Bridges
- Bridges
- Restricted Bridge List
- Carrying Capacity of a Bridge
- Bridge Inspections (BIM)
- Jim Bob Bridge
- Bridge Types
Throughout the County there are 96 bridge size culverts, 91 standard bridges & 10 major bridges for a total of 197 structures with an additional 4 Jim Bob bridges ready for use.
Some of these bridge structures have weight, height and/or width restrictions for various reasons. For a detailed list of these restricted bridges go to the Restricted Bridge List tab to the left.
The sign in Figure 1 is the sign for posting the carrying capacity of a restricted bridge.
Figure 1
The uppermost symbol and the SINGLE column in the restricted bridge list apply to:
- a single unit truck
The middle symbol and the SEMI column in the restricted bridge list apply to:
- a truck and a trailer
- a truck tractor and a semi-trailer, in the case where the inter-axle spacing between the truck tractor and the semi-trailer is 4.5 metres or more
- a mobile crane with a boom dolly
- a truck tractor in combination with a single axle semi-trailer and a semi-trailer
- a truck tractor in combination with a single axle semi-trailer and a pole trailer
The bottom symbol and the TRAIN column in the restricted bridge list apply to:
- a truck tractor in combination with 2 or more trailers
- a truck and a full trailer with tandem axles, in the case where the inter-axle spacing between the tandem axle groups is 5.0 metres or more
- a truck tractor in combination with a tandem axle semi-trailer and a semi-trailer
- a truck tractor in combination with a tandem axle semi-trailer and a pole trailer
The numbers on the restricted bridge sign indicate the maximum allowed gross vehicle weight, in tones, for each category of vehicle.
The County has the bridges inspected through the Bridge Inspection and Maintenance (BIM) System. The Bridge Inspection and Maintenance (BIM) System is an inventory and management system developed in the 1960s and 1970s by the Alberta Government. The reason for the inspections and the data management is to provide a coordinated system to ensure an appropriate level of safety for the travelling public. The province trains and certifies inspectors who fill out the forms and submit them for entry into the provincial database. The inspectors inspect structures, make recommendations, and notify the appropriate stakeholders or authorities if action needs to be taken. The inspections themselves are entered into the provincial database which is open to any individual who is involved in the maintaining or replacing of the bridges/culverts. The data can be used for planning, maintenance schedules, design, etc. (from the Alberta Transportation BIM manual).
A BIM is a visual inspection only. The inspectors are trained what to look at, what types of structures will show deterioration in which ways, but it is still just visual. If an inspector feels an element of a bridge or culvert warrants a closer look, they may recommend a more specialized inspection as a follow up. Due to the additional equipment and expertise required to perform the specialized inspections and often the need for additional personnel for safety these inspections must be done at another time. During the inspection’s deficiencies are noted and, in some cases, work to repair the bridge would be tendered out. As a structure ages, inspections are completed on a shorter cycle and the bridge may also have weight restrictions attached. This program has greatly extended the lifespan of the structures and reducing replacement costs.
Bridge inspections are used to update the 3-year Bridge Plan presented annually to Council and to provide information to compile the works necessary to produce the Bridge Maintenance Contract.
Jim Bob bridges are a suitable tool for keeping roads open when a bridge is rated to such a low tonnage that heavier traffic could not travel over it. A Jim Bob can be trucked in and placed across the existing structure in about 1 day thereby keeping the local road open until a new bridge has been designed & budgeted for.
