SEWER MANHOLE ACCESSORIES:
A. Gasket materials shall be top grade (100% solids, vulcanized) butyl rubber and shall meet or
exceed AASHTO M-198.
B. Couplings at the manhole-pipe interface shall be made with a rubber seal system (with or
without stainless steel straps) meeting the requirements of ASTM C923 and recommended
for this type of connection.
C. — Stubs installed as specified and indicated on the drawings shall be short pieces of the same
class pipe as that entering the manhole and shall have either stoppers or end caps as shown on
the drawings. Stoppers or end caps shall be especially designed for that application.
PART 3 - EXECUTION
3.01 INSTALLATION:
A. PRECAST SECTIONS:
1. Precast bases shall be supported on a compacted level foundation of crushed stone, as
specified in Section 02300 EARTHWORK, at least 6-inches thick, but shall vary to
the depth necessary to reach sound undisturbed earth.
2. Precast reinforced concrete sections shall be set vertical and with sections in true
alignment.
3. Butyl rubber joint sealant shall be installed between each concrete section.
4. All holes in sections used for handling the sections shall be thoroughly plugged with
mortar. Mortar shall be one part cement to 1-1/2 parts sand, mixed slightly damp to
the touch (just short of "balling"), hammered into the holes until it is dense and an
excess of paste appears on the surface, and then finished smooth and flush with the
adjoining surfaces.
B. BRICK WORK:
1. _ Bricks shall be moistened by suitable means, as directed, until they are neither so dry
as to absorb water from the mortar nor so wet as to be slippery when laid.
2. Each brick shall be laid as a header in a full bed and joint of mortar without requiring
subsequent grouting, flushing or filling, and shall be thoroughly bonded as directed.
3. The brick inverts shall conform accurately to the size of the adjoining pipes. Side
inverts shall be curved and main inverts (where direction changes) shall be laid out in
smooth curves of the longest possible radius which is tangent to the centerlines of
adjoining pipe.
2019 CIPP Lining Project Precast Manholes
Nashua, NH 02631-5
