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5. Determine the volume of excavation for the storm sewer manhole MH 1. Given a 48" inside diameter manhole and 6" wall thickness, assume that the bottom of the trench is a 6.00 feet by 6.00 feet. Increase the depth by 1.5 feet from the top of casting to invert distance to determine overall trench depth. Again, assume that the soil is tough clay (0.25' Horizontal to 1.0' Vertical). MH1 depth=6
1. What is the depth of sewer for each of the following storm sewer segments? Sewer Run Sewer Depth Top of Casting Elevation Feet 911.50 Invert Elevation Feet Feet ΜΗ 1 905.50 CB 2 913.80 907.40 CB 3 916.30 910.10 CB 4 919.60 913.40 How toCB 5 922.10 916.00 6.1 Using the information from above, what is the average trench depth for each of the storm sewer segments from above? *Note: Increase the Sewer Depth from by 1.5 feet for trench depth and use top of casting (T.C.) for ground elevation. Sewer Run Average Trench Depth MH 1 to CB 2 7.7 CB 2 to CB 3 7.8 CB 3 to CB 4 ㅋㅋ CB 4 to CB 5 7.65 6 6.4 6.2 6.2
Sewer Run MH 1 to MH 2 MH 2 to MH 3 MH 3 to MH 4 MH 4 to MH 5 Bottom Width Feet 2 2 2 2 Top Width Feet 5.85 5.9 5-85 5.825 Average Width Feet 3.925 3.95 3.925 3.913
Given the production rate (BCY/Hour) from Item 3, the average trench depth from Item 1 and the average trench width from Item 2,, what is the estimated digging time per storm sewer segment? Sewer Run Segment Average Average Total Install Time Trench Trench Volume Length Feet Depth Feet Width Yd³ Hours Feet MH 1 to CB 2 270 7.7 3.925 362.225 2.21 CB 2 to CB 3 290 7.7 3.95 326-68 2.39 CB 3 to CB4 280 7.8 3.925 317.49 2.32 CB 4 to CB 5 7.65 3.913 288.26 2.1 260