“Manual for Railway Engineering”' published by the American Railway Engineering Association (AREA). These specifications incorporate recognized principles of structural design and analysis. They are continually reviewed and revised by committees of competent engineers. Other specifications for design and rating, however, have been successfully used by some railroads and may also be suitable now. (b) A bridge can be rated for capacity according to current specifications regardless of the specification to which it was originally designed.
6. Periodic inspections.
(a) Periodic bridge inspections by competent inspectors are necessary to determine whether a structure conforms to its design or rating condition and, if not, or the degree of nonconformity. (b) The prevailing practice throughout the railroad industry is to inspect railroad bridges at least annually. Inspections at more frequent intervals may be indicated by the nature or condition of a structure or intensive traffic levels.
7. Underwater inspections.
(a) Inspections of bridges should include measuring and recording the condition of substructure support at locations subject to erosion from moving water. (b) Stream beds are often not visible to the inspector. Indirect measurements by sounding, probing, or any other appropriate means are necessary in those cases. A series of records of those readings will provide the best information should unexpected changes suddenly occur. Where such indirect measurements do not provide the necessary assurance of foundation integrity, diving inspections should be performed as prescribed by a competent engineer.
8. Special inspections.
(a) A special bridge inspection should be performed after an occurrence that might have reduced the capacity of the bridge, such as a flood, a derailment, or an unusual impact. (b) When a railroad learns that a bridge might have suffered damage through an unusual occurrence, it should restrict train operation over the bridge until the bridge can be inspected and evaluated.
9. Inspection records.
(a) Bridge inspections should be recorded. Records should identify the structure inspected, the date of the inspection, the name of the inspector, the components inspected, and their condition. (b) Information from bridge inspection reports should be incorporated into a bridge management program to ensure that exceptions on the reports are corrected or accounted for. A series of inspection reports over time should be maintained so as to provide a valuable record of trends and rates of degradation of bridge components. The reports should be structured to promote comprehensive inspections and effective communication between an inspector and an engineer who performs an analysis of a bridge. (c) An inspection report should be comprehensible to a competent person without interpretation by the reporting inspector.
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