Hondatek Posted February 3, 2015 Posted February 3, 2015 ok guys can some one explain the math so I can try to figure this out. page 19 in the Civil drafting book study unit. Thanks everyone Quote
Hondatek Posted February 3, 2015 Author Posted February 3, 2015 sorry uploaded it twice. here is the other question Quote
eldon Posted February 3, 2015 Posted February 3, 2015 The math is simple proportion. Understanding what information you are given is another problem. Quote
ReMark Posted February 3, 2015 Posted February 3, 2015 Well for starters "IE" (which should have been spelled out) stands for invert elevation. That's the elevation of the pipe entering/leaving the manhole. Sta. = station. Stationing usually starts at 0+00.00. Manhole #1 is at station 1+59.11 which is 159.11' (from station 0+00). Manhole #2 is at station 3+07.09 which is 307.09' (from station 0+00). For your first problem divide the difference in elevation of the two inverts by the distance between the two manholes then multiple that number by 100 to get the percent grade (slope). Can you do that? In the second problem you have been given the slope (or percent grade) and are asked to calculate the invert elevation of a pipe. Kind of the reverse of what you were asked to do in problem 1. Quote
eldon Posted February 3, 2015 Posted February 3, 2015 Do you have to use a calculator? It is easier to draw out, and you can see sense in the figures. Use the stationing along the x axis and the elevation along the y axis. Quote
Hondatek Posted February 3, 2015 Author Posted February 3, 2015 Ok ill work on it when i get back home from work. Thanks guys Quote
ReMark Posted February 3, 2015 Posted February 3, 2015 Re: second problem. Calculate the overall distance between the two manholes. Multiple that by the slope then subtract what you get from the invert elevation of 115.76 to arrive at the answer. Quote
Hondatek Posted February 3, 2015 Author Posted February 3, 2015 im going to do it from work boss not here today. ha ha ill post answer Quote
BIGAL Posted February 4, 2015 Posted February 4, 2015 Next step of the home work you now have the start and end info but need to draw the pipe but Horizontal & vert scales come into play or is that the next question ? Quote
Hondatek Posted February 4, 2015 Author Posted February 4, 2015 Remark and eldon, here is what I got 307.09 - 159.11= 147.98 248.33 - 234.58= 13.75 147.98 Divided by 13.75 = 10.7621818182 X 100 =1,076.21 not sure what the answer is here. Big Al this is the Examination part of the Civil Drafting. I started the drawing and thought it be better to read and take the test first. Quote
Hondatek Posted February 4, 2015 Author Posted February 4, 2015 i played with the numbers and its 13.75 divided by 147.98 = 9.29 so the answer to Q1 is C 9.29% Quote
eldon Posted February 4, 2015 Posted February 4, 2015 I sympathize with your "playing" with numbers, but you should know the reason for the answer. A slope grade percent is "Rise (vertical distance) divided by Run (Horizontal distance)" times 100 (for percentage) Quote
Hondatek Posted February 4, 2015 Author Posted February 4, 2015 That's why we are called students. see know I know how to do it. Thank you and remark for help. Quote
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