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Bridge Inspection Practices (2007)

Chapter: Chapter Four - Inspection Types and Intervals

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Suggested Citation:"Chapter Four - Inspection Types and Intervals." National Academies of Sciences, Engineering, and Medicine. 2007. Bridge Inspection Practices. Washington, DC: The National Academies Press. doi: 10.17226/14127.
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Suggested Citation:"Chapter Four - Inspection Types and Intervals." National Academies of Sciences, Engineering, and Medicine. 2007. Bridge Inspection Practices. Washington, DC: The National Academies Press. doi: 10.17226/14127.
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Suggested Citation:"Chapter Four - Inspection Types and Intervals." National Academies of Sciences, Engineering, and Medicine. 2007. Bridge Inspection Practices. Washington, DC: The National Academies Press. doi: 10.17226/14127.
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Suggested Citation:"Chapter Four - Inspection Types and Intervals." National Academies of Sciences, Engineering, and Medicine. 2007. Bridge Inspection Practices. Washington, DC: The National Academies Press. doi: 10.17226/14127.
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Suggested Citation:"Chapter Four - Inspection Types and Intervals." National Academies of Sciences, Engineering, and Medicine. 2007. Bridge Inspection Practices. Washington, DC: The National Academies Press. doi: 10.17226/14127.
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Suggested Citation:"Chapter Four - Inspection Types and Intervals." National Academies of Sciences, Engineering, and Medicine. 2007. Bridge Inspection Practices. Washington, DC: The National Academies Press. doi: 10.17226/14127.
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Suggested Citation:"Chapter Four - Inspection Types and Intervals." National Academies of Sciences, Engineering, and Medicine. 2007. Bridge Inspection Practices. Washington, DC: The National Academies Press. doi: 10.17226/14127.
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Suggested Citation:"Chapter Four - Inspection Types and Intervals." National Academies of Sciences, Engineering, and Medicine. 2007. Bridge Inspection Practices. Washington, DC: The National Academies Press. doi: 10.17226/14127.
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Suggested Citation:"Chapter Four - Inspection Types and Intervals." National Academies of Sciences, Engineering, and Medicine. 2007. Bridge Inspection Practices. Washington, DC: The National Academies Press. doi: 10.17226/14127.
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Suggested Citation:"Chapter Four - Inspection Types and Intervals." National Academies of Sciences, Engineering, and Medicine. 2007. Bridge Inspection Practices. Washington, DC: The National Academies Press. doi: 10.17226/14127.
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Suggested Citation:"Chapter Four - Inspection Types and Intervals." National Academies of Sciences, Engineering, and Medicine. 2007. Bridge Inspection Practices. Washington, DC: The National Academies Press. doi: 10.17226/14127.
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Suggested Citation:"Chapter Four - Inspection Types and Intervals." National Academies of Sciences, Engineering, and Medicine. 2007. Bridge Inspection Practices. Washington, DC: The National Academies Press. doi: 10.17226/14127.
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Suggested Citation:"Chapter Four - Inspection Types and Intervals." National Academies of Sciences, Engineering, and Medicine. 2007. Bridge Inspection Practices. Washington, DC: The National Academies Press. doi: 10.17226/14127.
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Suggested Citation:"Chapter Four - Inspection Types and Intervals." National Academies of Sciences, Engineering, and Medicine. 2007. Bridge Inspection Practices. Washington, DC: The National Academies Press. doi: 10.17226/14127.
×
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Suggested Citation:"Chapter Four - Inspection Types and Intervals." National Academies of Sciences, Engineering, and Medicine. 2007. Bridge Inspection Practices. Washington, DC: The National Academies Press. doi: 10.17226/14127.
×
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Suggested Citation:"Chapter Four - Inspection Types and Intervals." National Academies of Sciences, Engineering, and Medicine. 2007. Bridge Inspection Practices. Washington, DC: The National Academies Press. doi: 10.17226/14127.
×
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Suggested Citation:"Chapter Four - Inspection Types and Intervals." National Academies of Sciences, Engineering, and Medicine. 2007. Bridge Inspection Practices. Washington, DC: The National Academies Press. doi: 10.17226/14127.
×
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Suggested Citation:"Chapter Four - Inspection Types and Intervals." National Academies of Sciences, Engineering, and Medicine. 2007. Bridge Inspection Practices. Washington, DC: The National Academies Press. doi: 10.17226/14127.
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26 U.S. INSPECTIONS U.S. federal regulations define eight types of bridge inspec- tions (Table 34). Three of these, fracture-critical member inspection, routine inspection, and underwater inspection occur at intervals set by regulation. For routine inspection and underwater inspection, U.S. federal regulations cite three intervals: A standard interval; a longer interval applied to specific bridges and with the approval of the FHWA; and any interval, shorter than stan- dard, that may be needed at a bridge. For fracture-critical member inspections, a standard interval and shorter interval, if needed, are stated in regulation (Table 35). NBI data from 2005 (2) show that state DOTs use standard intervals for 85% of routine inspections, 34% of underwater inspections, and 67% of fracture-critical member inspections (Table 36). Inspection intervals from NBI data are listed for routine inspections (see Tables 37 and F1), underwater inspections (see Tables 38 and F2), and fracture-critical inspections (see Tables 39 and F3). Throughout this chapter more detailed responses to the questions on inspection types and intervals can be found in the tables in Appendix F. Routine Inspection—U.S. Federal Regulations U.S. federal regulations define four aspects of routine in- spection of bridges: • Structures—regulations define the bridges and struc- tures that must be inspected. • Frequency—regulations set maximum intervals for inspections. • Inspectors—regulations set minimum qualifications for inspection program managers and inspection team leaders. • Procedures—regulations include, by reference, the Bridge Inspector’s Reference Manual (4) and the AASHTO Manual for Condition Evaluation of Bridges (5). Aspects of routine inspection that are determined by state DOTs, other bridge owners, and their inspection staff include: • Short-interval inspections of some structures. Interim inspections of structures or critical components of structures. • Access for inspections and policy for close-up and hands-on inspection. • Application of methods of testing and/or measurement including NDT methods. • Personnel requirements for complex structures, com- plex inspection methods, and/or complex access. This section presents practices at U.S. state DOTs related to routine inspections. Information was collected from 34 DOTs. Not all DOTs have information on every topic related to routine inspection. Routine Inspection—U.S. State Department of Transportation Practice Full routine inspection of bridges occurs at 24-month intervals at most state DOTs and for the majority of bridges. Two states, Minnesota and Ohio, require routine inspection at 12-month intervals. Minnesota allows a 24-month inspection interval for specific bridges with the approval of the DOT. As a result, rou- tine inspection intervals are 24 months for approximately 63% and 12 months for 28% of bridges in Minnesota. In Ohio, more than 99% of all bridges have routine inspections at 12-month intervals. Specific Tasks in Routine Inspections Seven DOTs reported policies on specific inspection meth- ods or measurements that must be collected at set intervals (see Table F4). Tasks include measurement of vertical clear- ances, measurement of channel cross section, fathometer surveys at substructures, mandatory wading at substructures, and mandatory boring of timber members. For bridges in good condition, intervals for tasks range from 60 to 144 months. Intervals become progressively shorter as bridge condition becomes poorer, as scour hazard is more severe, or as vertical clearances are more limited. Access Policies for Routine inspections Ten DOTs and Eastern Federal Lands reported policies regarding access to bridge components for routine inspection (see Table F5). Access can include climbing, rigging, UBIVs, and entry of confined spaces. Idaho, Iowa, Oregon, and Eastern Federal Lands set maximum intervals for close- up inspection, ranging from 48 to 120 months. The Oregon DOT requires entry of box girders during every routine CHAPTER FOUR INSPECTION TYPES AND INTERVALS

