4B-3: Removing or Abandoning Culverts

This section presents information related to removing or abandoning culverts.  When an existing culvert no longer serves its purpose, it may be removed or it may be left in place (abandoned) and filled with flowable mortar.  Every job is different so each case needs to be reviewed individually to determine the best course of action.

Removing a Culvert

Usually, culverts will be removed.  If there is a conflict with the culvert being in the way of new construction, then the culvert must be removed.  The most common example is an old culvert that is to be replaced with a new one in the same location

Pipe Culverts

Pipe culverts to be removed on grading projects should be noted as such on the plan and profile sheet.  Removal is incidental unless the pipe culvert has been encased in cast in place concrete (see Section 2102.04 of the Standard Specifications).

R.C.B.Culverts

All R.C.B. culverts not used for future drainage should be removed.  R.C.B. culverts to be removed should be included in the tabulation for the removal of structures and paid for by lump sum with size of existing R.C.B. noted. The option of filling the structure with flowable mortar in lieu of removing the structure is determined by consultation with the Soils Design Section and the Office of Bridges and Structures.

Livestock Passes

For the removal of a livestock pass, refer to Policy No. 610.06 of the Policy and Procedures Manual.  If a livestock pass has water flowing through it, a smaller pipe may be inserted into the livestock pass to maintain the flow.  Contact the Preliminary Bridge Section to determine the proper pipe size.

Abandoning a Culvert

All culverts that are abandoned should be filled with flowable mortar.  They must be shown and referenced on road plans to avoid future problems.  Very long or tall culverts may require drilling holes in the pavement or shoulder to introduce flowable mortar.  This will reduce the risk of voids in the middle of the structure.

When the culvert is to be filled and abandoned, the headwalls of the culvert may need to be removed, depending on the situation.  On a smaller construction job, such as resurfacing where there is no significant earthwork being done, the headwalls need to be removed if located within the clear zone because the remaining exposed section is an obstacle.  On major construction projects where the headwalls will be covered with fill during the grading process, the headwalls can remain in place because they will no longer be an obstacle.

Documentation

Road Design Detail 4315 or 4316 should be used in the plans for filling and abandoning a culvert.  Tabulation 110-9 is used for tabulating quantities needed to fill and abandon a culvert.

R.C.B. culverts designated by the Preliminary Bridge Section, Soils Section, or others to be filled with flowable mortar are tabulated (Tabulation 110-9) and paid for as part of the flowable mortar bid item. Flowable mortar is considered incidental when the contractor elects to fill a R.C.B. rather than remove.  Holes that are drilled for the placement of flowable mortar in long or tall culverts will be incidental to the flowable mortar bid item.  The following notes should be included on the plans, depending on the amount of silt inside the culvert:

1. “Silt inside the existing culverts need not be removed prior to placing flowable mortar.”
2. “Do not apply Article 1109.14, C of the Standard Specifications to this item.” This note is to be used only when the amount of silt inside the culvert is not known.

If either the headwalls or all or part of a culvert are removed, Tabulation 110-2 needs to be included in the plans to denote this.

Chronology of Changes