611 Pipe Culverts, Sewers, Drains, and Drainage Structures

Description (611.01)

This specification states requirements in terms of the required results and includes criteria for verifying compliance without stating the methods for achieving the required results.  The types of pipe are specified in accordance with their application and intended usage.  For a brief description of typical applications, refer to “Materials,” Section 611.02.  For a more detailed description, refer to the Location Design Manual, Volume 2, Drainage Design, and the plans.

The Inspector will monitor the materials and the installation plan. The Contractor will install the materials as well as monitor and document the installation while providing third party inspection/evaluation and certification of performance based on contract criteria.


Materials (611.02)

Materials selected as part of the installation plan will be inspected and approved by the Inspector prior to use.

Type A Conduits

Type A conduits are sealed culvert cross drains under pavements, paved shoulders, and embankments. These culvert cross drains are used to convey water from one side of the roadway to the other.  These culverts can be either smooth lined or corrugated.  Type A conduits are under pavement and open at both ends.

Type B Conduits

Type B conduits are storm sewers under pavement, paved shoulders, and commercial or industrial drives.  Storm sewers are used to convey water from one manhole or catch basin to the other. Storm sewers are always smooth lined.  Type B conduits have one or both ends closed with a drainage structure.

Type C Conduits

Type C conduits are storm sewers which are not under pavement, paved shoulders, or commercial and industrial drives.  Like Type B conduits, these conduits are connected to a manhole or catch basin and are always smooth lined.  Type C conduits have one or both ends closed with a drainage structure.

Type D Conduits

Type D conduits are culverts placed under residential driveways or bikeways. These conduits can be either smooth lined or corrugated. 

Type E Conduits

Type E conduits are farm drain headers in or outside the right-of-way or used for ditch elimination beyond the paved shoulder. These conduits can be either smooth lined or corrugated. 

Type F Conduits

Type F conduits are other miscellaneous pipe where a butt joint or a short length jointed pipe would be undesirable.  Outlets for underdrain or farm drains, house drain connections, pull box drains, or steep portions of a median outlet under an embankment are examples of Type F applications. These conduits can be either smooth lined or corrugated. 

Bedding and Backfill

The materials used for bedding and backfill are approved prior to use.  Installation will be in accordance with the Contractors accepted installation plan.

Low Strength Mortar Backfill (LSM)

In some cases, the plans designate the use of LSM as bedding and/or backfill material.  The requirements for LSM can be found in C&MS 613. There are three Types of mixes. Type 1 is a mixture of cement, fly ash, sand, and water.  The Type 2 mixture substitutes an entrained air additive for the fly ash. The Type 3 mixture is a mixture of fly ash and water. All three mixes may be used, or an alternative mix, submitted for approval by the Contractor, may be used if the plans do not call out a mix. The alternate mixes shall meet the criteria in C&MS 613.  Changes in the material type, amount, or sand gradation are allowed, as long as the final mix has the required strength, fills the voids, and sets up.


Submittals (611.04)

Shop Drawings and Calculations

The Project personnel will ensure Shop Drawings and calculations are sealed by a Registered Engineer as well as checked and properly sealed by a second Registered Engineer.

The Project personnel will ensure Load Rating calculations are submitted to the Office of Structural Engineering and a copy is filed in the project records.

The Project personnel will ensure Shop Drawings and calculations for Reinforced Concrete Circular Pipe, which require a special design, are submitted to the Office of Structural Engineering and a copy is filed in the project records.

The Project personnel will ensure Shop Drawings and calculations for Precast Reinforced Concrete three-sided flat topped culverts, precast reinforced concrete arch culverts, or precast reinforced concrete round sections, (706.051, 706.052, or 706.053) are submitted to the Office of Structural Engineering, and a copy is filed in the project records.

The Project personnel will ensure that if the Contractor substitutes one structure for another, they also submit hydraulic calculations to the Office of Hydraulic Engineering.

Installation Plan

Each size and type of conduit (A, B, C, D, E, F, etc.) to be installed will require a written installation plan along with written confirmation from the conduit manufacturer. Project personnel will review and accept the installation plan if it includes all the requirements listed in 611.04.B:

1.   Trench and excavation cross-sections with dimensions.

2.   Locations where the conduit is installed in a cut situation and where it is installed in a fill situation.

3.   Type of bedding and backfill material used and maximum lift thickness.

4.   Compaction density requirements for bedding and backfill and compaction equipment.

5.   Identify the starting location (outlet or inlet) for each run of conduit. All conduit must be laid from the outlet to the inlet unless approved by the Engineer.  Bell or groove-end Type A conduit must have a bell or groove-end at the inlet.