27 inspection if deterioration is known to exist. DOTs in other states track the need for access equipment at some bridges as a part of planning and scheduling for inspections. Routine Inspections for Specific Structures or Details Nineteen DOTs set intervals for inspection of specific bridge types and detail types (see Table F6). Intervals are set for inspection of pin and hanger details and fatigue-prone details on redundant bridges, for pontoons of floating bridges, for cables in cable-supported spans, and for segmental superstructures. Hands-On Inspection Thirty DOTs and Eastern Federal Lands reported policies for hands-on inspection during routine inspections. Policies range from general advice to making hands-on inspections as needed, to requirements for hands-on inspection at specific details or in response to specific defects (see Table F7). The Pennsylvania DOT sets a maximum 72-month interval for hands-on inspection of each component of a bridge. In-Depth Inspection Eight DOTs set maximum intervals for in-depth inspection of bridges (see Table F8). For bridges in good condition, intervals range from 10 to 15 years. DOT policy may require specific measurements, specific reports, and the use of spe- cific personnel for in-depth inspection. Long-interval in- depth inspections are thorough, detailed inspections of entire bridges. Short-interval in-depth inspections are applied to specific components such as nonredundant members or con- nections, and equipment for movable bridges. Underwater Inspection NBI data (2) indicate that although 84% of NBI-length bridges and culverts are water crossings, only 6% require in- Inspection Description Damage Inspection An unscheduled inspection to assess structural damage resulting from environmental factors or human actions. Fracture-Critical Member Inspection A hands-on inspection of a fracture-critical member or member components that may include visual and other nondestructive evaluation. Hands-On Inspection Inspection within arms length of the component. Inspection uses visual techniques that may be supplemented by NDT. In-Depth Inspection A close-up inspection of one or more members above or below the water level to identify any deficiencies not readily detectable using routine inspection procedures; hands-on inspection may be necessary at some locations. Initial Inspection First inspection of a bridge as it becomes a part of the bridge inventory to provide all Structure Inventory and Appraisal data and other relevant data and to determine baseline structural conditions. Routine Inspection Regularly scheduled inspection consisting of observations and/or measurements needed to determine the physical and functional condition of the bridge, to identify any changes from initial or previously recorded conditions, and to ensure that the structure continues to satisfy present service requirements. Special Inspection An inspection scheduled at the discretion of the bridge owner, used to monitor a particular known or suspected deficiency. Underwater Inspection Inspection of the underwater portion of a bridge substructure and the surrounding channel that cannot be inspected visually at low water by wading or probing, generally requiring diving or other appropriate techniques. Source: Code of Federal Regulations (1). Inspection Standard Interval Maximum Interval Fracture-Critical Member 24 months — Routine 24 months 48 months Underwater 60 months 72 months Inspection Short Interval Standard Interval Long Interval Fracture-Critical Member 26% 67% 7% Routine 11% 84% 5% Underwater 66% 34% <1% Source: 2005 NBI data (2). Bridges and Culverts Routine Inspection Interval, Months <12 12 24 36 48 Total 1,629 (0.3%) 60,363 (10.1%) 504,413 (84.8%) 19 (0.003%) 28,275 (4.8%) 595,149 (100%) Source: 2005 NBI data (2). Note: Not all inspection intervals are shown. TABLE 34 U.S. FEDERAL INSPECTION TYPES TABLE 36 U.S. INSPECTION INTERVALS IN PRACTICE TABLE 35 INSPECTION INTERVALS: U.S. FEDERAL REGULATIONS TABLE 37 INSPECTION INTERVALS—ROUTINE INSPECTION—SUMMARY

28 spection by diving. Thirty-eight percent of dive inspections are performed at intervals of 24 months or less, 26% are done at 48-month intervals, and 34% are done at 60-month inter- vals. Less than 1% of dive inspections are performed at the maximum 72-month interval currently permitted by U.S. federal regulations. Dive inspections are applied when inspection by wading and probing is not adequate (see Table F9). Seven DOTs reported a maximum depth of water for inspections by wad- ing or from boats. Maximum depths range from 30 in. to 6 ft. In deeper water, inspection must be by diving. Eight DOTs reported policies for short-interval underwater inspection. Inspection intervals are shorter for bridges with poor scour ratings and where scour protection is absent or inadequate. Five DOTs identified two or three intensity levels for dive inspections that differ in the extent of cleaning of submerged components. Channel cross sections may be measured during dive inspections. Fracture-Critical Inspection Inspection of fracture-critical members is required every 24 months by federal regulation. Three DOTs reported annual inspections of fracture-critical members, and four DOTs perform increased intensity inspections of fracture-critical members using intervals that range from 48 to 120 months. The shorter intervals are applied to older bridges, bridges with a greater volume of truck traffic, and bridges having specific design details. Longer intervals for increased inten- sity inspections are applied to newer bridges in good condi- tion with (relatively) robust design details (see Table F10). The Oregon DOT, for example, employs a Level 1 fracture- critical inspection that is done with every routine inspection, and a more intense Level 2 fracture-critical inspection at a longer interval. Level 2 inspections can include use of NDT methods. Complex Bridges U.S. federal regulations identify movable bridges and cable- supported bridges as examples of complex bridges. Inspec- tion of complex bridges may require special procedures or specially trained inspectors. Twenty-four DOTs identified some structures and inspec- tion types as complex or as needing special methods (Table 40). These are in addition to fracture-critical inspection and underwater inspections. Twenty-two DOTs require spe- cific training or experience in personnel for these inspections. The Connecticut DOT identifies bridge complexity in three levels and specifies inspection team size and technical grades of team members for each level of complexity. The Ohio DOT identifies major bridges by structural type and span length. Bridge types and inspection types that require specific training of personnel are listed in Table F11. Movable Bridges At movable bridges, additional inspections are made of motion equipment, motion operation, and signals and gates (see Table F12). Cursory inspections and trial operation of movable spans are made once each year at four DOTs. One DOT performs trial operations once each month. In-depth inspections of motion equipment are done at 72-month interval at two DOTs. Routine Interim Inspection Short-interval inspections, usually called interim inspec- tions, are performed in response to poor conditions, posting for load, scour vulnerability, fracture vulnerability, and for Bridges and Culverts Underwater Inspection Interval, Months Inspections (total) <12 12 24 36 48 60 72 >72 37,735 (100.00%) 2,209 (5.9%) 1,114 (3.0%) 11,092 (29.4%) 636 (1.7%) 9,835 (26.1%) 12,796 (34.0%) 4 (0.01%) 0 (0.0%) Source: 2005 NBI data (2). Note: Not all inspection intervals are shown. TABLE 38 INSPECTION INTERVALS—UNDERWATER INSPECTION—SUMMARY Bridges and Culverts Fracture Inspection Interval, Months Critical (total) <12 12 24 36 48 >48 21,668 (100.0%) 384 (1.8%) 5,292 (24.5%) 14,616 (67.6%) 16 (0.1%) 288 (1.3%) 1,023 (4.7%) Source: 2005 NBI data (2). Note: Not all inspection intervals are shown. TABLE 39 INSPECTION INTERVALS—FRACTURE-CRITICAL INSPECTION—SUMMARY Complex Bridge No. of DOTs Suspension 19 (59%) Cable-Stayed 17 (53%) Movable Bridge 14 (44%) Tied-Arch 13 (41%) Eyebar Bridge 8 (25%) Box Girder with External Post-Tensioning 8 (25%) Single Concrete Box Girder 7 (22%) Two-Girder 6 (19%) Single Steel Box Girder 6 (19%) Bridges with Pins and Hangers 6 (19%) Note: Percentage refers to how many of the 32 agencies that responded to the question mentioned inspecting this type of complex bridge. TABLE 40 U.S. COMPLEX BRIDGES

