CATEGORY 300 DRAINAGE SECTION 303 — PIPE CULVERTS
303.01 Description
Furnish and install pipe culverts, make connections to miscellaneous structures and other pipe culverts, reinstall existing pipes, remove existing pipe culverts, abandon existing pipes, and clean existing pipes.
303.02 Materials
No. 57 Aggregate 901.01 Crusher Run Aggregate CR-6 901.01 Curing Compound 902.07.03 Portland Cement Concrete 902.10, Mix No. 2 Grout 902.11 Controlled Low Strength Material 902.16 Brick 903.03 Mortar 903.06 Pipe Section 905 Select Borrow 916.01 Common Borrow 916.01 Stormwater Management (SWM) Facility Embankment Clay Core Borrow 916.01 Water 921.01 Detectable Utility Marking Tape 921.11 Bedding. Use earth meeting the requirements of M 145, A-1, A-2-4, A-2-5 or A-3. The maximum particle size is 1.25 in. Do not use organic material, stones larger than 1.5 in., or frozen lumps. Selected Backfill may be used. Backfill. Use material meeting the requirements for Select Borrow, Selected Backfill or Controlled Low Strength Material (Flowable Backfill). Large lumps, clods, frozen material, or rocks are not acceptable. For plastic pipe installations, use backfill materials meeting the requirements of M 145, A-1, A-2-4, A-2-5, or A-3. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS
303.03 Construction
303.03.01 Pipe Culvert Installation
When endwalls are visible from the roadway, construct them parallel to the roadway with the askew pipe protruding through the end wall. If not visible, construct them normal to the center line of the pipe. Clean existing pipes and dispose of the material. Trench Excavation. When a pipe is to be laid on existing ground, on or under fill, construct embankment to a height of at least 9 in., but not more than 3 ft above the proposed top of the pipe. Excavate to a depth at least 4 in. below the bottom of pipe. When rippable rock is encountered, remove rocks, boulders, and other hard, lumpy, or unyielding material to a depth of at least 12 in. below the bottom of the outer diameter of the pipe. When non-rippable rock is encountered, remove it to a depth of at least 8 in. below the outer diameter of the pipe. Handle excavated material as specified in 402.03.01. Ensure trench width is at least twice the outside diameter of the pipe or the outside diameter plus 18 in. on each side, whichever is less. Ensure trench sides are vertical up to at least the midpoint of the pipe to be installed.
a.Prepare Trench Subgrade. Fine grade and compact the subgrade to at least 97 percent of the maximum dry density according to T 180. Remove and dispose of all soft and unstable material and all other portions of the subgrade that will not properly compact as specified in Section 301. Replace with selected backfill and compact. Obtain subgrade approval as specified in 208.03.05.
b.Bedding. After preparing the trench subgrade, place pipe bedding backfill and compact. Ensure that the moisture content is in the range of optimum content to obtain thorough compaction. Place bedding for culverts that are 48 in. or more in nominal horizontal diameter in an approved foundation, shaped using a template that supports the pipe for at least 10 percent of its overall height. For pipe culverts installed in stormwater management (SWM) facility embankments, place pipe culverts on bedding matching the type and quality conforming to that specified for the surrounding fill material. Ensure pipe culverts are firmly and uniformly bedded throughout the entire length. Perform the work in the presence of the SWM facility As-Built (AB) Inspector.
c.Laying of Pipes. Lay pipes with hubs upgrade. A single lay hole through the shell of concrete pipe is acceptable with an approved lifting device. Ensure the lay hole is cast in the pipe during fabrication or core it without damaging or exposing any 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS reinforcement. After installation, permanently seal the lay hole by filling with mortar, rubber plug, or other approved means. Wood plugs may not be used. Lay holes that expose any reinforcement are not acceptable. Do not lay pipe in standing water or when weather conditions are deemed unsuitable by the Engineer.
d.Joints. Seal pipe joints in a manner appropriate for the applicable pipe material.
1.Reinforced Concrete Pipe. Seal circular pipe joints using rubber gaskets meeting C433. Seal elliptical pipe joints using preformed flexible joint sealants meeting C990.
2.Metal Pipe. Use bell and spigot joints with integral rubber gaskets or butt pipes and seal using rubber gaskets with an approved coupling band meeting 905.01.
