leader responsible for the inspection and report.
*Internal redundancy.* A redundancy that exists within a primary member cross-section without load path redundancy, such that fracture of one component will not propagate through the entire member, is discoverable by the applicable inspection procedures, and will not cause a portion of or the entire bridge to collapse.
*Inventory data.* All data reported to the National Bridge Inventory (NBI) in accordance with the § 650.315.
*Legal load.* The maximum load for each vehicle configuration, including the weight of the vehicle and its payload, permitted by law for the State in which the bridge is located.
*Legal load rating.* The maximum permissible legal load to which the structure may be subjected with the unlimited numbers of passages over the duration of a specified bridge evaluation period. Legal load rating is a term used in Load and Resistance Factor Rating method.
*Load path redundancy.* A redundancy that exists based on the number of primary load-carrying members between points of support, such that fracture of the cross section at one location of a member will not cause a portion of or the entire bridge to collapse.
*Load posting.* Regulatory signs installed in accordance with 23 CFR 655.601 and State or local law which represent the maximum vehicular live load which the bridge may safely carry.
*Load rating.* The analysis to determine the safe vehicular live load carrying capacity of a bridge using bridge plans and supplemented by measurements and other information gathered from an inspection.
*Nationally certified bridge inspector.* An individual meeting the team leader requirements of § 650.309(b).
*Nonredundant Steel Tension Member (NSTM).* A primary steel member fully or partially in tension, and without load path redundancy, system redundancy or internal redundancy, whose failure may cause a portion of or the entire bridge to collapse.
*NSTM inspection.* A hands-on inspection of a nonredundant steel tension member.
*NSTM inspection training.* Training that covers all aspects of NSTM inspections to relate conditions observed on a bridge to established criteria.
*Operating rating.* The maximum permissible live load to which the structure may be subjected for the load configuration used in the load rating. Allowing unlimited numbers of vehicles to use the bridge at operating level may shorten the life of the bridge. Operating rating is a term used in either the Allowable Stress or Load Factor Rating method.
*Private bridge.* A bridge open to public travel and not owned by a public authority as defined in 23 U.S.C. 101.
*Procedures.* Written documentation of policies, methods, considerations, criteria, and other conditions that direct the actions of personnel so that a desired end result is achieved consistently.
*Probability.* Extent to which an event is likely to occur during a given interval. This may be based on the frequency of events, such as in the quantitative probability of failure, or on degree of belief or expectation. Degrees of belief about probability can be chosen using qualitative scales, ranks, or categories such as, remote, low, moderate, or high.
*Professional engineer (PE).* An individual, who has fulfilled education and experience requirements and passed examinations for professional engineering and/or structural engineering license that, under State licensure laws, permits the individual to offer engineering services within areas of expertise directly to the public.
*Program manager.* The individual in charge of the program, that has been assigned the duties and responsibilities for bridge inspection, reporting, and inventory, and has the overall responsibility to ensure the program conforms with the requirements of this subpart. The program manager provides overall leadership and is available to inspection team leaders to provide guidance.
*Public road.* The term “public road” is defined in 23 U.S.C. 101.
*Quality assurance (QA).* The use of sampling and other measures to assure the adequacy of QC procedures in order to verify or measure the quality level of the entire bridge inspection and load rating program.
*Quality control (QC).* Procedures that are intended to maintain the quality of a bridge inspection and load rating at or above a specified level.
*Rehabilitation.* The major work required to restore the structural integrity of a bridge as well as work necessary to correct major safety defects.
*Risk.* The exposure to the possibility of structural safety or serviceability loss during the interval between inspections. It is the combination of the probability of an event and its consequence.
*Risk assessment panel (RAP).* A group of well experienced panel members that performs a rigorous assessment of risk to establish policy for bridge inspection intervals.
*Routine inspection.* Regularly scheduled comprehensive inspection consisting of observations and measurements needed to determine the physical and functional condition of the bridge and identify changes from previously recorded conditions.
*Routine permit load.* A live load, which has a gross weight, axle weight, or distance between axles not conforming with State statutes for legally configured vehicles, authorized for unlimited trips over an extended period of time to move alongside other heavy vehicles on a regular basis.
*Safe load capacity.* A live load that can safely utilize a bridge repeatedly over the duration of a specified inspection interval.
*Scour.* Erosion of streambed or bank material due to flowing water; often considered as being localized around piers and abutments of bridges.
*Scour appraisal.* A risk-based and data-driven determination of a bridge's vulnerability to scour, resulting from the least stable result of scour that is either observed, or estimated through a scour evaluation or a scour assessment.
*Scour assessment.* The determination of an existing bridge's vulnerability to scour which considers stream stability and scour potential.
*Scour critical bridge.* A bridge with a foundation member that is unstable, or may become unstable, as determined by the scour appraisal.
*Scour evaluation.* The application of hydraulic analysis to estimate scour depths and determine bridge and substructure stability considering potential scour.
*Scour plan of action (POA).* Procedures for bridge inspectors and engineers in managing each bridge determined to be scour critical or that has unknown foundations.
*Service inspection.* An inspection to identify major deficiencies and safety issues, performed by personnel with general knowledge of bridge maintenance or bridge inspection.
*Special inspection.* An inspection scheduled at the discretion of the bridge owner, used to monitor a particular known or suspected deficiency, or to monitor special details or unusual characteristics of a bridge that does not necessarily have defects.
*Special permit load.* A live load, which has a gross weight, axle weight, or distance between axles not conforming with State statutes for legally configured vehicles and routine permit loads, typically authorized for single or limited trips.
*State transportation department.* The term “State transportation department” is defined in 23 U.S.C. 101.
*System redundancy.* A redundancy that exists in a bridge system without load path redundancy, such that fracture of the cross section at one location of a primary member will not cause a portion of or the entire bridge to collapse.
*Team leader.* The on-site, nationally certified bridge inspector in charge of an inspection team and responsible for planning, preparing, performing, and reporting on bridge field inspections.
*Temporary bridge.* A bridge which is constructed to carry highway traffic until the permanent facility is built, repaired, rehabilitated, or replaced.
*Underwater bridge inspection diver.* The individual performing the inspection of the underwater portion of the bridge.
*Underwater Bridge Inspection Manual.* A comprehensive FHWA manual on the procedures and techniques for underwater bridge inspection. This manual is available at the following URL: *www.fhwa.dot.gov/bridge/nbis.cfm .* This manual may be purchased from the Government Publishing Office, Washington, DC 20402 and from National Technical Information Service, Springfield, VA 22161.
*Underwater bridge inspection training.* Training that covers all aspects of underwater bridge inspection to relate the conditions of underwater bridge members to established criteria (see Underwater Bridge Inspection Manual and the BIRM section on underwater inspection for the recommended material to be covered in an underwater bridge inspection training course).
*Underwater inspection.* Inspection of the underwater portion of a bridge substructure and the surrounding channel, which cannot be inspected visually at low water or by wading or probing, and generally requiring diving or other appropriate techniques.
*Unknown Foundations.* Foundations of bridges over waterways where complete details are unknown because either the foundation type and depth are unknown, or the foundation type is known, but its depth is unknown, and therefore cannot be appraised for scour vulnerability.
Footnotes -
650.305
[1] The NHI training may be found at the following URL: *www.nhi.fhwa.dot.gov/ .*