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30 INSPECTION TYPES--FOREIGN ROAD AGENCIES Detached objects; for example, fragments of concrete, railing segments, and goods that have fallen off lorries; Denmark Function of drainage systems; Conditions of road surface; and The Danish Road Directorate identifies eight types of bridge Winter conditions; accumulation of ice and snow. inspections (Table 42). · Inventory inspections are made for new bridges, after Daily inspections are not recorded in the bridge database. major projects on bridges, and in general after each sig- nificant construction or repair event in the service life of · Routine inspections are done once a year by the mainte- a bridge. nance foreman or the bridge engineer for the road man- · Daily inspections are made by road maintenance crews. agement authority. The inspector must stop and view the Each day, the highway road patrol performs a drive-by bridge from the deck and from below. The inspector ver- inspection of all national roads, noting distress in ifies that recommended cleaning and routine mainte- bridges, pavements, and all other road facilities. Crews nance have been done and makes further recommenda- observe each bridge in all weather conditions and tions for cleaning and maintenance for the next year. develop a thorough familiarity with each structure and Maintenance work that is not complicated and of modest its basic systems. Daily inspections note: cost (around $20,000 U.S. maximum) is programmed Failure of load-bearing components; through Danbro, the Danish bridge management system, Impact damage; and done by maintenance contractors. Maintenance con- Washing away of slopes, shoulders, etc.; tractors are supervised by the Directorate's regional Vandalism on slope facings, railings, traffic signals, bridge inspector. Routine inspection notes: lights, etc.; Stoppage of drainage systems; TABLE 42 TYPES OF BRIDGE INSPECTIONS--DENMARK Inspection Type Description Interval Inspector Inventory Collect bridge data and baseline At new construction, and Bridge inspector conditions after every major repair project Dailya Cursory examination noting Daily Road failure, damage, debris, etc. maintenance crewb Routine-- Planning and checking routine Annually Consultant Extended cleaning and maintenance bridge inspector Inspectors stop and view the structure from the top and bottom Damage, if any, is noted. Reports from Reports of: In response to user report Users impact damage vandalism debris on bridge or road erosion damage Principal Thorough and systematic visual 6 years or lessc Directorate inspection of all the components bridge inspector of the bridge Special Collection of more detailed In response to Consultant information for decisions on recommendation from bridge inspector maintenance actions routine inspection Economic Preparation for major repair In advance of project Consultant Special project for a bridge selection and development bridge inspector Inspection Development and comparison of remedial strategies Technical Damage investigations In response to extreme event, Consultant Special Special investigations or suspect capacity bridge inspector Inspection Load-carrying capacity evaluations a Not a formal part of the Directorate bridge inspection program. b Specially 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.
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31 Grit and dirt, especially along edge-beams, gutters, the formation and updating of bridge deterioration low points, expansion joints, etc.; models. Basic inspections are performed by degreed Unwanted vegetation; engineers who are certified bridge inspectors. Erosion on slopes, washing away of foundations, · Special inspections collect complete, detailed informa- hindrances, and deposits in watercourses; tion in preparation for repair projects. Special inspec- Settlements at abutments and around manholes; and tions are usually done by certified inspectors who are A need for preventive maintenance (e.g., surface pro- degreed engineers and have experience with the testing tection of concrete). methods that may be needed at particular structures. · Reports from highway users can require special visits to · Underwater (dive) inspections are done by certified in- bridges. Often these reports deal with impact damage, spectors with special training. Bridge components are vandalism, debris on the road, and erosion damage. inspected both visually and by touch. · Principal inspections are thorough visual inspections of · Intensified monitoring, a kind of interim inspection, is all components. The inspector assigns condition ratings to performed on selected components and may be done by all components. Principal inspections are usually per- bridge inspectors, engineers, or road foremen depend- formed at 6-year intervals, but may be undertaken at ing on the nature of the monitoring program. 