Provide precast concrete boxes made of precast concrete sections in conformance with ASTM C913 and the following requirements.
(a) General.
(1) Precast boxes include:
a. Square/rectangular catch basin boxes and drop inlets.
b. Non-round manhole structure.
(2) Precast manufacturer shall have a professional engineer registered in the State of North Carolina on staff. Provide a certification signed and sealed by the North Carolina Professional Engineer that the boxes provided for the project are in conformance with the reference standards and these specifications and are structurally sufficient (i.e., adequate wall thickness and reinforcing). The boxes shall be adequate for the existing site conditions as described in the soils reports provided in these project specifications.
(3) Precast concrete boxes shall be manufactured by Adams Concrete, Carolina Precast Concrete, Inc., D & M Concrete Specialties, Inc, N. C. Products Corp., Stay Right Tank, Tindall Concrete Products, Inc. or approved substitute.
(b) Precast concrete sections.
(1) General. Concrete compressive strength shall be 4,000 psi minimum and rated for H-20 loading.
(2) Base. Cast monolithically without construction joints or with an approved PVC waterstop in the cold joint between the base slab and the walls. The width of the base extensions shall be no less than the base slab thickness and shall be as indicated on the details.
(3) Riser. Minimum lay length of 16-inches.
(4) Flat slab top. Designed for HS-20 traffic loadings as defined in ASTM C890. Items to be cast into special flat slap tops shall be sized to fit within the top and bottom surfaces. Provide a float finish for the exterior slab surface and a 1-inch chamfer on all exposed edges.
(5) Lifting devices. Devices for handling precast components shall be provided by the precast manufacturer and comply with OSHA Standard 1926.704.
(c) Joints.
(1) Manufactured in accordance with tolerance requirements of ASTM C 990 for butyl type joints.
(2) Minimize number of joints.
(3) Flexible joint sealants. Provide preformed butyl rubber based sealant material conforming to Federal Specification SS-S-210A, Type B - Butyl Rubber or O-ring rubber gasket conforming to ASTM C443.
(4) External seal. Provide a polyethylene backed flat butyl rubber sheet no less than 1/16-inch and 6-inches wide applied to outside perimeter of joint.
(d) Flexible pipe connectors. Provide flexible connectors for pipe to box that conform to ASTM C923.
(Ord. of 11-7-16, No. 10-16)