2506Manholes and Catch Basins

2506.1DESCRIPTION

This Work consists of constructing or reconstructing brick or concrete block masonry, cast-in-place concrete, precast sectional concrete, or pipe Structures for access and drainage into underground drainage or other systems.

For the purpose of the Work specified in section 2506, “Manholes and Catch Basins,” the Department defines precast concrete median drains as casting assemblies.

2506.2MATERIALS

Use 3G52 concrete. B Mortar Use 3W8X concrete.

2506.3CONSTRUCTION REQUIREMENTS

A General A.1 Combination Construction The Engineer may allow a combination of cast-in-place and prefabricated concrete construction, if the Contract does not specify the type of construction for a Structure and if the Contractor maintains the structural strength and continuity. A.2 Intercepting Existing Facilities Where the new Structure will intercept an existing underground facility, incorporate the existing facility into the new Structure to the extent required, including any necessary removal, replacement, or special connections, without detriment to the planned function of the facility.

A.3 Abandoned Pipes When abandoning a pipe that enters a Structure that will not be abandoned, detach the pipe from the Structure wall and permanently plug the wall opening and the upgrade end of the abandoned pipe with concrete or masonry. A.4 Excavation, Bedding, and Backfill Excavate, bed, and backfill in accordance with 2451, “Structure Excavations and Backfills.” A.5 Inspection Before Construction Do not place mortar in any unit or section of Work before the Engineer has inspected and approved the foundation preparations, Materials, and provisions for cold weather protection. A.6 Temperature Restrictions Do not place mortar on a frozen foundation or against any surface with a temperature below freezing. Do not start or continue production of concrete or mortar when the ambient air temperature at the construction site, away from artificial heat, is less than 36 °F. The Engineer may otherwise approve in accordance to any of the following:

approved by the Engineer Do not use masonry units or Aggregate in temperatures 32°F or less, except as directed by the Engineer. Maintain concrete and mortar mixes at a temperature from 50°F to 90°F until incorporated into the Work. The Engineer may approve heating of masonry units, mix Materials, or mortar. Do not spot heat these Materials using steam jets or direct application of combustion heating devices as the Work progresses. B Cast-in-Place Concrete Install cast-in-place Structures in accordance with 2411, “Minor Concrete Structures,” and the Plans. C Masonry Provide masonry in accordance with the requirements in this section if at least part of the Structure is constructed using clay brick or concrete masonry units. For the purpose of the Work specified in 2506, “Manholes and Catch Basins,” The Department defines “unit” as the brick or concrete block unless otherwise qualified in this section. Do not moisten concrete masonry Units before placement in the Work. Moisten all other types of masonry Units before placement. Place Units in a full mortar bed, in horizontal courses, using the “shove joint” method, as described in this section. Fill joints with mortar. Strike joints on the inside of the Structure, providing a joint width no greater than 0.5 inch wide. Plaster the outside of the Structure with mortar to a smooth surface.

Install steps, pipes, or other fixtures required by the Contract, as the Work progresses. Fit the Units around pipes that penetrate the Structure, using only part of the unit to form a neat juncture at the pipe as approved by the Engineer. Bond attachments to the Structure using mortar to fill voids. For manholes or catch basins constructed of brick, meet the following additional requirements:

inside of the Structure. Where the thickness of the wall is greater than the length of one brick, the Contractor may lay the outside bricks circumferentially using full header construction in at least each sixth course.

header construction in at least each sixth course. Do not use bats or spalls except for shaping around openings or for finishing out a course. When shaping around openings or finishing out a course, place full bricks in the corners and the bats in the interior of the course. Ensure the least dimension of the exposed faces of bats is at least 50 percent of the width of a brick. When using the alternate method of constructing the tapered portion of a manhole with concrete block as shown on the Plans, use concrete units specifically shaped to transition between the vertical and the sloped walls. D Sectional Concrete Set the bottom pre-cast section in a full mortar bed and fill the joints between sections and around pipes with mortar or a plastic cementing compound approved by the Engineer. Install cover for a 4020 Structure on a full mortar bed according to Standard Plate 4020. E Pipe Construct metal or concrete pipe manholes as shown on the Plans. F Castings Set the frame or ring castings to the designated elevation on a full mortar bed . If using metal pipe construction, set casting as shown on the Plans, as specified in the Specifications, or as approved by the Engineer. Place a 4 inch thick concrete encasement around the outside of the manhole or catch basin as detailed in Standard Plate 4026. Place this encasement at the time of final casting placement. If the Plans show castings not bonded to the manhole or catch basin, finish the mortar bed to the required grade and allow the mortar bed to set. After the mortar bed sets, apply a lubricant approved by the Engineer to the bed and install the casting. G Adjusting Frame or Ring Castings Provide vertical adjustment of access castings made to the planned elevation on the Structure. Meet the criteria that full support for the casting is obtained above the cone section. Limit thickness of each adjusting ring to 6 inches or less. Encase adjusting rings in mortar according to the Plan. Construct new structures so the height above the cone does not exceed 9 inches, including mortar but not including the frame. Use no more than 2 adjusting rings. Reconstruct in-place structures so the height above the cone does not exceed 12 inches, including mortar but not including the frame. Use no more than 3 adjusting rings. If these criteria cannot be met by vertical adjusting Work, reconstruct the Structure.