29 specific defects such as damage resulting from high-load hits, loss of bearing, the presence of temporary supports, and incipient buckling of members (see Table F13). DOT policy guidelines to interim inspections recognize: • Bridges posted for load (five DOTs); • Bridges with low NBI condition ratings (seven DOTs)— This usually means condition ratings for deck, super- structure, substructure, and culvert; however, some DOTs include ratings for channel and approach roadway as well; • High-load hits, unrepaired critical findings, severe section loss, or other known significant defects (seven DOTs); and • Temporary bridges and bridges with temporary sup- ports or temporary repairs (three DOTs). Interim inspections focus on the specific defect, specific poor condition, or specific cause of load posting. Intervals for interim inspections range from 6 to 24 months, with shorter intervals for more severe deficiencies. Note that interim inspections at 24 months alternate with rou- tine inspections also at 24 months. In this way, defects are inspected every 12 months. Forty-Eight-Month Routine Inspection DOTs in Arizona, Illinois, and New Mexico apply a 48-month interval for routine inspection at more than one-third of their bridges (2) (Table 41). Five other DOTs, Colorado, Kentucky, Montana, North Dakota, and West Virginia use a 48-month interval for at least 10% of their bridges. Thirty-six DOTs use a 48-month interval for less than 1% of their bridges. Forty-eight-month inspection intervals are applied only to bridges in good condition. Some DOTs set bounds on bridge length, bridge age, load capacity, or vertical clearance to qualify for a 48-month inspection interval (see Table F14). Special Inspections Eleven DOTs identified as “special” a variety of inspections directed at particular types of structures, addressing specific defects or performing specific tasks. Table F15 lists inspec- tions that collect specific quantitative data, but might not be periodic. These inspections include measurement of joint opening, crack extent, substructure settlement, vertical clearance after overlays are placed, and inspection of sub- structures and channels after storms or other high-flow events. Minor Bridges and Non-Bridges Information on routine inspection of minor bridges, non- highway bridges, and non-bridges was collected from 13 state DOTs (see Table F16). Tennessee and Washington State DOTs inspect roadway bridge spans as short as 4 ft. The Virginia DOT inspects all structures with openings of 36 square feet or greater. DOTs inspect or require the in- spection of pedestrian bridges, railroad bridges, utility bridges, and private bridges that cross public roads. Inspec- tion may be limited to the highway environs, and may focus on potential hazards to road traffic. DOTs also inspect sign structures, high-mast lights, retaining walls, noise barriers, tunnels, and ferry slips. Intervals for routine inspection gen- erally range from 24 to 72 months. At ferry terminals, vehi- cle transfer spans and equipment for hoists may be inspected annually. Informal Inspections U.S. DOTs responding to the questionnaire all indicated that external reports of problems at bridges are investigated by bridge inspectors (see Table F17). Thirteen DOTs preserve external reports as hardcopy in bridge files. Twelve DOTs routinely receive problem reports from state maintenance crews. In North Carolina, findings from annual highway reviews (ride-bys) performed by maintenance crews are shared with bridge inspectors. In Vermont, annual reports of the DOT’s Operation Division are shared. In Iowa, there is frequent, informal contact among inspectors and mainte- nance crews, and frequent exchange of information. Monitoring of Bridges Table F18 presents bridge monitoring methods for 31 U.S. DOTs and Eastern Federal Lands. Methods of monitoring are identified as visual monitoring, measurement, and instrumen- tation. Visual monitoring (15 DOTs) is often not periodic, is directed at one or very few defects, might be performed by maintenance crews or others, and is not recorded as an indi- vidual inspection. Measurement (22 DOTs) is the collection, usually by hand methods, of quantitative values during rou- tine inspections. Instrumentation (10 DOTs) is the application of acoustic detectors, strain gages, or other devices for precise and/or remote collection of quantitative data. DOT Percentage of Routine Inspections at 48-Month Interval Arizona 44 Illinois 42 New Mexico 35 West Virginia 24 Kentucky 17 Montana 16 Colorado 14 North Dakota 10 Texas 9 South Dakota 7 Connecticut 6 Washington 6 Arkansas 5 Virginia 5 Mississippi 1 Oklahoma 1 TABLE 41 PREVALENCE OF 48-MONTH IN- SPECTION INTERVAL

30 INSPECTION TYPES—FOREIGN ROAD AGENCIES Denmark The Danish Road Directorate identifies eight types of bridge inspections (Table 42). • Inventory inspections are made for new bridges, after major projects on bridges, and in general after each sig- nificant construction or repair event in the service life of a bridge. • Daily inspections are made by road maintenance crews. Each day, the highway road patrol performs a drive-by inspection of all national roads, noting distress in bridges, pavements, and all other road facilities. Crews observe each bridge in all weather conditions and develop a thorough familiarity with each structure and its basic systems. Daily inspections note: – Failure of load-bearing components; – Impact damage; – Washing away of slopes, shoulders, etc.; – Vandalism on slope facings, railings, traffic signals, lights, etc.; – Detached objects; for example, fragments of concrete, railing segments, and goods that have fallen off lorries; – Function of drainage systems; – Conditions of road surface; and – Winter conditions; accumulation of ice and snow. Daily inspections are not recorded in the bridge database. • Routine inspections are done once a year by the mainte- nance foreman or the bridge engineer for the road man- agement authority. The inspector must stop and view the bridge from the deck and from below. The inspector ver- ifies that recommended cleaning and routine mainte- nance have been done and makes further recommenda- tions for cleaning and maintenance for the next year. Maintenance work that is not complicated and of modest cost (around $20,000 U.S. maximum) is programmed through Danbro, the Danish bridge management system, and done by maintenance contractors. Maintenance con- tractors are supervised by the Directorate’s regional bridge inspector. Routine inspection notes: – Stoppage of drainage systems; Inspection Type Description Interval Inspector Inventory Collect bridge data and baseline conditions At new construction, and after every major repair project Bridge inspector Dailya Cursory examination noting failure, damage, debris, etc. Daily Road maintenance crewb Routine— Extended Planning and checking routine cleaning and maintenance Inspectors stop and view the structure from the top and bottom Damage, if any, is noted. Annually Consultant bridge inspector Reports from Users Reports of: impact damage vandalism debris on bridge or road erosion damage In response to user report Principal Thorough and systematic visual inspection of all the components of the bridge 6 years or lessc Directorate bridge inspector Special Collection of more detailed information for decisions on maintenance actions In response to recommendation from routine inspection Consultant bridge inspector Economic Special Inspection Preparation for major repair project for a bridge Development and comparison of remedial strategies In advance of project selection and development Consultant bridge inspector Technical Special Inspection Damage investigations Special investigations Load-carrying capacity evaluations In response to extreme event, or suspect capacity Consultant bridge inspector aNot a formal part of the Directorate bridge inspection program. bSpecially trained personnel. Currently provided by contractors, but Directorate personnel were scheduled to take over this work in 2007. cApproximately 5% of Directorate bridges have Principal inspections at intervals of less than 6 years. TABLE 42 TYPES OF BRIDGE INSPECTIONS—DENMARK