3.Plastic Pipe. Use integral bell and spigot joints with flexible elastomeric seals meeting D3212.
e.Backfill. Ensure all joints have been sealed and are water-tight before placing backfill material. When pipe culverts are installed through SWM facility embankments, use material matching the type and quality conforming to that specified for the surrounding fill material. The presence of large lumps, clods, frozen material, or rocks in the backfill are unacceptable. Place backfill material along the side of the pipe for the full width of the trench in layers not exceeding an uncompacted depth of 6 in. Compact each layer simultaneously on both sides of the pipe using an approved mechanical tamper and as specified in Section 210. Compact thoroughly under the haunches of the pipe. Continue this method of filling and compacting until the compacted backfill material is at least 9 in. above the top of the pipe for concrete and metal pipe and at least 12 in. above the top of the pipe for plastic pipe. Prevent damage by heavy loads, equipment, and vehicular traffic. Replace any defective or damaged pipe. Where specified or directed, backfill using Flowable Backfill as specified in Section 314. For pipe culverts installed through SWM facility embankments with a clay core, place backfill around pipe culverts concurrently with clay core and embankment material adjacent to the pipe trench. Place backfill along the sides of the pipe in layers not exceeding an uncompacted depth of 4 in. Compact each layer simultaneously on both sides of the pipe and with core and embankment materials. Compact material around the pipe using hand tampers or approved mechanical tampers and ensure thorough compaction of material under pipe haunches. Continue this method of filling and compacting until the backfill is completed to at least 8 in. above the top of pipe. Perform the work in the presence of the SWM facility As-Built (AB) Inspector. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS Protect pipes from damage due to construction activities. Do not drive equipment within 4 ft when measured horizontally from the pipe nor drive equipment over the pipe until at least 24 in. of compacted fill is over the pipe. Place detectable utility marking tape in the trench immediately above the structural backfill. Demark the tape as to its purpose, i.e., "STORM DRAIN".
f.Inspection and Acceptance. Within 30 days following installation, and in the presence of the Engineer, visually inspect all pipe culverts. Any cracks, differential movement, efflorescence, rust stains, spalls, exposed reinforcement, slabbing, dents, buckling, holes, damaged coating, obstructions, improperly engaged joints, improper gasket placement, excessive joint gaps, misaligned joints, excessive deflection, or undue horizontal or vertical misalignment will be cause for repair or replacement. Video inspect pipe which cannot be physically accessed for inspection. Ensure that thermoplastic pipe deflection does not exceed 5 percent.
303.03.02 Mid-Pipe Pipe Culvert Connections. Pipe connections may be either prefabricated
or constructed in the field. Use a prefabricated connection unless specified or directed. For reinforced concrete pipes connecting to other reinforced concrete pipes, a field pipe connection includes cutting a hole in one pipe, inserting and trimming the connecting pipe, and placing a concrete collar using Concrete Mix No. 2 at the connection. Finish the connection to provide a smooth surface. For corrugated metal pipes, a welded connection may be substituted for the concrete collar when the connection is to other corrugated metal pipes. Coat the weld with a zinc rich paint coating according to M 36. For connections to drainage structures, refer to 305.03.05. For plastic pipes, use a prefabricated plastic connection matching the pipe material. When dissimilar pipe materials are encountered, use a junction box as specified in Section 305. 303.03.03 Pipe Culvert Encasement. When specified, encase pipes using Concrete Mix No. 2.
303.03.04 Removal of Existing Pipe Culverts. When specified, remove and dispose of existing
pipe culverts. Use backfill material that is similar to the adjacent material and compact as specified in Section 208, Section 210, or Section 701, whichever is applicable.
303.03.05 Reinstallation of Existing Pipe Culverts. When specified, remove, salvage, and
reinstall pipe culverts as specified in 303.03.01. 303.03.06 Abandoned Pipe Culverts. Plug abandoned pipe culverts using Concrete Mix No. 2 or brick masonry as specified in 463.03. Fill pipes with Flowable Backfill as specified in Section 314. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS
303.03.07 Clean Existing Pipe Culverts. When specified, clean existing pipe culverts, removing
all sediment and debris without damaging the pipe, pipe joints, or connecting structures. Remove and dispose of sediment and debris as specified in Section 308.
303.04 Measurement and Payment
The payment will be full compensation for all applicable excavation, sheeting, shoring, dewatering, hauling, storing, rehandling of material, removal and disposal of excess and unsuitable material, tamped fill, forming bed, foundation, grouting, masonry, bedding, pipe, backfill, compaction, inspection, and for all material, labor, equipment, tools, and incidentals necessary to complete the work.
303.04.01 New pipe culverts will be measured complete in place and paid for at the Contract unit
price per linear foot for the pertinent size and type of pipe. When a new pipe is installed in the same location as an existing pipe, the cost of removal and disposal of the existing pipe, including end walls and end sections, will not be measured but the cost will be incidental to the Contract price of new pipe. Detectable utility marking tape will not be measured but will be incidental to the Contract price of pertinent pipe item.
