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Bridge Condition Measures

Structurally Deficient Bridges Report

One of the most prominent measures of bridges is whether or not a bridge is structurally deficient. A structurally deficient (SD) bridge is one for which the deck (driving surface), the superstructure (supports immediately beneath the driving surface), or the substructure (foundation and supporting posts and piers) are rated in condition 4 or less on a scale of 1-10. Structural deficiency does not necessarily imply that a bridge is unsafe. It does, however, mean that a structure is deteriorated to the point of needing repairs immediately to prevent restrictions on the bridge. The ABP Goal is to reduce to 450 the number of SD bridges by 2016.

MassDOT Trend of Structurally Deficient Bridges 1996-Present
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MassDOT Trend of Structurally Deficient Bridges 1996-Present

From 1996 to 2006, the number of structurally deficient bridges dropped from 669 to 502 as shown. These improvements reduced the percentage of SD bridges in the state from 15% to 11%. Since 2006, the number of structurally deficient bridges in Massachusetts has remained relatively constant. Recent investments in preservation are beginning to reverse the trend of adding to the SD inventory.

MassDOT Number of SD Bridges Added vs. SD Removed – August 2007 to Present
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MassDOT Number of SD Bridges Added vs. SD Removed – August 2007 to Present

This chart shows the number of bridges that became structurally deficient and the number of bridges that were removed from the list of structurally deficient in each month since April 2008. As this chart indicates, through June 2008 bridges became structurally deficient at a faster rate than MassDOT was able to remove bridges from structurally deficient status. This trend is due in large part to unmet maintenance needs on many of Massachusetts’ bridges, especially older bridges. In August 2008, Governor Patrick signed the Accelerated Bridge Program into law to reverse this trend. Recent investments are improving the trend.

DCR Trend of Structurally Deficient Bridges 2005-Present
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DCR Trend of Structurally Deficient Bridges 2005-Present

From 2005 to present, the number of DCR structurally deficient bridges increased from 21 to 27 out of 106 bridges. The Accelerated Bridge Program will help to reduce the number of DCR SD bridges.

Bridge Health Index Report

MassDOT and DCR also measure bridge condition with Bridge Health Index. Bridge Health Index is the ratio of the current condition of each element to perfect condition expressed as a score from 0 to 100, with a value of zero indicating all of particular bridge’s elements to be in the worst condition. A bridge health index of 85 would indicate that the condition of a system of bridges to be good. Health Index is especially useful to characterize the physical condition of a bridge or set of bridges. Health Index provides MassDOT and DCR bridge engineers with a way of assessing the overall conditions of all bridges, or subsets of bridges, in Massachusetts.

MassDOT Health Index Report
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MassDOT Health Index Report
DCR Health Index Report
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DCR Health Index Report
Health Index By Road Category
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Health Index By Road Category

The above chart shows a comparison the Health Index of bridges on Interstates, US and State Highways, and local roads. The condition of bridges on the interstates is higher than the condition of US, State, and Local Roads. These better condition of bridges on the interstate system is attributed to the increased focus and funding assistance for Interstate Bridges. Improving Interstate Bridge Health is also a priority of the ABP.

In the Spotlight

Active Project List [PDF - 231KB]

ABP Update
Through April 1, 2014 the MassDOT Accelerated Bridge Program has advertised 191 construction contracts with a combined construction budget valued at $2.26 Billion.
Of these 191 advertised construction contracts:
  • 152 have already, or will, repair/replace over 270 bridges throughout the Commonwealth.
  • 39 are maintenance/preservation projects which perform work to improve the safety of many additional bridges throughout the Commonwealth.
  • 187 have been awarded to a contractor.
  • 155 have been declared complete by MassDOT (or DCR) with two additional contracts terminated and the remaining scope transferred to other contracts.
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