31 – Grit and dirt, especially along edge-beams, gutters, low points, expansion joints, etc.; – Unwanted vegetation; – Erosion on slopes, washing away of foundations, hindrances, and deposits in watercourses; – Settlements at abutments and around manholes; and – A need for preventive maintenance (e.g., surface pro- tection of concrete). • Reports from highway users can require special visits to bridges. Often these reports deal with impact damage, vandalism, debris on the road, and erosion damage. • Principal inspections are thorough visual inspections of all components. The inspector assigns condition ratings to all components. Principal inspections are usually per- formed at 6-year intervals, but may be undertaken at shorter intervals. The inspector notes damage, reports the apparent causes of damage, and evaluates the risk to users. The inspectors recommend the interval to the next Principal inspection and may recommend additional spe- cial inspections. The interval to the next inspection de- pends on the bridge age, average daily traffic, location, existing conditions, and special features. Recommenda- tions for maintenance and repair are made, with the in- spector estimating the cost for each recommendation and indicating when the recommendation should be com- pleted (within 1 year, 2 years, or as many as 11 years into the future). • Special inspections collect more detailed information about specific conditions at bridges. • Economic special inspections provide information needed for selection of repair strategy and development of plans. • Technical special inspections are detailed investiga- tions of damage seeking causes of damage and evaluat- ing the effect of damage on load capacity. Finland Finland defines seven types of routine bridge inspection (see Table 43). • Acceptance inspections are done to add or modify bridge inventory data (the Finnish term is “registry data”). Ac- ceptance inspections occur for newly constructed bridges and after major repair or modification projects. • Annual inspections are performed by road maintenance foremen, or consultants hired by road foremen, and seek conditions that are a threat to safety. • General inspections are thorough visual inspections performed every 5 years for most bridges, and every 8 years for large bridges. All bridge components are assigned condition ratings, and inspection data are entered in the bridge registry. General inspections are done by certified bridge inspectors. • Basic inspections are similar to General inspections, but are performed on a select population of 125 bridges called reference bridges. Data from basic inspections and the accompanying materials tests are the basis of the formation and updating of bridge deterioration models. Basic inspections are performed by degreed engineers who are certified bridge inspectors. • Special inspections collect complete, detailed informa- tion in preparation for repair projects. Special inspec- tions are usually done by certified inspectors who are degreed engineers and have experience with the testing methods that may be needed at particular structures. • Underwater (dive) inspections are done by certified in- spectors with special training. Bridge components are inspected both visually and by touch. • Intensified monitoring, a kind of interim inspection, is performed on selected components and may be done by bridge inspectors, engineers, or road foremen depend- ing on the nature of the monitoring program. For long-span bridges in good condition, general inspec- tions are performed at 8-year intervals. The inspection of a long-span bridge is a complex effort that requires lane clo- sures and lift equipment. Long-span bridges usually have high traffic volume. Inspections are intentionally more intense at large bridges, with the increased scrutiny permit- ting the longer inspection interval. For most bridges, inspection intervals are determined by two factors. One is the bridge; inspection intervals are con- sistent with the condition of each bridge. The other is logis- tics; bridges in remote areas are inspected when personnel are on hand; therefore, inspection intervals may be somewhat longer or shorter than intended. France France has four types of routine inspections: routine visit, annual inspection, IQOA (Image de la qualité des Ouvrages d’Art: Image of the Quality of Bridges, Walls, and Tunnels) evaluation, and detailed inspection (Table 44). Routine visits are made by road agents during their patrols. Annual inspections are cursory examinations intended to discover new, significant defects in structures, and to program routine maintenance. IQOA evaluations occur every three years and are more complete visual examinations of struc- tures to establish the condition of bridges in IQOA classes. Detailed inspections occur at intervals ranging from 3 to 9 years, depending on bridge condition, and are thorough visual examinations of bridges noting all defects. The de- tailed inspection is a “blank slate” examination. The annual inspection, in contrast, is a check of defects known to exist at the structure. Annual inspections and IQOA inspections often require about one-half day of work for the inspection team. Detailed inspections require additional time and usually require access using lane closures, lift equipment, etc. The detailed inspection is a hands-on inspection. This is mandatory; the inspector must be able to touch each component.

32 Germany Germany performs bridge inspections at two levels called Major Test and Minor Test (15) (Table 45). Major tests are arms-length (DIN wording is “touching-distance”) inspec- tions of all elements with access to all parts. This entails opening access doors and covers, using lift equipment, per- forming underwater inspection, and inspecting the riverbed. Lane closures are used, if necessary, but use is limited by the large traffic volume on most federal roads. Major tests are performed at acceptance of construction, near the end of the guarantee period, and every six years during service life. Minor tests are done three years after each major test. Minor tests use findings of the previous major test and focus on known damage and defects. Access equipment is not used in a Minor test, but the level of effort is expanded as necessary for the conditions that are observed. Tests of electrical and me- chanical equipment, such as ventilation systems, are required by statute. All highway structures are visited twice a year for safety. Viewing is from the ground level as well as the traffic level. Germany performs ad hoc inspections after significant events such as storms or floods. Inspection Type Description Interval Inspector Acceptance Collect data for bridge registry Inspection of all components at arms length First general inspection of a large bridge After construction or repair work District bridge engineer Bridge engineer and designer Annual Cursory inspection for safety 1 year Road foreman or maintenance consultant General Inspection of all components at arms-length Results are stored in the Bridge Registry by the inspectors themselves. 4 to 8 years (usually 5 years) Certified bridge inspector Inspection of all components at arms-length NDT methods are used when necessary Results are stored in the Bridge Registry by the inspectors themselves. Large waterway bridges 8 years Certified inspector with engineering degree Basic For reference bridge group Inspection of all components Includes material sampling and testing to improve deterioration models 5 years Certified inspector with engineering degree Special Methods vary with needs of project For planning and development of repair projects Certified inspector with engineering degree Machinery of movable bridges; includes annual maintenance 1 year Specialist Suspension cables, stay cables 15 years Certified bridge inspection, specialist in cables Underwater Inspection by diving; visual and touch inspection of components 5 years Certified inspectors with special training Intensified Monitoring More frequent inspection Due to poor or weakened condition TABLE 43 TYPES OF BRIDGE INSPECTIONS—FINLAND

