Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 22
22 CHAPTER 2 National Bridge Maintenance Database The National Bridge Maintenance Database (NBMD) is a 1. Structure, collection of self-contained sets of data on bridge inventory, 2. Operation, conditions, and maintenance work. Each dataset is established 3. Dates, for one state DOT and for a fixed reporting period, usually one 4. Resources, and year. Data are collected from records of the U.S. NBI, from 5. Outcomes. Pontis bridge databases of state DOTs, from DOT mainte- nance management systems, from maintenance work report- The Structure. NBMD stores selected fields from NBI ing systems and from contract reporting systems. NBMD offers records and Pontis bridge databases. These include NBI and a uniform, consistent format and structure for data on bridge Pontis condition data together with data on structure type, maintenance work, on the context of bridge maintenance work, route, milepost, custodian, structural size, age, construction and on the outcomes of bridge maintenance work. materials, and administrative authority. The NBMD data system is a set of standard data tables, stan- dard headings for data fields, standard keywords for indexing The Operation. Maintenance work is identified using fields, and standard methods for the creation of unique identi- NBMD standard keywords for components and operations. fiers for bridges, bridge elements, maintenance actions and maintenance resources. NBMD is instantiated as a set of plain The Dates. The date(s) of completion of the maintenance text data files, and a set of XML documents each supported by event are recorded. an XML schema. Three concepts are applied to NBMD design. First, bridge The Resources. Resources include usage of labor, materi- maintenance data are collected into self-contained datasets als, and equipment for DOT work, or pay items and quanti- that bundle all related maintenance, condition, and inventory ties for contract maintenance. Specific repair products and data. Second, data are presented in plain language keywords manufacturers can be stored. Resource data are used to com- so that information is easily understood without recourse to pute total costs and unit costs for actions. coding guides or lookup tables. Data headings, too, are pre- sented in plain language. Third, NBMD datasets are stackable. The Outcomes. Outcomes include maintenance produc- Unique IDs for bridges, elements, actions, and resources are tion and changes to conditions. Production may be expressed established for each dataset and remain unique when datasets in units for the maintenance action and as the quantity of are merged. Merging allows for aggregations of large num- bridge element that is improved. Conditions are new values of bers of data records when data analysis and statistical evalua- bridge condition ratings achieved as a result of this mainte- tions require it. nance event. A Database for Bridge Maintenance Standard Data for Highway NBMD is an archive of maintenance events. An event is the Bridge Maintenance execution of one maintenance operation at one bridge at one Standard Bridge Components time. Each record in the database is a single event, and each record contains complete information on the work performed. NBMD uses 14 standard bridge components (Table 9). Five The data include the following: components are named in the NBIS (Deck, Superstructure,
OCR for page 23
23 Table 9. Standard bridge components. Component Description Approaches/ Approach slab and pavement, slopes, slope protection (other than channel Embankments banks), embankments. Bearings Bearing devices, both fixed and expansion. All bridges on the state's list, also a catch-all component for maintenance work Bridge not reported under other components. Channel Watercourse, flow restrictors/deflectors, banks, and bank protection. Culvert All types and sizes of culverts maintained by structures maintenance program. Deck The structural deck, wearing surface, waterproofing membrane, if any. Drains Scuppers, grates, pipes, outlets, features for over-the-edge drainage. All joints in the deck, all maintainable (sealable) joints in superstructure and Joints substructure components. Mechanical Electrical or mechanical systems on bridges, includes all mechanical and electrical /Electrical equipment for movable spans, all gates, lights and delineators for traffic. Movable The operable parts and systems of a movable bridge. Includes deck and span superstructure of movable span. nonBridge Other structural assets. All deck accessories for directing/restricting vehicles and pedestrians. All Rails/Walks sidewalks and medians. Substructure Piers, abutments, and their foundations. Wing walls. Superstructure Stringers, floorbeams, girders, truss members, arch members, etc. Substructure, Channel, Culvert). Seven more components are Standard Maintenance Operations used by many DOTs as objects of maintenance actions (Joints, Drains, Railings, Bearings, Approaches, Movable Bridge, Elec- NBMD uses eight standard maintenance operations: trical & Mechanical Systems). A twelfth component, Bridge, Clean, Reset, Coat, Repair, Replace, Modify, Emergency, and is used when actions are applied to an entire structure, or a nonMaintenance (Table 10). Note that a Replace operation specific component is not reported. The thirteenth compo- refers to the replacement of a part or portion of the bridge. nent, nonBridge, is used for other assets. Complete replacement of a bridge is not maintenance. In a