Highway Maintenance Response Time Standards

DRAFTFigure 4. Statewide Bridge Condition Trend Since 1994.40Percent Deficient by Number35302532.930.930.229.529.328.428.327.927.827.327.4201994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004YearFigure 5 shows the distribution of bridge condition ratings. Notice the buildup of bridgesjust above the 5 level. Preventive and design modification (corrective) maintenanceactions are needed to keep these bridges from deteriorating and entering the deficiencyrange. Bridge preventive or “cyclical” maintenance targets treatments applied at regularintervals to counter accelerated deterioration caused by environmental factors.Bridge design modification (corrective) maintenance actions target specific bridgeelement deficiencies. Historically called the “5 to 7” program, these treatments such asbearing replacement, and spall repair improve the overall structural integrity of thebridge and thus provide a positive effect on the condition rating. Figure 6 shows thebenefit of the Department’s corrective maintenance program. As can be seen from thisfigure, corrective maintenance significantly extends bridge service life. Withapproximately 27% of the bridge population at condition ratings between 5.0 and 5.5, anaggressive corrective maintenance program is needed to prevent these bridges fromslipping into the deficient category.22