303.04.02 Pipe connections will be measured and paid for at the Contract unit price per each for
the pertinent size and type of pipe connection. No deduction from the new pipe measurement will be made for pipe connections. Connections to drainage structures with prefabricated holes in which the pipe will be connected with grout or mortar will not be measured, but the cost will be incidental to the pertinent pipe culvert item.
303.04.03 Pipe elbows will be measured and paid for at the Contract unit price per each for the
pertinent size and type of pipe elbow.
303.04.04 Excavation required below the planned elevation will be measured and paid for as
specified in 301.04.
303.04.05 Selected Backfill will be measured and paid for as specified in Section 302.04. 303.04.06 Flowable Backfill will be measured and paid for as specified in Section 314.04. 303.04.07 Select Borrow will be measured and paid for as specified in Section 203.04. 303.04.08 Common Borrow will be measured and paid for as specified in Section 203.04. 303.04.09 Pipe Bedding Backfill will be measured and paid for at the Contract unit price per cubic
yard.
303.04.10 Stormwater Management (SWM) Facility Embankment Clay Core Borrow will be
measured and paid for at the Contract unit price per cubic yard. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS
303.04.11 Pipe culvert encasement will be measured and paid for at the Contract unit price per
cubic yard of Mix 2 Concrete for Miscellaneous Structures.
303.04.12 Removal of Existing Pipe will be measured and paid for at the Contract unit price per
linear foot. The size and type of pipe will not be measured but will be incidental to the Contract unit price. Removal of existing end walls and existing end sections associated with the pipe will not be measured but the cost will be incidental to the Contract price.
303.04.13 Reinstallation of existing pipe culverts will be measured and paid for at the Contract
unit price per linear foot for Relaid Existing Pipe Culverts Any Size. The size and type of pipe will not be measured but will be incidental to the Contract price.
303.04.14 Abandoned pipe culverts will be measured and paid for at the Contract unit price per
cubic yard for Flowable Backfill for Pipe Abandonment.
303.04.15 Plugs for abandoned pipe culverts and plugs to create a permanent blockage of the flow
of water will be measured and paid for at the Contract unit price per cubic yard of Mix 2 Concrete for Miscellaneous Structures or Brick Masonry for Miscellaneous Structures.
303.04.16 Cleaning existing pipe culverts will be measured and paid for at the Contract unit price
per linear foot for Clean Existing Pipe Any Size. The size and type of pipe will not be measured but will be incidental to the Contract price. Removal of construction debris and sediment will not be measured for payment. 304 — STRUCTURAL PLATE PIPE AND STRUCTURAL PLATE PIPE ARCH CULVERTS CATEGORY 300 DRAINAGE SECTION 304 — STRUCTURAL PLATE PIPE AND STRUCTURAL PLATE PIPE ARCH CULVERTS
304.01 Description
Furnish and install structural plate pipe and structural plate pipe arch culverts.
304.02 Materials
No. 57 Aggregate 901.01 Crusher Run Aggregate CR-6 901.01 Curing Compound 902.07.03 Portland Cement Concrete 902.10, Mix No. 2 Structural Plate for Pipe and Pipe Arches Section 905 Detectable Utility Marking Tape 921.11
304.03 Construction
304.03.01 Fabrication. Submit working drawings, including erection diagrams and strutting
tables, for approval. Include proposed lengths and lifting locations of preassembled sections in the erection diagrams. Upon approval, shop fabricate the plates, including all required holes, to the required dimensions. Ship the plates complete, with proper markings and all necessary connection devices. Ensure the plate configurations have radii and curvature according to AASHTO Load and Resistance Factor Design (LRFD) Bridge Design Specifications. When bottom plates of circular pipes are specified to the thicker than top and side plates, cover at least 25 percent of the periphery of the circle with the thicker plate. For pipe arches, the thicker plates include corner plates as well as bottom plates. Lay these culverts on a firm bed, true to the specified line and grade. Along those edges of the plates that will form longitudinal seams in the finished structure, stagger bolt holes in rows 2 in. apart, with one row in the valley and one in the crest of the corrugations unless otherwise specified. Along those edges of the plates that will form circumferential seams in the finished structure, provide a bolt spacing of not more than 12 in. Ensure the diameter of the bolt holes in the longitudinal seams do not exceed the diameter of the bolt by more than 1/8 in. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS
Source: Maryland Standard Specifications for Construction and Materials, 2025 Edition. Pages 315–320 of 1,113.