874TEMPORARY RISER PIPE ASSEMBLY

874.1DESCRIPTION—This work is furnishing, placement, maintenance, and removal of a temporary riser

pipe assembly that functions as an outlet structure for a temporary sediment trap or sediment basin.

874.2MATERIAL—

• Pipe. Corrugated Metal Pipe, Section 601.2(a)4(d) for the size indicated.

• Welding Material. Steel Shapes. Section 1105.02(t)

• Reinforcement. Section 709.1

• Steel Shapes. Section 1105.02(a)2

• Welding Material. Steel Shapes. Section 1105.02(t). Reinforcement. AWS D1.4 Structural Welding Code, Reinforcing Steel.

874.3CONSTRUCTION—As shown on the Standard Drawings, as indicated, and as follows:

Fabricate riser and stub pipe as indicated. Fabricate trash rack and anti-vortex device as indicated. Excavate for temporary riser pipe assembly as required. Place concrete foundation and form bottom of riser pipe assembly with Class A Cement Concrete to channel the flow toward the outlet pipe as indicated. Join the riser pipe assembly to the outlet pipe using acceptable connections. Seal connection as specified in Section 601.3(d) and (i). Backfill using suitable embankment material. Attach trash rack to structure as indicated. Maintain as required or directed. When indicated or directed, remove temporary riser pipe assembly. Satisfactorily dispose of unsuitable and surplus material.

874.4MEASUREMENT AND PAYMENT—Each