Table 10. Standard maintenance operations. Operation Description Sweeping, washing, debris removal, graffiti removal, clearing scuppers, clean-out Clean/clear drain lines. Renew consumable elements such as lights, removable joint seals; Tighten bolts or Reset rods, Lubricate bearings or other moving parts; Minor re-alignment of railings, repositioning of bearings. All surface applications of paint, waterproofing, galvanic coatings, chemical Coat preservatives, crack sealing materials. Repair Restoring damaged or deteriorated elements. Patching, welding, reinforcing, etc. Replace In-kind replacement of damaged or deteriorated elements. Repair or replacement actions that yield changes to elements. These may be improvements to function as when drains are extended, changes in function as when relief joints are installed in rigid pavements, changes to vulnerability as by seismic Modify retrofit, changes to strength by post-tensioning, jacketing, installation of scab plates, changes to clearances as by re-positioning of bracing in truss portals, or installation of a system for corrosion protection when none was present before. All repairs, replacements, and modifications completed as an immediate response to Emergency a sudden condition or event. nonMaintenance Operations, inspections.
OCR for page 24
24 similar way, Modify operations include minor modifications, Improvements may include: greater clearances, greater resis- and exclude larger projects such as bridge rehabilitation. tance to fatigue, greater safety for traffic, greater resistance to Maintenance activities are generic methods for maintenance high water flow, etc. Modify operations may be in response to operations. Activities are modifiers to operations, providing obsolete features, as when railings are upgraded, or in response more specific reports of maintenance work. Each operation has to damage or deterioration. its own set of activities. Actions are reported in a hierarchy of fields such as the following: Maintenance Activities Component Operation Activity Mode Activities are descriptive keywords for NBMD bridge main- tenance operations. Examples of Activities for maintenance NBMD employs standard keywords for components and operations are presented in the following sections. operations and allows descriptive keywords for activities and modes. Actions must be reported by component, should be Activities for Clean/Clear Operations. The Clean/Clear reported by operation, may be reported by activity, and might operation includes washing of structures, and removal of detri- be reported by mode. This hierarchy admits both general tus, drift, and vegetation. Activities for Clean/Clear operations are described in Table 11. (component only) and detailed (all four descriptors) report- ing of maintenance actions. Activities for Reset Operations. The Reset operation provides expected maintenance for consumable parts or parts Notes on Maintenance Operations needing periodic lubrication or adjustment. Activities for reset operations are described in Table 12. Reset versus Repair/Replace. The replacement of con- sumable parts is a Reset operation. Parts such as light bulbs, Activities for Coat/Paint Operations. The Coat/Paint fan belts, gaskets, and rubber joint elements are replaced as operation includes all application, maintenance and renewal needed or on a set schedule. Repairs are made in response to of surface-applied sealers, paints and chemical treatments. deterioration or damage and entail parts that are not con- Activities for Coat/Paint operations are described in Table 13. sumable. The designation of these activities as Repair or Replace correctly identifies the significance of the operation Activities for Repair Operations. The Repair operation within the maintenance program, and correlates with costs restores original condition or functionality of bridge compo- since consumable elements are designed for replacement and nents after deterioration or damage. Repair does not include other parts might not be. substantial replacement of components and does not include improvements to components beyond their original capacity Modify versus Repair/Replace. Modify operations are or function. Activities for repair operations are described in repairs or replacements that change (usually improve) bridges. Table 14. Table 11. Activities for clean/clear operations. Activity Description Wash The use of water at moderate pressure to clean bridge components. Washing of selected portions of components, usually those portions exposed to salt Zone water, salt spray, or standing water. These can include parapets facing traffic, gutters Wash in decks, and areas below open joints. Any selective washing of portions of structures. Sweep Dry removal of sand, grit, or other minor detritus on bridge components. The use of water at higher flow rate and/or pressure to clear more substantial size or Flush amounts of detritus on bridge components. Unclog Maintenance of scuppers, troughs, pipes, and other drainage elements. Methods and entail opening grates and cleanouts, removal of waste material, flushing as needed and Cleanouts reassembly of parts. Graffiti Removal or covering (masking) of unauthorized markings on bridges. Trimming and/or removal of brush, trees, etc., on slopes, approach embankments, Vegetation channel banks and within channels. Debris & Removal of (loose) material on substructures, at foundations, on channel banks and Drift within channels. This activity does not include channel dredging.
