III. REPAIR SEQUENCE GUIDANCE

This chapter provides guidance on how to repair W-beam guardrail sections. Some critical actions you should take before the actual repair include:

• Upon notification of damage and when the damage leaves the guardrail nonfunctional, and it cannot be repaired immediately, warn traffic of the hazard by putting out temporary warning devices in accordance with the MUTCD, such as drums, vertical panels, cones, or other devices.
• Contact your local Dig Safe utility protection well in advance of going to the site.
• Take enough signs and channelizing devices to the site to properly mark the repair zone. When your agency uses an arrow board and / or a shadow truck or Truck Mounted Attenuator (TMA), be certain there is enough equipment and personnel to handle these items.
• et up the Temporary Traffic Control plan for the work area to repair the guardrail, and ensure the Traffic Control Plan complies with the Manual on Uniform Traffic Control Devices (MUTCD) or your agency requirements.
• Ensure all workers wear equipment as provided by the Occupational and Safety Administration (OSHA) or local requirements, such as safety visibility vests, safety glasses, and protective-type shoes.
• Ensure all equipment and procedures conform to accepted OSHA guidance.

The remaining portion of this chapter is divided into standard and transition sections, and end treatments

STANDARD AND TRANSITIONS SECTIONS

The following sequence is usually followed in repairing the standard or transition sections:

1. Disassemble damaged guardrail.
   1. Spray the connecting bolts with penetrating oil for easier removal. Unbolt the damaged rail-beam sections.
   2. If the elliptical shoulder is worn off the bolt, then hold the smooth round head with vise grips to unscrew the nut. Use a torch to cut stubborn bolts. Do not torch cut rail sections to be reused.
2. Pull out damaged posts.
   1. Steel posts can often be worked out by hand or with a crowbar. Crews may have to use a chain and hoist to dig or pull wood posts.
   2. Slightly twisted steel posts still firmly in the ground can often be straightened in place by pulling with a chain attached to a truck. Provide traffic control warning if the truck's operation encroaches on the traveled roadway. Use a crowbar to pull posts only pushed off-line back into line.
3. If necessary, use a grader to reshape the shoulder area and recompact the soil for posts. If placing new post(s), then rework the area before installing the post(s), if practical.
4. Set up a stringline to position posts at the proper height, alignment, and spacing. If repairing more than two panels, then set the W-beam to the standard height. It is relatively easy to create up to a 4-in change in height over one panel length. (When the rail height is not adjusted and is 3 or more inches below standard, report it to your maintenance supervisor.) Mark the stringline for the proper post height and alignment. Use a tape or a measuring stick to mark the proper post spacing.
5. Drill or dig holes for the posts, if necessary.

   

6. Set or drive posts to the proper height.
7. Backfill and compact the soil around the posts.
8. Check post alignment and height. Correct any major deviations.
9. Starting downstream and working backwards, loosely hang new rail sections and offset blocks. Lap rail elements in the direction of traffic. In general, do not use washers under the bolt heads of the rail-to-post bolts. When using steel posts with steel offset blocks, a back-up plate is needed at the intermediate posts (the posts between the rail splices).
10. If necessary, use a drift pin to line up the holes for bolting.
11. Make sure all 8 bolts are in place in each splice connection.
12. Leave all connections finger tight to allow for lengthwise adjustment after all sections are installed.
13. Final assembly – when all rail is hung, go back and snugly tighten all bolts. There is no need to overtighten.
14. Cleanup – smooth out the shoulder and slope approaching the guardrail so the next vehicle to run into it has a smooth path.
15. Install guardrail-mounted delineators and, if appropriate, object hazard markers.

Make a final inspection before leaving the site. Complete the suggested checklist at each location to document the work.