33 The names of inspection types are used a bit differently in the German preservation and maintenance guide (15) (Table 46). German structural design practice requires explicit con- sideration of access for inspection. Germany’s guide to de- sign for monitoring, inspection, and maintenance (16) directs designers to consider: • Visibility of parts; • Internal clearances in boxes; • Interior ventilation; • Installation of fixed ladders; • Lighting, both exterior and interior; and • Room for jacking points at abutments. Norway The Norwegian Public Roads Administration (17) identifies three classes and seven types of inspection (Table 47). • Acceptance inspections are performed for new con- struction and after major repair projects. Inspection Type Description Interval Performed by Major Test Arms-length inspection of all components; uses access equipment and includes underwater inspection 6 years Bridge inspector Acceptance Major test After new construction or major rehabilitation Guarantee Major test Near the end of the guarantee period Minor Test Verification of current state of known damage and defects 3 years after Major test Bridge inspector Superficial Cursory inspection for safety 3 months Road maintenance crew Ad Hoc After significant events, such as storms, floods, etc.; also for known, severe damage. N/A Depends on situation Systems Inspection of electrical or mechanical systems As required by regulation N/A = not applicable. TABLE 45 TYPES OF BRIDGE INSPECTIONS—GERMANY Inspection Type Interval Performed by Description Routine Visit Frequent Road maintenance agents employed by DDE Drive-by inspection Annual 1 year Road maintenance agents employed by DDE Cursory examination during visit to bridge IQOA 3 years Inspection agent sometimes with certified inspector Visual verification of conditions focusing on known defects 9 years Robust bridges. Arms-length visual examination of all components and noting all defects 6 years Normal bridges. Arms-length visual examination of all components and noting all defects 3 years Ill bridges. Arms-length visual examination of all components and noting all defects Detailed 1 year Certified inspector Very ill bridges. Arms-length visual examination of all components and noting all defects Underwater 6 years Certified inspector Certified inspector Certified inspector Certified inspector Diver making arms-length touch and visual inspection DDE = Direction Départementale de líEquipment. TABLE 44 TYPES OF BRIDGE INSPECTIONS—FRANCE

34 – Warranty inspections are performed near the end of the warranty period for construction or repairs. • Routine – General inspections every 1 or 2 years, and – Major inspections every 5 to 10 years. Structural cables are inspected every 5 years. • Additional Special inspections for known damage or after extreme events are performed as needed. Norway specifies the field measurements and materials tests that are part of each type of inspection (Table 48). General inspections require few measurements and no materials testing. Major inspections require many measurements and tests. South Africa South African practice includes three types of routine inspec- tions: Monitoring, Principal, and Verification (Table 49). Mon- itoring inspections are performed by maintenance personnel and occur at frequent but irregular intervals. Maintenance per- sonnel report problems, if any, but do not otherwise report that specific bridges have been visited. Monitoring inspections are part of routine maintenance surveys for road sections and also part of quick surveys conducted after accidents, floods, cyclones, or other extreme events. Principal inspections are conducted every 5 to 6 years by inspectors who are experienced in bridge design, maintenance, or rehabilitation. Principal inspections are thorough examina- tions of bridges that record all defects. A principal inspection produces a full inspection report with photographs. The 5-year interval for principal inspections matches SANRAL’s 5-year programming cycle for bridge repairs. Verification inspections are part of SANRAL’s QA pro- gram. Each year some bridges are selected and their condi- tions are verified by a senior bridge inspector. Two event-related inspections pertain to repair projects. (1) The project-level inspection is a directed examination of a bridge to collect data needed for the preparation of contract documents for a repair project; and (2) an acceptance inspec- tion is made after repairs are complete. Condition data from principal inspections are stored in the bridge database. Monitoring inspections do not produce con- dition ratings. Designation Description H1 Main inspection before acceptance H2 Main inspection before the expiration of the claims deadline for defects H Main inspection E Simple inspection S1–S9 Special inspections (inspection owing to particular reasons) Class Type Description Acceptance inspection Performed for new construction and after major repair projects Note deficiencies and damage Identify sources of deterioration that may be significant to maintenance First Warranty inspection Performed near the end of the warranty period Verify that repairs required by acceptance inspection are complete Note additional deficiencies and damage Identify additional sources of deterioration that may be of significance to maintenance General inspection Check for any serious damage affecting the load capacity, traffic safety, future maintenance, or environment/aesthetics Major inspection Inspection of all components Determine needs for maintenance or repair Estimate costs of maintenance or repair Measurements and material sampling as needed Major inspection— Cables Inspection of cables, hangers, clamps and anchorage points Verify adequacy and function of cable systems Determine maintenance needs and costs Routine Major inspection— Underwater Dive inspection Inspect submerged components Inspect the river bed Determine maintenance needs and costs Additional Special inspection Diverse purposes: investigation of known damage development of repair/rehabilitation projects checking after extreme events checking after problems at bridges of similar type TABLE 46 INSPECTION DESIGNATIONS—GERMANY TABLE 47 TYPES OF BRIDGE INSPECTIONS—NORWAY

35 Acceptance Inspection Warranty Inspection General Inspection Major Inspection Major Inspection Cable Major Inspection Underwater Special Inspection Measurements Bearing elevations X X Horizontal distances/displacement X X X X Thickness of wearing surfaces X X X X X Track wear X X X X X X Evenness X Sag X X X X Recording bridge details X X X Headroom X X X Materials Investigations—Concrete Rebar location and cover X X X Depth of carbonization X Chloride content X X X X X Corrosion investigation (ECP) X Structural analysis X Inspection of bracing cables X Cutting open the concrete to assess corrosion level X Materials Investigations—Steel Check bolt torque X Check rivets X Check welds X X-ray check X Ultrasound check X Magnetic powder check X Fiber optics X Ultrasound measurement of material thickness X Materials Investigations—Stone and Wood Humidity check (wood) X Fungus and rot check (wood) X Compressive strength X Checking Surface Coating Thickness of surface coating (concrete) X X Adhesive bonding between surface coating and concrete X X Thickness of surface coating (steel) X X Adhesive bonding between surface coating and steel X X Condition of surface coating (wood) X X Inspection Type Interval Performed by Description Monitoring At least once each year, usually more frequently Maintenance personnel Quick look for new defects and status of known defects Principal 5 years Inspectors experienced in bridge design or maintenance Full report with photographs of defects Verification ~60 bridges per year Senior bridge inspector QA effort to verify accuracy of inspection data Project-level Before repair project Experienced bridge engineer employed by consulting engineering firm Inspection to collect information for contract documents Acceptance After repair project Experienced bridge engineer employed by consulting engineering firm Inspection of work during and after contract TABLE 48 REQUIREMENTS FOR TESTS—NORWAY TABLE 49 TYPES OF BRIDGE INSPECTIONS—SOUTH AFRICA

