PART 2 - PRODUCTS
2.1 MATERIALS AND CONSTRUCTION
A. Concrete and Reinforcement
1.
2.
Concrete used in construction of the structures shall be Class “AA” concrete.
Reinforcing steel bars shall be deformed new billet steel conforming to
ASTM A615, Grade 60. Wire fabric shall be cold drawn steel conforming to
ASTM A185.
B. Mortar: Mortar for manhole construction shall be sand-cement mortar
composed of one part Portland cement to two parts clean sand conforming to
ASTM C144.
C._‘Pre-cast Concrete Structures
1.
2.
3.
Pre-cast concrete structures shall consist of pre-cast reinforced concrete
sections conforming to the details as shown on the Drawings.
Pre-cast concrete sections shall be manufactured, tested and marked in
accordance with the latest provisions of ASTM C478.
The minimum 28-day compressive strength of the concrete for all sections
shall be 4,000 psi.
The maximum allowable absorption of the concrete shall not exceed eight
percent of the dry weight.
The circumferential reinforcement in the riser sections, conical top sections
and base wall sections shall consist of one line of steel and shall be not less
than 0.17 square inch per lineal foot.
The ends of each reinforced concrete manhole riser section and the bottom
end of the manhole top section shall be so formed that when the manhole
risers and the top are assembled, they will make a continuous and uniform
manhole.
Unless otherwise approved by ENGINEER, joints of the manhole sections
shall be of the tongue and groove type. Sections shall be joined using
rubber gaskets conforming to the applicable provisions of ASTM C443,
latest revision, or filled with an approved preformed plastic gasket meeting
the requirements of Federal Specifications SS-S-00210, “Sealing Compound,
Preformed Plastic for Pipe Joints,” Type 1, Rope Form.
Each section of the pre-cast structures shall have no more than two holes
for the purpose of handling and laying. These holes shall be tapered and
shall be plugged with rubber stoppers or mortar after installation.
D. Frames and Covers
1.
Manway frames, covers and grates shall be of the size and in the location
shown on the Drawings or equivalent approved by ENGINEER. Where
specified, the frame and cover shall be ductile iron, easily removable, and
equipped with handles.
File No. 3066.09
Pre-Cast Concrete Structures 03400 - 2 of 3 December 2017