For upward adjustment of castings, the Contractor may use any of the Structure Materials or applicable construction methods specified in this subsection, provided they are compatible with the in- place construction. The Contractor may use auxiliary ring castings and adjusting rings as shown on the Plans. H Reconstructing In-Place Structures If the Plans require reconstructing the manhole or catch basin or if raising or lowering the frame or ring casting beyond the limits specified in 2506.3G, “Adjusting Frame or Ring Castings,” reconstruct the Structure as shown on the Plans or directed by the Engineer. Perform reconstruction consistent with the type of construction used for the in- place Structure meeting the requirements specified in this section for new construction . The Contractor may use salvaged Material, if approved by the Engineer. Thoroughly bond new Work to the in-place Structure. I Backfilling If the Structure consists of cast-in-place concrete or of bricks or blocks laid in mortar, do not place the backfill until the concrete or mortar has cured for at least 3 Calendar Days. Excavated Materials not required for backfill shall become the property of the Contractor . Dispose of the excavated Material off the Right-of-way in accordance with 2106, “Excavation and Embankment – Compacted Volume Method,” at no additional cost to the Department. J Cleaning Clean sediment and debris from manholes and catch basins before final acceptance.

2506.4METHOD OF MEASUREMENT

The Engineer will measure manholes and catch basins as drainageS tructures. A Constructing Drainage Structures If the Plans specify measurement by length for vertical Structures constructed on a concrete base, the Engineer will measure the height as the difference in elevation between the bottom of the casting and the invert elevation of the outlet pipe, plus an allowance of 0.70 feet for the depth of the concrete base, regardless of its actual thickness. If the Plans specify measurement by length for pipe Structures designed with a “tee” section in the sewer or Culvert line, the Engineer will measure the length as the difference in elevation between the bottom of the casting and the flow line elevation of the sewer or Culvert pipe for vertical construction, or as shown in the Plans for other special designs not constructed vertically. The Engineer will measure the “run” of the pipe structure “tee” section as Culvert or sewer pipe. If the Plans specify the measurement of each Structure complete in-place, the Engineer will separately measure drainage Structures of each design as individual units complete in place, including any castings provided and installed. B Reconstruction The Engineer will measure reconstruction to the nearest 0.1 feet, of the height from the bottom of the reconstructed portion to the bottom of the newly set casting, regardless of type. C Castings The Engineer will measure casting assembly by the number of casting assemblies provided and installed. The Engineer will measure install casting by the number of castings installed.

The Engineer will not measure castings for Structures measured as a Unit. The Engineer will consider all castings required for an individual Structure as one assembly. D Adjusting Castings The Engineer will measure adjusting castings by the number of casting assemblies adjusted. The Engineer will consider all castings required for an individual Structure as one assembly.

2506.5BASIS OF PAYMENT

The Contract Unit Price for constructing or reconstructing drainage Structures includes all costs for completing the Work, including the cost of excavation, except for the cost of specific Contract Items, in accordance with the following:

detached rocks with a volume greater than 0.5 cubic yard as Extra Work in accordance with 1402, “Contract Revisions,” unless the existence of the rock is shown on the Plans.

removing the existing casting, but does not include placement of a casting on the reconstructed Structure.

removing and replacing all or a portion of the Structure as shown on the Plans, adjacent pavement Aggregate base, and excavation if, except for the Structure construction, the surface would not otherwise have been disturbed. The Department will pay for the cost of this Work at the Contract Unit Price based on the area to the nearest 0.1 square yard within a rectangle with sides that lie 1.5 feet outside the Structure limits. The Department will include the cost of removing and replacing pavement outside of these limits or for replacing any other type of surfacing with other applicable P ay Items.

individual units complete in-place includes the cost of providing and installing any castings required.

removing and replacing concrete surfacing in connection with the item of adjust frame and ring castings.

final casting placement, with no additional cost to the Department.

accordance with 2451.5, “Structure Excavations and Backfills, Basis of Payment.”

and installing the in-place casting; removing deteriorated rings; and providing and installing all sewer blocks, bricks, rings and grout necessary to raise or lower in -place castings to the elevation shown on the Plans or directed by the Engineer. The Department will pay for manholes and catch basins as drainage Structures on the basis of the following schedule: Item No. Item Unit

2506.502 Construct Drainage Structure Design ___ each

2 Casting Assembly each

2 Install Casting each

2 Adjust Frame and Ring Casting each

3 Construct Drainage Structure Design ___ linear foot

3 Reconstruct Drainage Structure linear foot