207Culvert Excavation and Trench Excavation

207.01 Description

This work is the excavation for placing or removing drainage and other appurtenant structures. It includes foundation preparation, backfilling, disposal of excavation material, bailing, drainage, sheeting, shoring, cribbing and installation of safety measures needed to satisfy the requirements of Subsection 107.17. Excavation classes are described below.

207.01.1 Culvert Excavation

Culvert excavation is all work under Subsection 207.01, where vertical walls are not required, and the excavation width is not specified.

207.01.2 Trench Excavation

Trench excavation is the excavation for placing or removing storm drains, sanitary sewers, water lines, and other installations in the contract. Vertical trench walls, when required, must be shored, or supported to meet the U.S. Department of Labor, OSHA, Safety and Health Regulations for Construction. Trench widths are specified in Subsection 207.03.3 .

207.02 Reserved

207.03 Construction Requirements

207.03.1 General

Excavate to permit removal, jointing, and backfilling of pipe. Construct and maintain the excavations to prevent personal injuries, damage to foundations, structures, pole lines, or other facilities. Pile and maintain all excavated material to meet OSHA requirements and with a minimum of inconvenience to the public. Do not obstruct fire hydrants, water valves, meters, and the free flow of storm water in gutters, other conduits, and natural water courses. Do not excavate below the specified depth, except as permitted in Subsection 207.03.6 . Remove all obstructions in the excavation at Contractor expense. Backfill excavated areas in accordance with Subsection 603.03.4. Do not place backfill against newly constructed masonry or concrete structures for at least 14 calendar days. Remove all sheeting and bracing before backfilling.

207.03.2 Culvert Excavation

When special foundation stabilization is specified, excavate the bedding trench walls vertically and excavate the trench width to provide room for the bedding material.

207.03.3 Trench Excavation

Keep trench lengths to a minimum in paved roadways, sidewalks, or other improved areas, in advance of the pipe laying and not to exceed 200 feet (61 m). Keep trench backfilling and compaction to within 300 feet (91.5 m) of the installed pipe. Cut the pavement full depth vertically along regular neat lines in paved roadways that require patching. Excavate the minimum trench width possible. When vertical trench walls are specified, the maximum trench width is the external width of the pipe barrel plus 3 feet (915 mm). When a special foundation is specified, excavate the bedding trench walls vertically and the trench width as specified. Do not exceed the specified trench width without the Project Manager’s approval when vertical trench walls are specified. 207 – CULVERT EXCAVATION 2020 EDITION V5.1 AND TRENCH EXCAVATION 207-2 Furnish any additional select backfill material and additional surface and subsurface improvements if the maximum trench width is exceeded at Contractor expense.

207.03.4 Excavation for Appurtenant Structures

Excavate for riprap, rubble masonry, retaining walls, cutoff walls, headwalls, manholes, drop inlets, catch basins, headgates, division boxes, and other structures appurtenant to culverts, sewers, drains, pipes, or tubing to meet the applicable requirements of Subsection 207.03.1.

207.03.5 Shoring

Provide and remove shoring or supports for excavation walls that protect the work, existing property, utilities, pavement, and other existing facilities. Provide safe working conditions meeting OSHA, local and state safety codes. Repair damage caused from excavation support failure or from failure to provide support at Contractor expense.

207.03.6 Foundation Preparation

Compact foundations for culverts, sewers, drains, pipes, tubing, and appurtenant structures to the moisture and density requirements of Subsection 203.03.3 . Remove unstable or unsuitable material encountered below the excavation floor elevation and replace with material meeting Subsection 701.04.2. Cover with bedding material meeting Subsection 701.04.1 as directed. If approved by the Project Manager excavatable CLSM may be substituted as bedding material for concrete and steel pipes. A request to use excavatable CLSM for any other pipes or application must be submitted at least 5 business days prior to use. The Project Manager will investigate unstable pipe installations requiring 4 feet (1.2 m) or more of foundation material. Remove unyielding material below the staked elevation to at least 12 inches (305 mm) and replace with bedding material meeting Subsection 701.04. Bed culverts larger than 12 inches (305 mm) as shown in the Detailed Drawings. Place bedding for 12-inch (305 mm) diameter and smaller culverts to uniformly support the culvert throughout its length. The bedding does not need to conform to the outside of the culvert. Do not lay pipe until the foundations are approved by the Project Manager. Remove and relay pipe laid on unapproved foundations at Contractor expense.

207.04 Method of Measurement

Culvert excavation, trench excavation and excavation for bedding and foundation material are not measured for payment.

207.05 Basis of Payment

Payment for all costs associated with culvert and trench excavation, furnishing, and installing culverts is included in the contract unit price per foot (m) of pipe (type and size). When bedding or foundation material is specified in the contract, payment for all costs associated with excavation required to place bedding and foundation material is included in the contract unit price per cubic yard (m