6.   Maximum allowable joint gap between conduit sections.

7.   Other installation details, as necessary.

8.   Written confirmation from the conduit manufacturer that the pipe material and strength supplied are appropriate for the material and density requirements described in the installation plan for the backfill and bedding as well as the height of cover. Ensure the pipe material meets the durability design specified in the plans.  This confirmation by the conduit manufacturer will not relieve the Contractor of the responsibility for obtaining the required results.

The Project personnel will monitor the installation process to ensure compliance with the installation plan.  Each installation plan should be filed in the project records in the appropriate reference file.

For further detail on the Material Certification Program, contact the District Testing Engineer or refer to Materials Management Sampling and Testing Program Manual.

Construction Inspection

Each day the Contractor will submit to the Project personnel a properly completed construction inspection form, CA-P-1, for conduit and form, CA-P-3, for drainage structures.  The project personnel will review the forms to ensure the information on the construction inspection form is complete and accurate. The forms should document the installation procedure described in the accepted installation plan. 

The forms should include trench and bedding measurements every 50 feet with a minimum of two per run.  Measurements should be recorded to the nearest 0.1 foot (30 mm). 

All items regarding the conduits and drainage structure should be included on the daily inspection reports, including:

1.   Pipe joint sealer application.

2.   Coupling band installation.

3.   Field paving of conduits, materials, and installation process.

4.   Concrete curing applied.

5.   Waterproofing materials and installation process.

Performance Report

The Performance Report will consist of a performance inspection, a performance survey, a surface settlement evaluation, and an independent evaluation.

The Project personnel will witness the performance inspection, as performed by the Contractor. The conduits and structures should be cleaned of all debris to allow for proper inspection. The performance inspection should be 30 days after all cover up to the final grade or aggregate base has been completed, but should be completed before any pavement is placed. 

A performance inspection report will be created for each conduit size (greater than or equal to 12 inches) and material type. The report will include the following information:

1.   Project number and County-Route-Section.

2.   Date of performance inspection.

3.   Type and size of conduit.

4.   Conduit diameter report from the manufacturer.

5.   Time of video recording.

6.   Location (e.g., station and offset) and viewing direction.  For Type A and B conduit, include the latitude and longitude of the conduit at the location where the culvert centerline and the roadway centerline intersect. Ensure the units are in decimal degrees to the sixth decimal place. Use a Global Navigation Satellite System (GNSS) unit that is accurate to within 15 feet (4.5 meters).

7.   Summary of all defects, including type, measurement, and location.

8.   For remote inspections using a mandrel, indicate in the performance report, the size of the mandrel and how it was calculated.  Document all locations where the mandrel was unable to advance through the conduit.

9.   For remote inspections using a crawler mounted camera with laser profiler, include:

      a.   Three dimensional model of the conduit based on the laser profile measurements.

      b.   Digital profile of conduit extracted from the inspection video.

      c.   Calculations of the ovality, capacity, and delta of the conduit.

      d.   Explanation as to why data was unattainable for any section of the conduit.

Description: Description: Description: 1-s2_0-S0886779810000970-gr4   Description: Description: Description: Large-open-joint

Figure 611.A – Internal Conduit

(a) Defective and open joint – VC pipe, (b) Defective connection – VC pipe, (c) Perfect connection – VC pipe, and (d) Exposed reinforcement – RC pipe.


Description: Description: Description: Culvert_cat-372

Figure 611.B – You Never Know What you Will Find


Figure 611.C – Sample Pipe Inspection Report including Ovality Observations


Description: Description: Description: Deflection_Gauges

Figure 611.D – Example Mandrel Gauges



A performance survey will document the elevations and locations of each Type A, B, and C conduit and drainage structure to determine conformity with the Contract Documents (Plans). 

An evaluation of surface settlements within 4 feet of the trench limits or drainage structure will be created by an independent registered engineer and submitted to the Project personnel.

After the performance inspection, a survey and settlement evaluation is completed, and an independent registered engineer will provide a review of the conduits and structures. This independent registered engineer will provide a statement indicating that no repairs are required, or that repairs are required, and the repair plan meets the design requirements.


Documentation Requirements - 611 Pipe Culverts, Sewers, Drains and Drainage Structures

1.   File the Contractor supplied Shop Drawings with each applicable reference.

2.   File the Contractor supplied Installation Plan in the project records with each applicable reference.

3.   File Contractor supplied form CA-P-1 or CA-P-3 as appropriate in the project records with each applicable reference.  Make sure all waterproofing and field paving is noted in the comments section of the forms.

4.   Enter the daily amounts installed into SiteManager as appropriate.

5.   File the Contractor supplied Performance Inspection, Performance Survey, and Surface Settlement Evaluation in the project records with each applicable reference.

6.   File the Conduit Evaluation and Drainage Structure Evaluation as provided by an independent registered engineer in the project records with each appropriate reference.