36 Sweden Sweden has four levels of routine inspections: Regular, Superficial, General, and Major (Table 50). Regular inspec- tions are frequent, quick visits to bridges to detect significant new conditions. Such inspections are done by maintenance contractors, and may occur once a day or once a month. Su- perficial inspections are made once a year to verify that con- tract maintenance requirements are being met. Superficial inspections are done by maintenance contractors. General inspections are made every three years by trained inspectors from SRA staff or SRA consultants. General inspections check on defects discovered in a previous Major inspection. General inspections also examine electrical, hydraulic, or other bridge equipment. Major inspections are made every six years by trained inspectors from SRA staff or SRA con- sultants. Major inspections are complete examinations reporting all conditions and noting all defects in bridges, and include underwater inspection. Major inspections are the basis for specification of requirements for continuing maintenance. In addition, SRA performs Special inspections of known defects, suspected defects, and deterioration mechanisms, as needed. Special inspections will often involve testing meth- ods such as ultrasound, radiography, etc. United Kingdom The U.K. Highways Agency identified five types of bridge in- spection: Acceptance, Superficial, General, Principal, and Special (Table 51). Acceptance inspections are performed for new bridges, newly repaired bridges, and newly assigned responsibility; that is, at the start of a new maintenance con- tract. Superficial inspections are frequent visits to bridges made by the road maintenance contractor. Superficial inspections do not yield condition ratings. General inspec- tions are visual inspection of all parts of bridges. General in- spections are made every two years. No access equipment or lane closures are used. Principal inspections occur every six years and are thorough visual examinations of all parts of bridges, reporting all conditions and noting all defects. Inspection Type Interval Performed by Description Regular Frequent Maintenance contractor Quick visit to detect significant new conditions Superficial 12 months Maintenance contractor To verify that maintenance requirements are met General 3 years SRA staff or consultants Follow-up on damages detected at the last major inspection Visual inspection of components Major 6 years SRA staff or consultants Arms-length, visual inspection of all components. Includes underwater inspection Basis for recommendations for continuing maintenance Special As needed Consultants Further investigation of defect or deterioration mechanisms May involve testing methods Inspection Type Interval Performed by Description Acceptance N/A When responsibility for the structure changes hands; i.e., on completion of construction, when contracts for maintenance change Superficial Frequent Contractor The contractor staff is encouraged to be vigilant at all times and report anything needing urgent attention, such as impact damage to superstructure, bridge supports, flood damage, expansion joints, etc. General 2 years Contractor A visual inspection of all parts of the structure that can be inspected without special access equipment Principal 6 years Contractor Touching-distance visual inspection using any necessary access equipment Special As necessary Contractor To investigate some identified defect N/A = not applicable. TABLE 50 TYPES OF BRIDGE INSPECTIONS—SWEDEN TABLE 51 TYPES OF BRIDGE INSPECTIONS—UNITED KINGDOM

37 Special inspections, often involving material sampling or NDT applications, occur as needed. Inspections of the Highways Agency’s 10,000 bridges are done by consulting engineers. Inspections for approximately 100,000 bridges controlled by local road agencies are either done by local agency staff or by consultants. UNDERWATER INSPECTION—FOREIGN AGENCIES Intervals for underwater inspections are listed in (Table 52). Denmark The Road Directorate sets no fixed interval for inspection by divers. The regional bridge inspector selects the bridges and intervals for dive inspections. Inspections are done by con- sultants. Inspection by wading and probing, if appropriate, is performed during principal inspections. The underwater inspection affects the condition rating for the “underpassing” feature. Finland Underwater inspections by divers are done at 5-year intervals for Finnra. Scheduling is determined by the district bridge engineer. Seasons with high water or ice in streams are avoided. Finnra guidelines provide detailed lists of the com- ponents to inspect and the observations to make. Condition ratings of substructure components are affected by observa- tions from underwater inspections. France In France, dive inspections are sight and touch inspections of submerged components with probing at foundations for scour holes. Dive inspections are performed at 6-year intervals. Un- derwater inspections are separate from IQOA and detailed inspections. France defines both underwater inspections and underwater investigations. Investigations are thorough, arms- length examinations, and include measurements, sampling, or testing as needed. Germany In Germany, underwater inspections are done every 6 years as part of each Major test. If there is known damage, under- water inspections are performed during Minor tests as well. Dive inspections usually involve a diver with a video camera directed by a civil engineer at the surface. Inspections are by sight and by touch. South Africa Few South African bridges require underwater inspection by divers. There is no policy on interval or intensity of dive in- spections. No SANRAL bridges cross navigable waterways and there is no hazard resulting from vessel collision, other than small craft. Sweden In Sweden, underwater inspections employ divers at sub- merged foundations of bridges. Divers use sight and touch to inspect structural components and probe at foundations for scour holes. Video cameras are sometimes used. The channel profile may be measured at the discretion of the inspection team. Underwater inspections usually occur at 6-year intervals. United Kingdom For the Highways Agency, underwater inspections are usu- ally performed at 6-year intervals; however, area structures managers can set different intervals. The Highways Agency requires that all surfaces of a structure be inspected. This may be accomplished by divers or by other means. Area structure managers review and approve inspection plans submitted by maintenance contractors. Country Type Interval Notes Dive None When ordered by regional bridge inspectorDenmark Wade 6 years Performed during Principal inspection Finland Dive 5 years Schedule set by district bridge engineer Dive, Intensity 1 6 years Arms-length inspection Performed separately from other inspections France Dive, Intensity 2 None Includes measurements and material sampling Performed as needed Germany Dive 6 years Performed during Major test South Africa Dive None Few bridges require inspection by divers Dive 6 yearsSweden Channel profile None At discretion of inspection team United Kingdom Dive or wading 6 years Highways Agency Area Structures Manager reviews/approves contractor’s proposed method(s) for underwater inspections TABLE 52 UNDERWATER INSPECTION INTERVALS—FOREIGN AGENCIES

38 BRIDGE CONDITION DATA—FOREIGN AGENCIES Denmark The Road Directorate collects condition ratings for the fol- lowing 13 bridge components: 1. Entire structure 2. Wing walls 3. Slopes 4. Abutments 5. Intermediate supports 6. Bearings 7. Load-carrying superstructure 8. Waterproofing 9. Edge beams 10. Safety barrier/railings 11. Surfacing/permanent way 12. Expansion joints 13. Other components. Condition ratings (Table 53) are built up (literally summed) from three contributors: damage (3 pts), function (1 pt), and consequence (1 pt). The overall rating scale is 0 to 5, with “0” meaning no damage and “5” that the component can no longer function. The bridge file contains a record of each inventory in- spection, general inspection, and special inspection of the bridge. Routine inspections are not recorded in themselves, but a special inspection is always recorded, and these may be in response to a report from a routine inspection. Bridge components are identified in a hierarchical numbering system (Table 54) that allows inspectors to assign conditions and record observations about general regions of the bridge such as deck, superstructure, and substructure, and to make specific element-level repair recommendations. Finland Finnra practice assigns ratings to bridge defects in each of four categories: Weight (importance in the load path), condi- tion of the structural element (apart from this defect), ur- gency of the repair (rate of growth of defect), and damage class (severity of the defect) (Tables 55–57). Rating Description 0 Insignificant deterioration; little or no damage Component condition corresponds to that of a new component 1 Minor deterioration; damage with a very slow rate of development No repairs needed, as the condition more or less corresponds to that of a new component 2 Damage is at an early stage of development or there are a few fully developed defects Repairs should be carried out at any convenient time, as several years may elapse before the component no longer fulfils its function. 3 Damage has developed to such a degree and/or extent that it is likely that within a short time the component will no longer fulfill its function. Repair necessary within a year or two 4 The component is severely deteriorated, so that its capacity to fulfill its function has or will soon disappear. Repair necessary in the near future 5 The component has completely deteriorated and can no longer fulfill its function Immediate repair is necessary TABLE 53 COMPONENT RATING SCALE—DENMARK Level 1 Level 2 Level 3 Level 4 2100 Foundation and supports 2101 Pile 2102 End foundation 2103 Intermediate foundation 2200 Bearing structure 2201 Bearing 2300 Adjacent structure 2301 Slope 2000 Substructure 2400 ……………. 2401 …………. 3100 Load-bearing superstructure 3101 Deck slab 3102 Main beam …… ………… 3200 Road/railway 3201 Waterproofing 3202 Bridge surfacing ….. ………… 3300 Safety-barrier and railings 3301 Safety-barrier …. ………… 1000 Structure 3000 Superstructure 3400 ……………. 3401 ………… TABLE 54 HIERARCHICAL IDENTIFICATION OF BRIDGE COMPONENTS—DENMARK

