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9 Exhibit 2. Terms describing bridges. Bridge: A structure carrying traffic over a span of greater than 20 feet, as defined in NBIS (Ref 42). Culverts, as defined in NBIS. Component: One among the major regions or assemblies of a bridge. There are five NBIS components (deck, superstructure, substructure, channel, culvert), and six additional components that are objects of maintenance (joints, drains, railings, bearings, approaches, movable bridge). Element: One among AASHTO's commonly recognized elements, or among additional elements defined by DOTs. Device: A part that can be replaced as a unit, often without demolition of attached portions of the bridge. estimated quantities intended to deliver a specified level of ponents that appear in the NBIS (deck, superstructure, sub- service along a route. structure, channel, culvert) plus six components that are identified in maintenance work (joints, drains, railings, bear- Summary on Bridge Maintenance Scope ings, approaches, movable bridge). Bridge elements include AASHTO's commonly recognized bridge elements (1) plus Bridge maintenance can be defined in terms of policy additional elements defined by DOTs. Bridge devices are pre- statements, lists of actions, budget status, and the capabil- fabricated parts such as railings or bearings that can be replaced ities of maintenance data systems. U.S. DOTs recognize maintenance as distinct from new construction, replacement as individual units (Exhibit 2). of structures, and major rehabilitation of structures. Clean- An Operation is a kind of maintenance (Exhibit 3). An ing, painting, and minor repairs are always maintenance. Activity is a general method for an operation. A maintenance Replacement or modification of portions of bridges may be Event is the accomplishment of one operation, on one bridge, maintenance if projects are small and have a short duration. at one time. A maintenance Record is the collection of data for Large projects are construction, rather than maintenance. one maintenance event. A maintenance Item is the identifica- Emergency work, usually in response to accidents or extreme tion, usually by a numerical code, of a maintenance action. events, is classified as maintenance and can entail significant, Costs of maintenance are computed from usages of temporary modifications of bridges. resources. Resources include Labor, Equipment, and Materials for DOT crew work, and pay items and quantities for contract maintenance (Exhibit 4). Labor costs are sums of employee Terms in Bridge Maintenance hours and labor rates. Equipment costs are sums of equip- This section reports a set of frequently used terms in bridge ment usage and equipment rates. Material costs are sums of maintenance. Chapter 6 provides a glossary of terms collected material quantities and unit costs. Contract costs are sums of from DOT maintenance manuals and guides. pay Item quantities and bid prices. Maintenance Accomplish- Bridges are structures included in the National Bridge Inven- ments are quantities of maintenance work completed. These tory System (NBIS) (35). Bridges may include short spans may be expressed in units specific to maintenance operations, and minor culverts. Bridge components include the five com- or as quantities of bridge elements that receive maintenance. Exhibit 3. Terms describing maintenance work. Operation: A type of maintenance work, being one among: Clean, Reset, Coat, Repair, Replace, Modify, Emergency. Activity: A method of performance of an operation. Event: The accomplishment of an operation at a specific structure, on specific dates, in specific quantities, incurring specific costs and delivering specific improvement. Record: Data for one event, identifying the structure, the action, the date, the resources used, the action quantity accomplished, and the improvement to bridge condition. Item: The identifying number of a maintenance action.
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10 Exhibit 4. Terms related to maintenance cost. Resource: Any measurable contributor to the cost of maintenance. Resources include labor, equipment, materials, and pay items. Labor: As a resource, the set of employees and hours. As a cost, the sum of products of hours and rates. Equipment: As a resource, the set of equipment types and usages. As a cost, the sum of products of equipment usages and rates. Materials: As a resource, the set of material items and quantities. As a cost, the sum of products of material quantities and unit costs.. Pay Items: As a resource, the set of pay items and quantities. As a cost, the sum of products of pay items and bid prices. Accomplishment: The quantity of maintenance work that is completed, expressed in action units, or bridge element units or both. Outcome: Improvement to condition ratings or road survey data achieved by a maintenance event. Maintenance Outcomes are the improvements to bridge con- used for AASHTO's commonly recognized bridge elements. ditions achieved by maintenance events. Road Surveys report presence of debris, graffiti, and other defi- Most DOTs recognize categories of maintenance. These are ciencies in upkeep along routes and at bridges. Similar data variously called Scheduled/Response, Preventive/Routine, or may be called maintenance assurance values, maintenance Proactive/Reactive. These terms have different and sometimes quality data, or simply field data. Condition ratings and con- conflicting meanings for different DOTs. Exhibit 5 lists these dition states are usually reported by bridge inspectors. Road terms as they are defined by AASHTO and by DOT sources. survey data are reported by road maintenance crews. Condition ratings are integer values indicating the presence and severity of defects at bridges (Exhibit 6). In practice in the Summary on Maintenance Terms United States, ratings usually denote the 9-to-0 scale used in the NBIS and applied to bridge components. Condition States Selected terms describing bridge features, maintenance work, are also integer values indicating the presence and severity of costs, and condition data are defined in this section. Most of defects. States usually denote the 5-valued and 4-valued scales these terms are familiar, and the definitions given here are com- Exhibit 5. Terms describing maintenance categories. AASHTO (2) Scheduled: Work programmed at intervals. Response: Done as needed and as identified through the inspection process. Alabama (11) Routine Limited Activities: Quantities of work that can be established and firmly adhered to. Control is exercised on the basis of planned work units. Examples: Mowing, Bridge Inspection. Routine Unlimited Activities: High priority work performed when needed in the amounts required to minimize deficiencies. Oregon (20) Proactive: Activities planned in advance to reduce lifecycle costs; inspection, upkeep. Proactive: Activities planned in advance to forestall significant damage. Preservation or restoration activities. Reactive: Incident driven activities. Performed to correct or respond to immediate problems. Texas (21) Preventive Maintenance: Steel structure cleaning and repainting; installation of other coatings; installation of bridge deck protection; joint cleaning and sealing or replacement. Routine Maintenance: Repair of substructures, superstructures, decks, joints, approach slabs, and railing; spot painting; repair and operation of movable bridges; installation of temporary bridges; repair and installation of fender systems.