Terms and Definitions
- Fracture-Critical
A fracture-critical bridge is one that does not contain redundant supporting elements. This means that if those key supports fail, the bridge would be in danger of collapse. This does not mean the bridge is inherently unsafe, only that there is a lack of redundancy in its design.
- Functionally obsolete:
A bridge that is functionally obsolete is not necessarily unsafe. This category indicates the bridge has older design features not built to today's standards. A functionally obsolete bridge is likely not wide enough or tall enough to accommodate current vehicle sizes, weights and traffic volumes.
- Not Deficient:
A Bridge that is neither structurally deficient nor functionally obsolete.
- Structurally Deficient:
A bridge that is structurally deficient is not necessarily unsafe. This category indicates the bridge has elements that need to be repaired and/or monitored. A structurally deficient bridge should be maintained, inspected and monitored on a regular basis.
- Sufficiency Rating:
The Sufficiency Rating is calculated from a complex formula (developed by the FHWA) using 18 data items from the Structural Inventory and Appraisal (SI&A). A number (or rating) is generated from 0 to 100 indicating the bridge's structural and functional condition. The 100 possible points are allocated as follows: 55 points for "Structural Adequacy and Safety", 30 points are for "Serviceability and Functional Obsolescence", and 15 points for "Essentiality for Public Use".
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Know Your Limits- Kentucky Bridge Weight Limits for Emergency Vehicles
Emergency Vehicles (EVs) are designed to be used under emergency conditions to transport personnel and equipment to suppress fires and mitigate other hazardous situations (23 U.S.C. 127(r)(2)).
Under this provision, the gross vehicle weight (GVW) limit for EVs is 86,000 pounds (pursuant to Section 1410 of the FAST Act).
The Bridge Weight Limits map displays weight restricted bridges EV operators should avoid if they do not meet the posted weights. There are two ways to search for bridges in your service area that may be restricted from use:
- See our Weight Limits interactive map. Once on the page, click the magnifying glass icon in the top right corner of the map, select “gross posted or EVs restricted” from the search layer dropdown menu,
select your county, then click search. All of the bridges in blue have a known restriction. Double-click the icon to see bridge weight details. If the EV exceeds ANY of the four posted weight limits for the bridge, then the EV is not permitted to use the structure.
See Interactive Map here.
- See a list of bridge weight limits for emergency vehicles by county
here.
The statute authorizes the following additional weight limits, depending upon vehicle configuration: 1 ton= 2000 pounds
- 24,000 pounds on a single steering axle;
- 33,500 pounds on a single drive axle;
- 62,000 pounds on a tandem axle; or
- 52,000 pounds on a tandem rear drive steer axle.
If the Emergency vehicle exceeds the gross posting, the vehicle is restricted; otherwise if the vehicle exceeds any of the listed single axle, tandem axle, or EV gross posting- the vehicle is restricted from utilizing that structure.
Questions? Contact Division of Maintenance, Bridge Preservation, 502-564-4556.
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