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sunnykc999

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I have a structural question I’m trying to understand and could use some help please. When trying to find a max moment for a beam the given eq is Pab/l. In the NCEES HB it states: P=kips, a, b, and l = inches. But in multiple practice problems that isn’t how you solve it. Solutions use lbs and feet. Many problems seem to mix this up and I understand units need to be the same when solving but following the HB doesn’t appear to provide correct solutions. Can anyone clarify? Thx for any advice structural is my weakest area for sure .
Convert inches to feet - problem solved.
 

tarvis14

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I have a structural question I’m trying to understand and could use some help please. When trying to find a max moment for a beam the given eq is Pab/l. In the NCEES HB it states: P=kips, a, b, and l = inches. But in multiple practice problems that isn’t how you solve it. Solutions use lbs and feet. Many problems seem to mix this up and I understand units need to be the same when solving but following the HB doesn’t appear to provide correct solutions. Can anyone clarify? Thx for any advice structural is my weakest area for sure .
Units carry through on these formulae for shear/moment. So Mmax=P*a*b/L = (10kip) * (5ft) * (20ft) / (25ft) = 40 kip*ft = 40000 lb*ft.
If you didn't know these units are consistent, you could convert to handbook units as noted by sunnykc999 above
 

Pra4surf1

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Units carry through on these formulae for shear/moment. So Mmax=P*a*b/L = (10kip) * (5ft) * (20ft) / (25ft) = 40 kip*ft = 40000 lb*ft.
If you didn't know these units are consistent, you could convert to handbook units as noted by sunnykc999 above
Thanks for clarification. Just seems like they’re asking you to convert feet to inches when plugging in numbers to the formula. Another example that’s not clear is vertical curves where sometimes L = feet and sometimes it = station feet but it doesn’t tell you which to use unless your already familiar with that type of equation.
 

Pra4surf1

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Units carry through on these formulae for shear/moment. So Mmax=P*a*b/L = (10kip) * (5ft) * (20ft) / (25ft) = 40 kip*ft = 40000 lb*ft.
If you didn't know these units are consistent, you could convert to handbook units as noted by sunnykc999 above
Sorry for the dumb question and after reading your response I asked myself what am I missing. I went back and looked at the problem again and missed the obvious answer choices were in ft-lbs. Clearly I was overthinking this one but talking it through with you guys really helped. Thanks!
 

tarvis14

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Sorry for the dumb question and after reading your response I asked myself what am I missing. I went back and looked at the problem again and missed the obvious answer choices were in ft-lbs. Clearly I was overthinking this one but talking it through with you guys really helped. Thanks!
Not too dumb of a question. Important to watch your units in answers because they will include an answer that isn't properly converted. This one had 40 lb*ft when it calculated as 40 kip*ft. This type of correct looking wrong answer is very common
 

sunnykc999

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Update: I passed the exam. Took it last Monday, results came out today! Let me know if anyone needs info on how I did it. Not anything different from what you are probably doing, but just in case.
What’s the study schedule and strategy and what depth portion you gave? Did you use EETUSA? How many hours you studied total and how many problems you practiced and which problems you practiced?
 

AngelaK

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What’s the study schedule and strategy and what depth portion you gave? Did you use EETUSA? How many hours you studied total and how many problems you practiced and which problems you practiced?
I just posted about this separately since I got a few messages on this. See here
 

sunnykc999

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I just posted about this separately since I got a few messages on this. See here
Thanks for the reply, I appreciate it.
 

Pra4surf1

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If someone could help me out on this practice problem I’d really appreciate it. For some time I was thinking the subtracted 35 from 60 was horizontal but now I’m thinking it’s vertical and while I can solve it just from repeating it still trips me up. Thanks for your thoughts!
 

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AngelaK

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If someone could help me out on this practice problem I’d really appreciate it. For some time I was thinking the subtracted 35 from 60 was horizontal but now I’m thinking it’s vertical and while I can solve it just from repeating it still trips me up. Thanks for your thoughts!

It is horizontal, from the edge of the building to the point where load is being placed. see if this helps.
 

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rodr

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If someone could help me out on this practice problem I’d really appreciate it. For some time I was thinking the subtracted 35 from 60 was horizontal but now I’m thinking it’s vertical and while I can solve it just from repeating it still trips me up. Thanks for your thoughts!
They skip too many steps for me.

I found the angle first and then used the angle to solve for my max x distance once the boom is touching A.

Hope this helps
 

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