OCR for page 25
25 Table 12. Activities for reset operations. Activity Description Consumables Replacing light bulbs, rubber joint elements, pavement reflectors, etc. Checking and tightening of bolts, anchors, rods and other threaded parts. Tighten also Tighten includes replacement of missing fasteners in otherwise complete connections. Caulk Removal and replacement of caulk in railings, fixed joints and construction joints. Inspection and lubrication of bearings, expansion joints, railing joints and other moving Lubricate or sliding parts. Inspection and re-centering or re-alignment of bearings, joints, and other parts needing Reposition periodic adjustment. Gates and Inspection and servicing of traffic control systems, especially for movable bridges. Signals Inspection and servicing of mechanical parts of motion equipment for movable spans. Mechanical Mechanical Equipment includes consumables (filters, belts, etc), lubrication, and Equipment adjustment of machinery. Inspection and servicing of electrical parts of motion equipment for movable spans. Electrical Electrical Equipment includes consumables (fuses, switches), and adjustment of Equipment equipment. Table 13. Activities for coat/paint operations. Activity Description Paint Application of paint on bridge components, usually to an entire component. Application of paint on selected areas of components that may include: areas of Spot deteriorated paint, areas of special exposure (splash zones), damaged areas (as by Paint collision), etc. Seal Application of water-repelling or other surface treatments, usually to concrete or Surface asphalt surfaces. Use of epoxy, high-weight methyl-methacrylate or other pourable materials to fill Seal existing cracks. Usually applied to concrete surfaces, but can be crack sealing in Cracks asphalt surfaces and crack sealing in timber elements. Chemical Surface application of preservatives for timber components. Surface application of Treatments herbicides or pesticides on slopes as part of bridge maintenance. Surface Preparation of surfaces for coating or painting if separate tracking of preparation cost Preparation is desired. Otherwise, surface preparation is part of a coating or painting action. Table 14. Activities for repair operations. Activity Description Repairs to concrete components, concrete surfaces, or asphalt surfaces by filling Patch with cementitious or bituminous material Work to restore lost or weakened anchors for railings, joints, bearings, or other Re-attach/ Re-anchor components. Straighten For metal components, the use of bending or heat to restore proper shape. For pavements or substructures, the use of jacking and filling to mitigate tilting Jack/Align or settlement. Application of welds, scab plates, concrete jackets, cables, post-tensioning, etc., Reinforce/Strengthen to restore strength to weakened structural components. Earth moving activities to repair shifted or scoured slopes and banks, or to re- Dredge/Grade establish channel depth and profile.
