1. You are driving a large number of one-foot square precast concrete piles at a site. Prior to going out to the site to

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1 You Are Driving A Large Number Of One Foot Square Precast Concrete Piles At A Site Prior To Going Out To The Site To 1 (73.66 KiB) Viewed 34 times

1. You are driving a large number of one-foot square precast concrete piles at a site. Prior to going out to the site to observe pile installation, your boss asks you to come up with a plot of Npile (X-axis) versus Qall (y-axis), so you know when you have developed adequate capacity for each pile that you are driving. When you asked your boss about the equipment that would be used for driving the piles, she said that she was pretty sure you would be using a drop hammer with a ram weight of 5,000 lbs and a drop height of 3.25 ft. a. Please develop this plot using the simple ENR formula that we discussed in class, and make a recommendation about a minimum Npile value that you would use to determine pile acceptance, given that Qapp = 30 kips for each pile once the structure has been fully constructed. b. Given that the concrete piles are all one-foot square, with 4 1" diameter round steel reinforcing strands running along their lengths, is there an Npile value that you would not want to exceed because of structural capacity limitations of the piles? To perform this analysis, assume that the ENR formula accurately estimates the stresses applied to the pile during driving (in the real world, you would want to do this with the wave equation). Given: allowable stress of steel = 20 ksi. Allowable stress of concrete = 3 ksi. Assume that, during driving, you want to keep the applied driving stresses less than the allowable stress for the pile cross section.