Section 4: Roadside Sign Supports
Anchor: #i1002281Introduction
This section contains maintenance information and procedures for roadside sign supports (posts). Additional information concerning sign supports can be found in Chapter 3 of this manual.
Anchor: #i1002326Keeping Posts Straight
Sign supports should be maintained in a vertical upright and plumb position to provide the best appearance along the roadway.
Anchor: #i1002346Breakaway Posts
Breakaway sign supports should be maintained to assure performance of the breakaway feature.
On rectangular slip base sign supports, the slip base plate and fuse plate connection bolts should be examined for proper tightness, and the fuse plates and post-flanges should be examined for cracking or failure. (See the Traffic Engineering Standard Sheets for details.) Over tightening of the base plates can cause the support not to break away properly.
The bolt keeper plate for bolted breakaway sign posts should be in place between the stub post base plate and the sign post base plate to ensure that the sign support system functions properly. Also all washers should be installed as shown on Traffic Engineering Standard Sheets.
The foundation should also be checked for erosion of surrounding soil.
Anchor: #i1002356Straightening Bent Posts
Damaged galvanized metal supports should be straightened if reasonably possible. Any damage to the protective coating should be repaired with a zinc-rich coating (available from the appropriate regional distribution center).
Anchor: #i1002366I-beam Supports
Large, ground-mounted guide signs are supported with a steel I-beam support system that breaks away when hit by a vehicle. High wind gusts sometimes blow the sign over, with failure at the “hinge.” See the Traffic Engineering Standard Sheets for hinge details.
The tension fuse plate can be ordered from the regional distribution centers. The fuse plate is listed as: “PLATE, FUSE, galvanized.” Fuse plates are ordered by size to fit the post, and all bolts, nuts, and washers must be ordered separately.
Anchor: #i1002396Repair of Large, Ground-Mounted Guide Sign Supports
The following procedure may be used to repair large, ground-mounted guide sign supports when the foundation and post below the hinge point are undamaged:
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- Saw or torch cut through post width, making edges level and smooth. Anchor: #IHSCEKDX
- Clean cut surfaces to near-white metal by wire brushing, light grinding, or mild blasting. Cut surfaces should be clean, dry, and free of all grease, welding slag or flux, and corrosion products before application of organic zinc-rich paint. Anchor: #MRWOTQII
- Install fuse plates and reassemble post with H.S. hex-head bolts, hex-head nut, and washers. Use washers as shown in the Traffic Engineering Standard Sheets. New fuse plates, bolts, nuts, and washers should be used. Anchor: #KFVBPHXS
- Torque all bolts as required by specifications. Anchor: #LOXNDJTW
- Apply zinc-rich paint to cleaned cut surfaces as per manufacturer’s recommendations.
Tension Fuse Plate. All holes must be drilled. All plate cuts should be saw cut; however, flame cutting is permissible provided all edges are ground. Metal must not project beyond the plane of the plate face. Steel fuse plates must conform to the requirements of the Traffic Engineering Standard Sheets.