OCR for page 26
26 Table 15. Activities for replace operations. Activity Description Replacement of an individual unit of a component made up of a collection of units, Individual such as replacement of individual bearings, individual joints, individual beams, individual piers. Replacement of a portion of a continuous component, such as a bridge deck, that is not Section a collection of similar units. Replacement of an entire component. Complete replacement of a collection of Complete elements. Complete replacement of a continuous component. Span Complete replacement of a component within one span of a multispan bridge. Activities for Replace Operations. The Replace operation Activities for Emergency Operations. Emergency activi- provides in-kind replacement of bridge components in whole ties are performed in response to extreme events and/or sudden or in part. Activities for Replace operations are described in damage to structures. Activities for Emergency operations are Table 15. described in Table 17. Activities for Modify Operations. The Modify operation provides improvements to components. Improvements may Operations, Activities, and Bridge Components mitigate observed problems in performance of components, Activities, more so than operations, may target specific com- may reduce vulnerability of components, or may deliver com- ponents or construction materials. Frequent combinations of pliance with higher or newer standards, especially where stan- activities with bridge components are discussed in this section. dards can be met within a maintenance project rather than a rehabilitation project. Activities for Modify operations are Clean/Clear Operations. Among the activities for Clean/ described in Table 16. Clear operations: Wash applies to structural elements, but not Table 16. Activities for modify operations. Activity Description Modifications to clearances including internal clearances of thru-trusses and thru- Geometry arches. Addition of protection system that is new to the component, including corrosion Protection protection, fenders, channel modifications. Modifications that reduce vulnerability to fatigue, seismic loads, sudden fracture, Vulnerability etc. Modifications that increase load rating of bridges, flood/flow capacity of channels, Strength/Capacity flow capacity of drains, motion capacity of expansion joints or bearings, etc. Modifications that alter load paths or expansion regimes. These may be: helper Function bents, conversion to integral abutments, relief joints in approach pavements, etc. Modifications that provide a newer device, such as a joint, bearing, or railing in Assembly place of an older, obsolete device. Table 17. Activities for emergency operations. Activity Description Post Investigations and repairs leading to load restrictions on structures. Installation of temporary supports for decks or superstructures. Construction of Shore "diapers" to catch loose materials. Closure, Activities to exclude traffic from some portion of a structure, such as closures at Partial weakened or blocked traffic lanes. Closure, Full Complete closure of a structure. Activities needed to establish alternate routes around restricted or closed Detour structures. Temporary Deployment and maintenance of temporary bridges. Bridge
OCR for page 27
27 Table 18. Clean/clear--frequent uses of activities. Clean/Clear Bridge Components Wash All except earth slopes and banks. Zone wash All except earth slopes and banks. Sweep Decks, Joints, Approach pavement, Substructures. Flush All except earth slopes and banks. Unclog /cleanouts Drains. Graffiti Superstructure, Substructure, Parapets/Sidewalks, Culverts. Vegetation /trees Earth slopes and banks. Debris /Drift Substructures, Channels, Culverts. earth slopes and banks; Sweep applies to horizontal surfaces, equipment for movable bridges, but not other equipment. A but not vertical ones; Unclog applies to drains but not to open list of likely applications of reset activities with bridge com- surfaces; Vegetation control applies to earth slopes and banks, ponents is shown in Table 19. but not to structural components. A list of likely applications of Clean/Clear activities to bridge components is shown in Coat/Paint Operations. Among the activities for Coat/ Table 18. Paint operations: Paint applies to structural components, but not earth slopes and banks; Sealing applies to concrete and Reset Operations. Among the activities for Reset opera- bituminous surfaces usually; Chemical Treatments apply to tions: Consumables maintenance applies to light bulbs, rub- timber elements, and to control of vegetation. A list of likely ber parts of joints, but not other bridge components; Tighten applications of coat/paint actions with bridge components is applies to threaded parts; Caulk applies to fixed, closed joints shown in Table 20. in components, but not other joints; Lubricate applies to moving joints, bearings and rails, but not