Ind. Admin. Code tit. 105, r. 16.5-1-9 – Trenching

Sec. 9. (a) In a common open trench, the ITS conduit is colored orange, blue, and green and placed first at the bottom of the trench. The limited access highway conduit is colored red, black, white, and grey and placed above the ITS conduit. If there is space available in the trench, an operator may place conduit in the trench, and the conduit is colored terracotta or purple.

(b) Conduit may be trenched or plowed at the operator's discretion and as allowed by the site conditions.

(c) Flexible roadside delineators disturbed during trenching operations must be restored or replaced at no additional cost to the department.

(d) The conduit type, number, and size must be shown on the permit plans.

(e) Hand trenching is required in areas where sensitive existing crossing utilities or broadband have been identified and will likely require positive identification of the existing utility or broadband before trenching above or below the existing utility line, or where surface features, such as riprap, inhibits trenching. The method of positive identification of the existing utility line is at the discretion of the operator and accomplished at no additional cost to the department. Any material that is removed to accomplish hand trenching shall be restored or replaced in kind by the operator at no additional cost to the department.

(f) Conduit may be installed by directional drilling at locations specified as hand trenched or offset trench on the permit plans at no additional cost to the department.

(g) Offset trench is required in areas where the trench is located behind obstructions. This type of trenching uses a long reach hydraulic driven trenching machine to reach over and beyond the obstruction to finish the trench.

(h) Trenches, bedding, and backfill must comply with this subsection as follows:

(1) Trenches must be cut with vertical faces where soil and depth conditions allow. The width of a trench must be the minimum necessary to accomplish the installation. Shoring must be used when necessary, under Occupation [sic, Occupational] Safety and Health Administration requirements.
(2) Bedding must be provided to a depth of six (6) inches or fifty percent (50%) of the nominal diameter of the pipe, duct, or duct bank, whichever is less. Bedding is not required for pipes, ducts, or duct banks encased in concrete or flowable fill. The bottom of the trench must be prepared to provide the pipe, duct, or duct bank with uniform bedding support throughout the length of the installation.
(3) Backfill must be provided under the INDOT Standard Specifications, Section 715.09*, effective September 1, 2024.

*This document is incorporated by reference. Copies of the 2024 Standard Specifications can be found at https://www.in.gov/dot/div/contracts/standards/book/sep23/sep.htm or may be obtained at the Indiana Department of Transportation, 100 North Senate Avenue, Room N730, Indianapolis, IN 46204.

(Indiana Department of Transportation; 105 IAC 16.5-1-9; filed Jun 20, 2025, 1:31 p.m.: 20250716-IR-105250150FRA)