NCEES Afternoon Q# 538 Retaining Wall Problem
Posted 10 April 2012 - 04:42 PM
Posted 10 April 2012 - 10:02 PM
Distribution 1 - (.5)(45)(4^2) = Resultant force of Triangle Distribution #1. To get the value of the bottom of the triangle do (45)(4) not squared. By doing squared you are basically finding the area in front of the distribution.
Distribution 2 - (4)(45)(9) = bottom of triangle distribution. Multiply this by the depth from the water table to the footing bottom (9) as shown bolded. This distribution is a rectangle and is the force of the soil above the water tables effect of foundation below. Again you are finding area in essence.
Distribution 3-(.5)(35)(9)^2 - This is a triangle distribution and is the effect of the saturated soil below the water table.
Distribution 4- (.5)(62.4)(9^2) - This is a triangle distribution of the water "pressure" so to say. For this step you usually do (Ka-1) not just Ka.
Sum these and there is your answer.
Dis 1 = 350 lb / ft
Dis 2 = 1620 lb/ ft
Dis 3 = 1417.5 lb/ft
Dis 4 = 2527.20 lb/ft
Sum = 5924.70lb/ft
Hope that helps and anyone correct me if I am wrong because I did this very fast and without checking it over too much. NCEES just lumps my Dis 3 and Dis 4 together.
Posted 16 October 2012 - 11:25 PM
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