FLOOD00281

• County: Larimer
• Community: Greeley
• Title: Design Criteria and Construction Specifications volume 2 of 5 Storm Drainage Criteria
• Date: 10/1/1997
• Prepared For: Greeley
• Prepared By: Department of Public Works
• Floodplain - Doc Type: Educational/Technical/Reference Information

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2.

Concrete side slopes shall be extended to include the
freeboard height.

b. Super-elevation - Super-elevation of the water surface
shall be determined at all horizontal curves, and design
of the channel section adjusted accordingly.

c. Velocities - Flow velocities shall be such that critical
or super critical flow conditions are not created. In no
case shall the velocity exceed 18 fps.

Concrete Materials (Small Drainageway)

a. Cement type: Sulphate resistant.

b. Minimum cement content: 550 lbs/CY

c. Maximum water content: 0.50 (six gallons per sack)

d. Maximum aggregate size: l~ inches

e. Air content range: 4% to 7%

f. Slump: 2 to 4 inches
g. Minimum compressive strength (fIe): 3,750 psi @ 28 days

3.

Concrete Lining section (Small Drainageway)

a. All concrete lining shall have a sufficient thickness to
withstand the structural and hydraulic loads.

b. The side slopes shall be a maximum of 2 vertical to 1
horizontal, or be designed as a structurally reinforced
retaining wall, if steeper.

4.

Concrete Joints (Small Drainageway)

a. Expansion joints shall be installed where new concrete
lining is connected to a rigid structure or to existing
concrete lining which is not continuously reinforced.

b. Longitudinal joints, where required, shall be constructed
on the side walls at least one foot vertically above the
channel invert.

c. All joints shall be designed to prevent differential
movement.

d. Construction joints are required for all cold joints and
where the lining thickness changes.

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