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 For long-span bridges in good condition, general inspec- Principal inspection and may recommend additional spe- tions are performed at 8-year intervals. The inspection of a cial inspections. The interval to the next inspection de- long-span bridge is a complex effort that requires lane clo- pends on the bridge age, average daily traffic, location, sures and lift equipment. Long-span bridges usually have existing conditions, and special features. Recommenda- high traffic volume. Inspections are intentionally more tions for maintenance and repair are made, with the in- intense at large bridges, with the increased scrutiny permit- spector estimating the cost for each recommendation and ting the longer inspection interval. indicating when the recommendation should be com- pleted (within 1 year, 2 years, or as many as 11 years into For most bridges, inspection intervals are determined by the future). two factors. One is the bridge; inspection intervals are con- · Special inspections collect more detailed information sistent with the condition of each bridge. The other is logis- about specific conditions at bridges. tics; bridges in remote areas are inspected when personnel · Economic special inspections provide information are on hand; therefore, inspection intervals may be somewhat needed for selection of repair strategy and development longer or shorter than intended. of plans. · Technical special inspections are detailed investiga- tions of damage seeking causes of damage and evaluat- France ing the effect of damage on load capacity. France has four types of routine inspections: routine visit, annual inspection, IQOA (Image de la qualité des Ouvrages Finland d'Art: Image of the Quality of Bridges, Walls, and Tunnels) Finland defines seven types of routine bridge inspection (see evaluation, and detailed inspection (Table 44). Routine Table 43). visits are made by road agents during their patrols. Annual inspections are cursory examinations intended to discover · Acceptance inspections are done to add or modify bridge new, significant defects in structures, and to program inventory data (the Finnish term is "registry data"). Ac- routine maintenance. IQOA evaluations occur every three ceptance inspections occur for newly constructed years and are more complete visual examinations of struc- bridges and after major repair or modification projects. tures to establish the condition of bridges in IQOA classes. · Annual inspections are performed by road maintenance Detailed inspections occur at intervals ranging from 3 to 9 foremen, or consultants hired by road foremen, and years, depending on bridge condition, and are thorough seek conditions that are a threat to safety. visual examinations of bridges noting all defects. The de- · General inspections are thorough visual inspections tailed inspection is a "blank slate" examination. The annual performed every 5 years for most bridges, and every 8 inspection, in contrast, is a check of defects known to exist years for large bridges. All bridge components are at the structure. assigned condition ratings, and inspection data are entered in the bridge registry. General inspections are Annual inspections and IQOA inspections often require done by certified bridge inspectors. about one-half day of work for the inspection team. Detailed · Basic inspections are similar to General inspections, but inspections require additional time and usually require are performed on a select population of 125 bridges access using lane closures, lift equipment, etc. The detailed called reference bridges. Data from basic inspections inspection is a hands-on inspection. This is mandatory; the and the accompanying materials tests are the basis of inspector must be able to touch each component.
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32 TABLE 43 TYPES OF BRIDGE INSPECTIONS--FINLAND Inspection Type Description Interval Inspector Acceptance Collect data for bridge registry After construction or District bridge engineer repair work Inspection of all components at Bridge engineer and arms length designer First general inspection of a large bridge Annual Cursory inspection for safety 1 year Road foreman or maintenance consultant General Inspection of all components at 4 to 8 years (usually 5 Certified bridge arms-length years) inspector Results are stored in the Bridge Registry by the inspectors themselves. Inspection of all components at Large waterway bridges Certified inspector with arms-length 8 years engineering degree NDT methods are used when necessary Results are stored in the Bridge Registry by the inspectors themselves. Basic For reference bridge group 5 years Certified inspector with engineering degree Inspection of all components Includes material sampling and testing to improve deterioration models Special Methods vary with needs of For planning and Certified inspector with project development of repair engineering degree projects Machinery of movable bridges; 1 year Specialist includes annual maintenance Suspension cables, stay cables 15 years Certified bridge inspection, specialist in cables Underwater Inspection by diving; visual and 5 years Certified inspectors with touch inspection of components special training Intensified More frequent inspection Due to poor or weakened Monitoring condition Germany Minor tests are done three years after each major test. Minor tests use findings of the previous major test and focus Germany performs bridge inspections at two levels called on known damage and defects. Access equipment is not used Major Test and Minor Test (15) (Table 45). Major tests are in a Minor test, but the level of effort is expanded as necessary arms-length (DIN wording is "touching-distance") inspec- for the conditions that are observed. Tests of electrical and me- tions of all elements with access to all parts. This entails chanical equipment, such as ventilation systems, are required opening access doors and covers, using lift equipment, per- by statute. forming underwater inspection, and inspecting the riverbed. Lane closures are used, if necessary, but use is limited by the All highway structures are visited twice a year for safety. large traffic volume on most federal roads. Major tests are Viewing is from the ground level as well as the traffic level. performed at acceptance of construction, near the end of the Germany performs ad hoc inspections after significant events guarantee period, and every six years during service life. such as storms or floods.
