(Demo) Road and Bridges May 2010 : Page 32
risk is reduced or that preventive mainte- nance needs have been satisfi ed. Verifi ca- tion often requires integration of DOT data systems. The bridge-management applications used by crews, program managers and planners need to remain current, and the inventory condition must refl ect all actions and repairs. Preventive maintenance Bridge preventive maintenance has The Virginia DOT developed the Dashboard application as an easy-to-understand means of tracking the overall health of the state’s highway system. Performance measures also must be matched to objectives in bridge main- tenance. Measures must both identify work needed to advance maintenance objectives and provide simple indica- tions of bridge network status. Some states have developed a bridge-preser- vation allocation formula with rules to replace those bridges that rate less than an NBI 4 (poor condition), to rehabili- tate the structures that rate 4 or 5 (fair to poor condition) and to use preventive maintenance on those bridges that rate above 5 (fair to good condition). States have developed and use many other performance indicators. Examples include the count of bridges with back- logged maintenance work; the count of structurally defi cient and functionally obsolete bridges; the network average bridge health index (BHI) (average of total quantities of elements); the count of bridges with BHI < 80; and level of service (LOS) for bridges computed as crew work that is backlogged divided by the full work list for the crew. Prioritization: Prioritization of maintenance projects should integrate agency objectives for defi cient bridges and preventive maintenance on good bridges. The process for prioritization must recognize the effect that deferred maintenance will have on individual bridges and on the network of bridges. An automated evaluation of priorities would include a multiobject approach that combines the benefi ts of least cost, risk reduction and preventive maintenance. Inputs to automated evaluations should include bridge conditions, bridge vulnerabilities (such as seismic and scour), indicators for program managers’ 32 May 2010 • ROADS&BRIDGES needs (such as paint-health index) and attributes of the bridge inventory. Procedures for prioritization must engage both central and regional DOT offi ces and must advance from network- level rankings of candidates to bridge- by-bridge project selection. On the subject of the bridge-by-bridge selection, the involvement of inspectors, main- tenance crews and district engineers is paramount. They are very familiar with the local bridge inventory; their knowl- edge validates both the priorities list and the network plan. Bridge conditions, for example, can be categorized as poor, fair or good and correspondingly color-coded as red, yellow or green. This rating method can be somewhat subjective, since the states’ defi nitions of a good bridge can vary. Within this accepted color-coded approach, taking care of yellow bridges on the cusp of becoming red bridges reduces the number of bridges that will eventually fall into the red, thus averting the need for more costly replacements. A holistic approach to prioritization would also include spending great efforts to keep green bridges green. Through preventive maintenance activities, bridge owners can maximize the number of green bridges and reduce the need to do more costly repairs and rehabilitation. Bridge owners must consciously and consistently work to keep good bridges in good condition, rather than be in a continual juggling act with the bad. Verifi cation: The bridge-management process must incorporate reports of completed maintenance work and the verifi cation, at completion, that the bridge conditions are improved and the been defi ned as cost-effective mainte- nance actions that extend the useful life of a structure. Scan states had differing views of what qualifi ed as preventive maintenance. Activities included such things as routine cleaning, joint repairs, deck treatments, deck replacements, bridge painting, retrofi ts and other cyclic actions. These activities are performed by most states on some level. To be most effective, preventive-maintenance actions need to occur while a bridge is in relatively good condition. This proactive approach to preventive maintenance prolongs the life of a struc- ture. Experience in scan states has shown that a preventive-maintenance approach is cheaper in the long run (even if per- formed frequently) than a major bridge rehabilitation or replacement approach that both is costly and disrupts mobility. A signifi cant portion of bridge resources (funds, personnel and effort) can be directed to preventive main- tenance. Preventive maintenance can succeed in maintaining good bridge con- ditions, and the actions must be applied before bridge conditions become poor. DOTs must be able to recognize cur- rent needs for preventive-maintenance actions, anticipate near-term needs and follow work programming procedures that deliver preventive-maintenance actions promptly. To recognize and program preventive maintenance, DOTs require trained staff, adequate funding, fl exible fund allocations and clear plans of action for bridge components. These last two aspects—allocations and plans— are key. As already noted, funding should be directed to preventive maintenance before bridges become defi cient. DOT staff should recognize mainte- nance needs related to time in service and not only to the defects extant. These actions preserve the condition, improve
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