France French practice reports condition ratings on a 1 to 3 scale. Ratings 2 and 3 are subdivided according to the urgency of maintenance. A special mention S is added to defects that may affect the safety of road users (Table 58). Germany In Germany, condition rating scales run from 0 (good) to 4 (very poor). Each bridge component is assigned three ratings; one each for structural damage, traffic safety, and bridge dura- bility (Tables 59–62). These ratings are combined automati- cally by SIB Bauwerke, the bridge management system, and a single rating for each bridge component is determined (15). Norway Norwegian practice reports condition ratings for bridge elements and identifies specific types of damage that are observed. Condition ratings are reported on a 1 to 4 scale, with 1 indicating good condition (Table 63). Condition ratings are provided for each of four consequences of element condition: strength (carrying capacity), traffic safety, maintenance costs, and aesthetics (Tables 64–67). The Norwegian inspection manual (17) lists approxi- mately 150 types of deterioration and damage in bridge com- ponents. Each type is identified by a three-digit code for use in inspection reports. For example, types of damage to con- crete elements are shown in Table 68. Similar lists, each specific to a construction material or to a type of bridge com- ponent, are provided in Norway’s manual. List headings are shown in Table 69. Sketches for location and extent of dam- age must employ a common set of symbols (Figure 1). Damage Class Damage Severity Points, 1—Mild 1 2—Moderate 2 3—Serious 4 4—Very serious 7 Condition Definition Urgency 1 Good condition 2 Good condition or minor defects; maintenance required Not urgent 2E Minor defect requires prompt maintenance Urgent 3 Damaged structure; repair needed Not urgent 3U Damage requires prompt repair Urgent NE Not evaluated Mention S Condition endangering the safety of users Urgent Assessment Description 0 Defect/damage has no effect on the strength of the element or structure. 1 Defect/damage affects the strength of the structural element, but does not affect the strength of the structure. Element and structure have adequate strength. Repairs can be carried out within the scope of regular maintenance. 2 Defect/damage affects the strength of the structural element and has little effect on the strength of the structure. Structure has adequate strength. Repairs are needed. 3 Defect/damage affects the strength of the structural element and the structure. Structure does not have adequate strength. Load posting is needed, but not currently in place. Required restrictions on the use are not in place or are ineffective. Repairs are needed. Load posting is needed. 4 Structural strength of the structural element is lost. Structure does not have adequate strength. Immediate restrictions on use are needed. Repair or rehabilitation is needed. TABLE 58 CONDITION RATINGS—FRANCE TABLE 57 FINNISH DAMAGE CLASS, D TABLE 59 CONDITION RATINGS FOR STRUCTURAL DAMAGE—GERMANY Condition Rating Condition Points, 0—New or like new 1 1—Good 2 2—Satisfactory 4 3—Poor 7 4—Very poor 11 Repair Class Repair Urgency Points, 11—Repair during the next two years 10 12—Repair during the next four years 5 13—Repair in the future 1 TABLE 56 FINNISH REPAIR URGENCY, U TABLE 55 FINNISH ELEMENT CONDITION, C 39

40 Assessment Description 0 Defect/damage has no effect on traffic safety. 1 Defect/damage has slight effect on traffic safety. Traffic safety is adequate. Repairs can be carried out within the scope of regular maintenance. 2 Defect/damage has slight effect on traffic safety. Traffic safety is adequate. Repairs must be carried out or warning signs must be put up. 3 Defect/damage affects traffic safety. Repairs must be carried out or warning sign must be put up at once. 4 Traffic safety is not adequate. Immediate restrictions on use are needed. Repair or rehabilitation is needed. Assessment Description 0 Defect/damage has no effect on the durability of the structural element or structure. 1 Defect/damage affects the durability of the structural element, but does not affect the durability of the structure. Affect on durability or damage of other elements is not expected. Repairs can be carried out within the scope of regular maintenance. 2 Defect/damage affects the durability of the structural element and may affect the durability of the structure. Affect on durability or damage of other elements may follow. Repairs are needed. 3 Defect/damage affects the durability of the structural element and the durability of the structure. Affect on durability or damage of other elements is expected. Repairs are needed. 4 Element and the structure are no longer durable. Durability of other elements is affected. Immediate repair or rehabilitation is needed TABLE 60 CONDITION RATINGS FOR TRAFFIC SAFETY—GERMANY TABLE 61 CONDITION RATINGS FOR DURABILITY—GERMANY Grade Description 1.0–1.4 Very good structural condition Continue normal maintenance 1.5–1.9 Good structural condition, but may have less long-term durability Continue normal maintenance 2.0–2.4 Satisfactory structural condition, but may have less long-term durability Continue normal maintenance and consider a plan for repair 2.5–2.9 Unsatisfactory structural condition Traffic safety may be affected Structure is not sufficiently durable Continue normal maintenance and plan for repair Restrictions on traffic use or load may be needed 3.0–3.4 Critical structural condition Traffic safety is affected Structure is not durable Immediate repair is needed Restrictions on traffic use or load are needed 3.5–4.0 Inadequate structural condition Traffic safety is not adequate Structure is not durable Immediate repair or rehabilitation is needed Restrictions on traffic use or load are needed TABLE 62 GERMANY: COMPUTED CONDITION RATINGS FOR COMPONENTS Rating Description 1 Minor damage or defects that might not require any remedial action within the next 10 years 2 Average or slight damage or defects that require remedial action within 4 to 10 years 3 Serious damage or defects that require remedial action within 1 to 3 years 4 Critical damage or defects that require remedial action within 0 to 1/2 year 9 Not inspected TABLE 63 NORWAY: CONDITION RATINGS

