Document - 2.pdf

9 % of the dry mass for Test Method A procedure or 8.5 % for

Test Method B procedure. All specimens shall be free of visible

cracks and shall represent the full thickness of the product.

8.2.2.2 Specimens for Test Method B shall meet the require-

ments of Test Methods

C497

8.2.2.3 Each specimen tested by Test Method A shall have a

minimum mass of 1.0 kg.

8.2.2.4 When the initial absorption specimen from a con-

crete product fails to conform to this specification, the absorp-

tion test shall be made on another specimen from the same

product and the results of the retest shall be substituted for the

original test results.

8.2.3

Retests—

When not more than 20 % of the concrete

test specimens tested under either

8.2.2.1

8.2.2.2

fail to pass

the requirements of this specification, the manufacturer is not

prohibited from culling his stock and eliminating whatever

quantity of product he desires and shall so mark the culled

product that they will not be shipped for the order. The required

tests shall be made on the balance of the order and the products

shall be accepted if in conformance with the requirements of

this specification.

8.3

Test Equipment—

Every manufacturer furnishing man-

hole products under this specification shall furnish all facilities

and personnel necessary to carry out the tests required for

acceptance.

9. Repairs

9.1 Repair of manhole products shall not be prohibited, if

necessary, because of imperfections in manufacture or damage

during handling, and will be acceptable if, in the opinion of the

owner, the repaired products conform to the requirements of

this specification.

10. Inspection

10.1 The quality of materials, the process of manufacture,

and the finished manhole products shall be subject to inspec-

tion and approval by the owner.

11. Product Marking

11.1 The following information shall be legibly marked on

each precast concrete product:

11.1.1 Specification and product designation: MH for man-

hole base, riser, conical tops, and grade rings,

11.1.2 Date of manufacture, and

11.1.3 Name or trademark of the manufacturer.

11.2 Marking shall be indented into the concrete or shall be

painted thereon with waterproof paint.

PART II—PRODUCTS

12. Grade Rings

12.1

Scope—

This section covers precast reinforced concrete

grade rings used for final adjustment of manholes to grade.

12.2

Acceptance—

Acceptability of grade rings covered by

this specification shall be determined by the results of such

tests of materials as are required by Section

; by compressive

strength tests on concrete cores or concrete cylinders required

by Section

; and by inspection of the finished product,

including amount and placement of reinforcement as pre-

scribed by

12.4

12.5

and

12.6

, to determine its conformance

with the design prescribed under this specification and its

freedom from defects.

12.3

Design—

The minimum wall thickness shall be one

twelfth of the internal diameter of the grade ring or 100 mm,

whichever is greater.

12.3.1

Joints—

Grade rings are not required to have the joint

formed with male and female ends.

12.4

Circumferential Reinforcement:

12.4.1 The circumferential reinforcement shall have an

equivalent area of not less than 150 mm

/vertical m, but not

less than 15 mm

in any one grade ring.

12.4.2 The circumferential reinforcement shall be one line

in the center third of the wall of the grade ring.

12.5

Permissible Variations:

12.5.1

Internal Diameter—

The internal diameter of grade

rings shall not vary more than

1 %.

12.5.2

Wall Thickness—

The wall thickness of grade rings

shall be not less than that prescribed in the design by more than

5 % or

5 mm, whichever is greater. A wall thickness greater

than that prescribed in the design shall not be cause for

rejection.

12.5.3

Height of Two Opposite Sides—

Variations in laying

heights of two opposite sides of grade rings shall be not more

than 6 mm.

12.5.4

Height of Grade Ring—

The underrun in height of a

grade ring shall be not more than 20 mm/m of height.

12.5.5

Position of Reinforcement—

For grade rings with a

100-mm wall thickness, the maximum variation in the design

position of circumferential reinforcement from that described

12.4.1

shall be

10 % of the wall thickness or

6 mm,

whichever is greater. For grade rings with a wall thickness

greater than 100-mm, the maximum variation from the design

position of reinforcement shall be

10 % of the wall thickness

16 mm, whichever is the lesser. In no case, however, shall

the cover over the reinforcement be less than 19 mm. The

preceding minimum cover limitation does not apply to the

mating surfaces of the joint.

12.5.6

Area of Reinforcement—

Steel reinforcement areas

that are 10 mm

/linear m less than called for by design shall be

considered as meeting the required steel reinforcement area.

12.6

Rejection

12.6.1 Grade rings shall be subject to rejection for failure to

conform to any of the specification requirements. In addition,

an individual grade ring shall be subject to rejection because of

any of the following:

12.6.1.1 Fractures or cracks passing through the wall, ex-

cept for a single end crack that does not exceed the depth of the

joint.

12.6.1.2 Defects that indicate mixing and molding not in

compliance with

7.1

or surface defects indicating honey-

combed or open texture that would adversely affect the

function of the grade ring.

C478M − 15

Downloaded/printed by

Jed Friesen (Predl Systems) pursuant to License Agreement. No further reproductions authorized.