other parts; Gates/ Repair Operations. Among the activities for Repair oper- Signals applies to traffic control on movable bridges, but not ations: Patch applies to concrete structural components and other traffic control; Equipment maintenance applies to motion bituminous wearing surfaces; Re-attach applies to anchors for Table 19. Reset--frequent uses of activities. Reset Bridge Components Consumables Bridge (lights), Joint seals. Tighten All components having bolts or rods. Caulk All except Embankment, Channel. Lubricate Bearings, Railings (at joints). Reposition Bearings, Railings, Channel (protection), Movable Span. Gates and signals Movable span. Mechanical equipment Movable span. Electrical equipment Movable span. Table 20. Coat/paint--frequent uses of activities. Coat/Paint Bridge Components Paint All except Embankments, Channels. Spot paint All except Embankments, Channels. Concrete or Bituminous elements of Deck, Wearing surface, Seal surface Parapets/Railings/Sidewalks, Superstructure, Substructure, Embankment (protection), Culvert, Movable Span. Concrete or Bituminous elements of Deck, Wearing surface, Seal cracks Parapets/Railings/Sidewalks, Superstructure, Substructure, Embankment (protection), Culvert, Movable Span. Chemical Preservatives for Timber Deck, Railings, Superstructure, Substructure, Culverts and treatment Movable Spans. Herbicides/Pesticides for earth slopes and banks. Surface All structural components. prep
OCR for page 28
28 Table 21. Repair--frequent uses of activities. Repair Bridge Components All concrete or bituminous Deck/Wearing course, Parapets/Railings/Sidewalks, Patch Superstructure, Substructure Approach/Embankment (protection), Channel (protection), Culvert, Movable Span. Deck (grate), Joints (armor), Joint (seal), Drains, Parapets/Railings/Sidewalks, Re-attach/ Superstructure, Bearings, Substructure, Channel (protection), Culvert (metal), re-anchor Movable Span. Parapets/Railings (metal), Superstructure (metal members), Substructure (metal Straighten elements), Culvert (metal), Movable Span. Jack/Align Approach slabs (mudjack), Substructures, Culverts. Reinforce/ Deck (structural), Parapets/Railings/Sidewalks, Superstructure, Substructure, Culvert, Strengthen Movable Span. Dredge/ Approach/Embankment, Channel. Grade joint, bearings, railings, etc.; Straighten applies to metal ele- Table 22. Replace--frequent ments; Jack applies to components that have tilted or settled; uses of activities. strengthen applies to structural components; Dredge/Grade Replace Bridge Components applies to earth slopes, banks, and channels. A list of likely Individual Unit, all components. applications of Repair activities with bridge components is Section All components shown in Table 21. Complete All components Span All components Replace Operations. Among the activities for Replace operations: Individual applies to items such as joints, bear- ings, railing sections and beams where the component is a collection of similar elements; Section applies to decks, wear- ponents; strength applies to increases in load rating for struc- ing surfaces, and other components that are continuous; tural components, and increases in motion or flow capacity Complete is full in-kind replacement of a component; span is for joints, drains, bearings and channels; Function applies to complete replacement of a component in one span of a multi- changes in load path or movement regime; Assembly applies span bridge. A list of likely applications of Replace activities to upgrades of joints, bearings, railings and other devices. A with bridge components is shown in Table 22. list of the frequent uses of Modify activities with bridge com- ponents is shown in Table 23. Modify Operations. Among the activities for Modify operations: Geometry applies to improvements to clearances; Emergency Operations. Among the activities for Emer- protection applies to new protection of structural components gency operations, Post applies to structural components; Shore against corrosion, or channels against scour; Vulnerability applies to any component needing additional support; Clo- applies to the potential for sudden failure of structural com- sure applies to bridges and culverts; Detour applies to bridges Table 23. Modify--frequent uses of activities. Modify Bridge Components Geometry Bridge, Superstructure, Parapets/Railings/Sidewalks, Culvert, Movable Span. Bridge, Deck, Parapets/Railings/Sidewalks, Superstructure, Substructure, Protection Approach/Embankment, Culvert, Channel, Movable Span. Bridge, Parapets/Railings/Sidewalks, Superstructure, Substructure, Culvert, Channel, Vulnerability Movable Span. Strength/ Bridge, Deck, Parapets/Railings/Sidewalks, Superstructure, Substructure, Culvert, capacity Movable Span. Bridge, Deck, Joints, Drains, Parapets/Railings/Sidewalks, Superstructure, Bearings, Function Substructure, Movable Span. Assembly Bridge, Parapets/Railings/Sidewalks, Movable Span.