Rating Description 1T Minor damage/defect that might reduce traffic safety if not repaired within the next 10 years 2T Average damage/defect that may reduce traffic safety if not repaired within the next 3 to 10 years 3T Serious damage/defect that will reduce traffic safety if not repaired within 1 to 3 years 4T Critical damage that reduces traffic safety and requires immediate repair or repair within 6 months Report this damage to the Bridge Engineer immediately TABLE 65 NORWAY: CONDITION RATINGS FOR TRAFFIC SAFETY Rating Description 1M Minor damage/defect that might increase maintenance costs if not repaired within the next 10 years. 2M Average damage/defect that may increase maintenance cost or complexity if not repaired in the next 3 to 10 years. 3M Serious damage/defect that may increase maintenance cost or complexity if not repaired in the next 1 to 3 years. 4M Critical damage that will increase maintenance cost or complexity if not repaired immediately or within the next 6 months. Rating Description 1E Minor damage/defect that might affect the environment/aesthetics if not repaired within the next 10 years 2E Average damage/defect that might affect environment/aesthetics if not repaired within 3 to 10 years 3E Serious damage/defect that might affect environment/aesthetics if not repaired within 1 to 3 years 4E Critical damage that affects environment/aesthetics; needs immediate repair or repair within 6 months TABLE 66 NORWAY: CONDITION RATINGS FOR MAINTENANCE COSTS TABLE 67 NORWAY: CONDITION RATINGS FOR AESTHETICS Damage Code Description 201 Settlement of concrete element 202 Movement of concrete element 203 Deformation of concrete element 204 Cracks in concrete element 205 Rupture of concrete element 206 Damage to concrete surface treatment 207 Leakage/dampness of concrete element 208 Discoloration of concrete elements 209 Insufficient/damaged cover of concrete element 210 Weathering of concrete element 211 Honeycombing of concrete element 212 Delamination of concrete element 213 Spalling of concrete element 214 Corrosion of reinforcement 215 Wash out of concrete element 216 Inadequate cleaning of concrete element 217 Inadequate clearing-up/removal 218 Poor concrete quality 219 Scoring/undermining of concrete element 220 Missing part(s) of concrete element 290 Other damage to concrete element Damage Code Description 100 Elements in ground 200 Concrete elements 300 Steel, aluminum, and iron elements 400 Stone/masonry elements 500 Timber elements 600 Deck surfacing 700 Bearings and joints 800 Drainage, approaches, and accessories TABLE 68 NORWAY: CODES FOR DAMAGE TO CONCRETE ELEMENTS TABLE 69 NORWAY: SERIES FOR DAMAGE TYPES Rating Description 1C Minor damage/defect that might reduce strength if not repaired within the next 10 years. 2C Average damage/defect that may reduce strength if not repaired within the next 3 to 10 years. 3C Serious damage/defect that will reduce strength if not repaired within 1 to 3 years. 4C Critical damage that reduces strength and requires immediate repair or repair within 6 months. Report this damage to the Bridge Engineer immediately. TABLE 64 NORWAY: CONDITION RATINGS FOR STRENGTH

42 Casting joint Delamination, spalling Porous or bad quality concrete Area of measurement Cracks > 2,0 mm Cracks Cracks >0,2 mm, <2,0 mm Cracking Visibly corroding reinforcement FIGURE 1 Norwegian graphic symbols for damage. Category Description D—Degree of defect Severity of defect E—Extent of defect Prevalence of defect within the bridge element R—Relevancy of defect Impact of the defect on structural integrity and/or user safety U—Urgency of defect Recommended time for repair Rating Degree Extent Relevancy Urgency 0 None Monitor only 1 Minor Local Minimum Routine 2 Fair >Local Moderate <5 year 3 Poor <General Major <2 year 4 Severe General Critical ASAP TABLE 71 SOUTH AFRICA: DEFECT RATING VALUES TABLE 70 SOUTH AFRICA: DEFECT CATEGORIES South Africa SANRAL records defects in bridge components with ratings for Degree, Extent, Relevancy, and Urgency. This system employs integer ratings in all four categories (Table 70). Rat- ings range from 0 (no defect) to 4 (critical defect) (Table 71). Sweden The SRA collects ratings and other data on conditions of bridge components during General, Major, and Special inspections. A Regular inspection may yield a report of dam- age that is followed up by a Special inspection. The condition data, strictly, are from the Special inspection. Superficial in- spections may record condition data as indicators of ade- quacy of work by the maintenance contractor. Defects in bridges are reported in terms of physical, func- tional, and economic conditions. Physical condition is reported as a measurement of an appropriate physical quantity. The quan- tity and the method of its measurement are fitted to the type of damage, structural element, material, and other considerations (e.g., mode of action of element). Functional condition is re- ported on a 0 to 3 rating scale, with 3 being the worst condition (Table 72). Functional condition is related to the time until the defect is expected to impair the service of the bridge. Economic condition is expressed as cost. Economic con- dition is computed as defect quantity times average unit cost for repair. This is not an estimate of actual project costs, because project scope may differ from defect quantity. However, greater values of economic condition correctly in- dicate more severe and more extensive defects. United Kingdom During Principal inspections, defect severity is reported on a 1 to 5 scale, and defect extent on an “A” to “E” scale. These condition ratings are used in Structures Management Infor- mation System to generate the performance indicator for visual condition. ACCESS FOR INSPECTIONS— FOREIGN AGENCIES Foreign road agencies reported on the use of traffic lane clo- sures, lifts or climbing for acceptance inspections, principal inspections, and special inspections; that is, at longer inspec- tion intervals. These access methods are not used during rou- tine inspections at shorter intervals (Tables 73–75). Rating Physical Condition Functional Condition 3 Repair needed now Service impaired now 2 Repair within 3 years Service impaired within 3 years 1 Repair within 10 years Service impaired within 10 years 0 Repair beyond 10 years Service greater than 10 years TABLE 72 SWEDEN: CONDITION RATINGS

43 Country Inspection Type Lifts, Other Equipment Special Nearly always uses liftsDenmark Principal, Special Might use boats General Rarely General, Large bridge Often Finland Basic, Special Often Routine, Annual, IQOA NoFrance Detailed Yes, France has a special snooper for great arches and piers. Superficial, Minor, NoGermany Major Yes General NoNorway All other types Inspectors must be at arms length to component Principal If neededSouth Africa Other types Seldom used General, Major, Special If neededSweden Routine, Superficial No Acceptance, Principal, Special YesUnited Kingdom General No TABLE 74 USE OF LIFTS AND OTHER EQUIPMENT FOR INSPECTION ACCESS—FOREIGN AGENCIES Country Inspection Type Lane Closures Routine, Principal Very rareDenmark Special Nearly always General Rarely, except if inspection lift is usedFinland Basic, Special Often Routine, Annual, IQOA NoFrance Detailed Yes Superficial, Minor, NoGermany Major Yes, if needed General NoNorway All other types Inspectors must be at arms length to component Principal Yes, if needed Acceptance Yes, to test water tightness of joints South Africa Other types Seldom used General, Major, Special If neededSweden Routine, Superficial No Acceptance, Special Yes, but structure may not be open at time of acceptance inspection. For special inspection, closure may be used during installation of instruments for monitoring. United Kingdom All others No TABLE 73 USE OF LANE CLOSURES FOR INSPECTIONS—FOREIGN AGENCIES Country Inspection Type Climbing Denmark Special Large structures and by special personnel only Finland All Climbing is not used. Access is by lifts, if necessary. Superficial, minor NoGermany Major Yes, if needed General NoNorway All other types Inspectors must be at arms length to component Principal If neededSouth Africa Other types Seldom used General, major, special If needed, and performed by trained personnelSweden Routine, superficial No United Kingdom Special Yes, abseilers (rappelling) TABLE 75 USE OF CLIMBING, LADDERS, AND OTHER METHODS FOR BRIDGE INSPECTION— FOREIGN AGENCIES

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TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 375: Bridge Inspection Practices examines bridge inspection practices in the United States and selected foreign countries. The report explores inspection personnel (staff titles and functions, qualifications, training and certification, inspection teams, and the assignment of teams to bridges), inspection types (focus, methods, and frequency), and inspection quality control and quality assurance. The report also reviews the uses agencies make of information gathered from bridge inspections, what triggers repairs, and plans for future development of inspection programs.

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