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33 TABLE 44 TYPES OF BRIDGE INSPECTIONS--FRANCE Inspection Type Interval Performed by Description Routine Visit Frequent Road maintenance agents Drive-by inspection employed by DDE Annual 1 year Road maintenance agents Cursory examination during visit to employed by DDE bridge IQOA 3 years Inspection agent sometimes Visual verification of conditions with certified inspector focusing on known defects Detailed 9 years Certified inspector Robust bridges. Arms-length visual examination of all components and noting all defects 6 years Certified inspector Normal bridges. Arms-length visual examination of all components and noting all defects 3 years Certified inspector Ill bridges. Arms-length visual examination of all components and noting all defects 1 year Certified inspector Very ill bridges. Arms-length visual examination of all components and noting all defects Underwater 6 years Certified inspector Diver making arms-length touch and visual inspection DDE = Direction Départementale de líEq uipment. The names of inspection types are used a bit differently in the · Installation of fixed ladders; German preservation and maintenance guide (15) (Table 46). · Lighting, both exterior and interior; and · Room for jacking points at abutments. 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 Norway designers to consider: The Norwegian Public Roads Administration (17) identifies three classes and seven types of inspection (Table 47). · Visibility of parts; · Internal clearances in boxes; · Acceptance inspections are performed for new con- · Interior ventilation; struction and after major repair projects. TABLE 45 TYPES OF BRIDGE INSPECTIONS--GERMANY Inspection Type Description Interval Performed by Major Test Arms-length inspection of all components; 6 years Bridge inspector uses access equipment and includes underwater inspection 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 3 years after Major test Bridge inspector damage and defects Superficial Cursory inspection for safety 3 months Road maintenance crew Ad Hoc After significant events, such as storms, N/A Depends on floods, etc.; also for known, severe situation damage. Systems Inspection of electrical or mechanical As required by systems regulation N/A = not applicable.
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34 TABLE 46 INSPECTION DESIGNATIONS--GERMANY 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 S1S9 Special inspections (inspection owing to particular reasons) Warranty inspections are performed near the end of part of quick surveys conducted after accidents, floods, the warranty period for construction or repairs. cyclones, or other extreme events. · Routine General inspections every 1 or 2 years, and Principal inspections are conducted every 5 to 6 years by Major inspections every 5 to 10 years. Structural inspectors who are experienced in bridge design, maintenance, cables are inspected every 5 years. or rehabilitation. Principal inspections are thorough examina- · Additional Special inspections for known damage or tions of bridges that record all defects. A principal inspection after extreme events are performed as needed. produces a full inspection report with photographs. The 5-year interval for principal inspections matches SANRAL's 5-year Norway specifies the field measurements and materials tests programming cycle for bridge repairs. that are part of each type of inspection (Table 48). General inspections require few measurements and no materials testing. Verification inspections are part of SANRAL's QA pro- Major inspections require many measurements and tests. gram. Each year some bridges are selected and their condi- tions are verified by a senior bridge inspector. South Africa Two event-related inspections pertain to repair projects. (1) The project-level inspection is a directed examination of South African practice includes three types of routine inspec- a bridge to collect data needed for the preparation of contract tions: Monitoring, Principal, and Verification (Table 49). Mon- documents for a repair project; and (2) an acceptance inspec- itoring inspections are performed by maintenance personnel tion is made after repairs are complete. and occur at frequent but irregular intervals. Maintenance per- sonnel report problems, if any, but do not otherwise report that Condition data from principal inspections are stored in the specific bridges have been visited. Monitoring inspections are bridge database. Monitoring inspections do not produce con- part of routine maintenance surveys for road sections and also dition ratings. TABLE 47 TYPES OF BRIDGE INSPECTIONS--NORWAY Class Type Description First Acceptance Performed for new construction and after major repair projects inspection Note deficiencies and damage Identify sources of deterioration that may be significant to maintenance Warranty Performed near the end of the warranty period inspection 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 Routine General Check for any serious damage affecting the load capacity, traffic safety, inspection future maintenance, or environment/aesthetics Major Inspection of all components inspection Determine needs for maintenance or repair Estimate costs of maintenance or repair Measurements and material sampling as needed Major Inspection of cables, hangers, clamps and anchorage points inspection-- Verify adequacy and function of cable systems Cables Determine maintenance needs and costs Major Dive inspection inspection-- Inspect submerged components Underwater Inspect the river bed Determine maintenance needs and costs Additional Special Diverse purposes: inspection investigation of known damage development of repair/rehabilitation projects checking after extreme events checking after problems at bridges of similar type
