Johnson House Excavation & Drainage Lab Assignment (1) Calculate the total volume of topsoil stripped from the site according to the specifications. (2) Calculate the finished floor (FF) elevation using the drawings and specifications. This will be used in later labs. Follow these steps (a) Using the contour drawing (sheet no. A1), find the elevations at the four corners of the house before excavation. Assume that the slope across the site is constant, i.e. assume the third contour (elevation 407 below and to the left) is approximately the same distance away from 407.5 as the 408 contour. Don't forget to take into account that 6" of topsoil is to be stripped. (b) Determine the highest elevation of the four corners of the house. (c) To that highest elevation, add the minimum 24” clearance to establish the elevation of the bottom of the joists (TJI). (d) From the dimensions given in detail 7, sheet no. A8, determine the FF elevation. (3) Calculate the excavation volume for the perimeter footing. There is no basement and there is no excavation for the whole house. The existing ground is going to stay in place, except for the 6" of topsoil that is to be stripped. Follow these steps (a) Using the elevations obtained from 2(a) above, determine the average elevation of the four corners of the house after the topsoil has been stripped. This is used in determining the depth of excavation. (b) Using the lowest corner elevation and the dimensions of the footing, find the elevation of the bottom of the footing. Remember from the specifications that a minimum 18” of cover has to be maintained about the top of the footing. Refer to detail 7, sheet no. A8 for footing dimensions. (c) Subtract the elevation of the bottom of the footing from the average elevation of the 4 corners. This is the depth of excavation. (d) Determine the perimeter length of the centerline of the walls. (e) Using the cross sectional area of the trench, determine the volume of excavation. (4) Determine the volume of backfill for the Perimeter Footing. Subtract the volume that the footing and wall will take up from the amount of excavated material. (5) Calculate the length of drainage pipe needed in feet. (6) Calculate the volume of drainage gravel needed in cubic yards. (7) Estimate the amount of surplus topsoil and excavated material that will need to be disposed of (cubic yards). Assume that topsoil will be 6" deep and it will only be used for the 10 ft. that the grade is to slope away from the house at 5%.