Completed Work Inspection Checklist
(Standard Section and Transitions)

• ____Do all splices have eight bolts; have all bolts–both splice and rail–to–post–been checked to see that each is tightened snug?
• ____Is a blockout used on each post?
• ____Guardrail height was checked to make sure it is correct and did not shift up or down out of tolerance during the final assembly?
• ____Deflection distance is provided from any vertical, rigid object or the W-beam system appropriately stiffened?
• ____Adequate soil backing is provided behind the posts; if not, are longer posts used?
• ____ A nail(s) is driven in each wood blockout on wood posts to toenail the block to the post to prevent rotation?
• ____ If steel blockouts are retained, does each steel post between the splices have a back-up plate behind the rail element?
• ____ Were all washers between the bolt head and the rail element removed (unless required) from the repaired W-beam length?
• ____ Is the lap of the rail elements correct?
• ____ Are guardrail-mounted delineators located properly on the guardrail?
• For repair including transitions:
• ____ Are the four (minimum) ⅞-inch-high strength bolts properly anchored and NOT protruding significantly in front?
• ____ Is the last rail element nested?
• ____ Are there enough/properly sized posts adjacent to the rigid object?
• ____ Has a means to prevent wheel snagging (rub rail or curbing) been applied, if necessary?
• ____ Is the lap of the bridge shoe correct?

Date repair completed: _________________________

Repair completion inspected by:______________________________ (Signed)

END TREATMENT SECTION

The following steps are suggested for end treatments:

1. Remove the damaged hardware as described for the standard W-beam section. If the end treatment is an energy-absorbing type, and the impact head is pushed down the rail element, cut off the deformed steel and pull off the head – do not cut the rail or unbolt the splice downstream of the head until the head is removed. Guidance for determining whether an impacted head can be reused: Reuse it when there is obviously no damage; replace it if questionable.
2. For damage meeting criteria that requires replacing the whole end treatment, check the LON to determine if appropriate W-beam length is available to adequately shield the hazard. Add any standard W-beam as deemed necessary before installing the new end treatment. Provide the necessary grading platform prior to constructing any end treatments.

Because of the many possible options that repair/replace damaged end treatments, it is virtually impossible to give detailed instructions for their treatment. However, two items must be discussed.

Many different types of posts are used in the different end treatments, both generic and proprietary. Examples are:

• Weakened wood posts, called CRT posts, that are 6 ft long and have 3½-in-diameter holes drilled at ground line and 16 inches below the ground.
• Short wood posts 45 inches long with a 2½-in hole, which slip into steel foundation tubes driven in the ground –foundation tubes have different lengths and may or may not have soil plates attached to them.
• Steel posts that come in two parts and are attached by bolts at the ground line.
• Steel posts having two parts that are plug welded together.
• Steel posts that look like standard 6-ft steel posts, but have four holes in the flanges at ground line; and more.

Because of this variety, make a detailed inspection of the type in the existing installation. Replace damaged posts in an installation that is only to be partially repaired with the same type of the original posts. However, several manufacturers have developed steel posts that facilitate repair – be sure to check with each manufacturer for approved variations and mixing of post types before using a post type different than the damaged one(s).

To repair or replace any proprietary types of end treatments, it is imperative that crews have the manufacturer's shop drawings and installation manual on site during repairs. Installation manuals also contain guidance for repairing damaged installations and can be used on generic installations as well, such as removing the wood stub left in a foundation tube.

Completed Work Inspection Checklist (End Treatments)

• ___Is the anchor cable properly attached to the rail element?
• ____Is the grading correct under the appropriate standard (including 4-in stub height requirement for post foundations and for struts)?
• ____ Will post 1 separate from its base on end-on impacts?
• ____ Has the LON been reviewed for appropriateness?
• ____ For energy-absorbing end treatments, is the rail element inserted deeply inside the head, and is there NO bolt connecting the rail to post 1?
• ____ Is the bearing plate properly oriented and restrained from turning?
• ____ Are all rail-to-post bolts located according to the manufacturer's drawings?
• ____ Is the anchor cable taut?
• ____ Are all wood block-outs on wood posts properly toenailed to prevent rotation?
• ____ Is the object (hazard) marker installed?

Date repair completed: _________________________

Repair completion inspected by: ______________________________(Signed)