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35 TABLE 48 REQUIREMENTS FOR TESTS--NORWAY Major Major Acceptance Warranty General Major Inspection Inspection Special Inspection Inspection Inspection Inspection Cable Underwater Inspection Measurements Bearing elevations X X X X Horizontal distances/displacement X X X X X Thickness of wearing surfaces X X X X Track wear 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 X Chloride content X X X X Corrosion investigation (ECP) X Structural analysis X Inspection of bracing cables X Cutting open the concrete to assess X corrosion level 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 X thickness 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 X X (concrete) Adhesive bonding between surface X X coating and concrete Thickness of surface coating (steel) X X Adhesive bonding between surface X X coating and steel Condition of surface coating (wood) X X TABLE 49 TYPES OF BRIDGE INSPECTIONS--SOUTH AFRICA Inspection Type Interval Performed by Description Monitoring At least once each year, Maintenance personnel Quick look for new defects usually more and status of known frequently defects Principal 5 years Inspectors experienced in bridge Full report with design or maintenance 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 Inspection to collect employed by consulting information for contract engineering firm documents Acceptance After repair project Experienced bridge engineer Inspection of work during employed by consulting and after contract engineering firm
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36 TABLE 50 TYPES OF BRIDGE INSPECTIONS--SWEDEN Inspection Type Interval Performed by Description Regular Frequent Maintenance Quick visit to detect significant new conditions contractor Superficial 12 months Maintenance To verify that maintenance requirements are met contractor General 3 years SRA staff or Follow-up on damages detected at the last major consultants inspection Visual inspection of components Major 6 years SRA staff or Arms-length, visual inspection of all components. consultants Includes underwater inspection Basis for recommendations for continuing maintenance Special As needed Consultants Further investigation of defect or deterioration mechanisms May involve testing methods Sweden In addition, SRA performs Special inspections of known defects, suspected defects, and deterioration mechanisms, as Sweden has four levels of routine inspections: Regular, needed. Special inspections will often involve testing meth- Superficial, General, and Major (Table 50). Regular inspec- ods such as ultrasound, radiography, etc. 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- United Kingdom perficial inspections are made once a year to verify that con- tract maintenance requirements are being met. Superficial The U.K. Highways Agency identified five types of bridge in- inspections are done by maintenance contractors. General spection: Acceptance, Superficial, General, Principal, and inspections are made every three years by trained inspectors Special (Table 51). Acceptance inspections are performed for from SRA staff or SRA consultants. General inspections new bridges, newly repaired bridges, and newly assigned check on defects discovered in a previous Major inspection. responsibility; that is, at the start of a new maintenance con- General inspections also examine electrical, hydraulic, or tract. Superficial inspections are frequent visits to bridges other bridge equipment. Major inspections are made every made by the road maintenance contractor. Superficial six years by trained inspectors from SRA staff or SRA con- inspections do not yield condition ratings. General inspec- sultants. Major inspections are complete examinations tions are visual inspection of all parts of bridges. General in- reporting all conditions and noting all defects in bridges, and spections are made every two years. No access equipment or include underwater inspection. Major inspections are lane closures are used. Principal inspections occur every six the basis for specification of requirements for continuing years and are thorough visual examinations of all parts maintenance. of bridges, reporting all conditions and noting all defects. TABLE 51 TYPES OF BRIDGE INSPECTIONS--UNITED KINGDOM Inspection Performed Type Interval 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 Contractor To investigate some identified defect necessary N/A = not applicable.