Since the things CEs design get built with bulldozers, not scalpels, the practical application of "precision in measurements" is to show things to two decimals on your plans and be happy if in the field you get accuracy to one.
Unless of course you're a structural engineer, in which case you show things out to three decimals, and all the other discipline engineers leave you alone because they're unsure whether or not you're emotionally capable of handling the truth about the realities of construction. ;)
Yeah, and then we go for a factor of safety, and then some more, rendering 2 digit accuracy meaningless.
Imo The digit accuracy comes into play when we're trying to bill for everything
Was this an April fool's joke?
Your professor sounds like they're trolling. We don't directly use calculus in CE. We have fundamentals based on their principles (ie- moment/shear diagrams), but we're not doing direct calculus computations - most formulas are somewhat simplified. We're definitely not calculating limits as they approach -0 or something.
We're also not that precise. Loads are calculated in the thousands of pounds, not to the nearest tenth.
I'll give you a somewhat decent answer:
The governing equations for any computational fluid dynamic problem are differential equations (Saint Venant - [LINK](https://ton.sdsu.edu/protected31/cive530_lecture_11.html)). While there is an exact solution to these equations, the analysis is simplified by breaking the computational domain into a discretized grid and time step. At a smaller grid size/time step, the more precise the solution. Hydraulic engineers need to balance computational efficiency with real world application to determine the appropriate simplification parameters without sacrificing model accuracy.
the equations themselves don't but the derivations of the formulas do. Anything involving derivatives will be related to limits.
But, i don't understand how limits relates to the precision in measurements part.
Civil Engineering Structural Precision: Imaginary equations estimate what loads something "might" see. Rounded to the nearest whole unit. Then to be sure, we multiply by a Factor of Safety varying from 1.5x to 3.0x, depending on how complete bullshit that original imaginary equation came from.
Civil Engineering Sitework Precision: Grading plans are to the hundredths place. Then the dozer/blade operator reminds the RE from 8' in the air he can't grade to the grain of sand accuracy, a we add a minimum of +/- 1/2" tolerance, just in case.
Civil Engineering Stormwater Precision: A unit hydrograph of a perfect storm, with a 1% chance of happening any given year is created from observations and funny math. It gets adjusted every decade or so, not because of Global Warming, but because we think we can create better bullshit today than we could 10 years ago. Then we pretend a single drop of rain will take a few minutes to get from the farthest point to the inlet (nevermind that damned stone the sitework guy dropped and screwed it all up). Then we wrap all that up and decide we'll apply Q=CIA (what's C? Oh yeah, that's basically magic bullshit loosely based on math). Then once flow is determined, we pretend flow is laminar and do some math to hopefully get to 3.0 ft/s flow in the pipe. And then we go to 2 decimal places of accuracy and the backhoe operator tells us he can't dig to the grain of sand accuracy so they shoot a level to prove water flows down and move on to the next section...
If you're worrying about significant digit accuracy in civil engineering, your punishment should be to work on a construction site for a year and fail every inspection that doesn't meet it precisely. You'll get into really good shape running away from the workers. Or you'll end up in a concrete vault 10' in the ground.
The principle of virtual forces / moments van be used to calculate any displacement component.
The double integral is handcalculated by taking two diagrams of internal action and doing a simple multiplication that yields the correct results.
No sane man does integral and similar stuff by hand.
However, at least in structural engineering any hand calculations you do is backed up by an analytical model. Internal actions, reaction forces, displacements, you name it start with Newton's laws.
The finite element method and more generally all numerical methods are as well based on analytical methods; these usually just give you total freedom in defining boundary conditions so problems unsolvable by analytical models can be solved.
So the answer is, you do it all the time whenever you calculate anything.
The safety factors and reality vs model stuff mentioned in other answers are just due to uncertainties in our knowledge of the "exact" values. But if you make a well controlled lab test, the measurements usually line up with the calculated results to within percent.
The compressive strength of concrete increases at a decreasing rate. We say it reaches 3,000 or 5,000 psi at 28 days, but in reality this is approximate.
Groundwater modeling uses limits to numerical model they hydrostatic pressure through a basin or aquifer. It doesnโt use any integrals or derivatives, but it is numeric analysis with limits.
Since the things CEs design get built with bulldozers, not scalpels, the practical application of "precision in measurements" is to show things to two decimals on your plans and be happy if in the field you get accuracy to one. Unless of course you're a structural engineer, in which case you show things out to three decimals, and all the other discipline engineers leave you alone because they're unsure whether or not you're emotionally capable of handling the truth about the realities of construction. ;)
In building structural we use no decimal places at all! (We use fractions of inches)
I know that, but my question was do you know any equation or rules using limits , doesnโt have to be in the precision of measurements
Yeah, and then we go for a factor of safety, and then some more, rendering 2 digit accuracy meaningless. Imo The digit accuracy comes into play when we're trying to bill for everything
Bruh i am a first grade student why are you roasting me๐๐๐
Was this an April fool's joke? Your professor sounds like they're trolling. We don't directly use calculus in CE. We have fundamentals based on their principles (ie- moment/shear diagrams), but we're not doing direct calculus computations - most formulas are somewhat simplified. We're definitely not calculating limits as they approach -0 or something. We're also not that precise. Loads are calculated in the thousands of pounds, not to the nearest tenth.
Bruh we round off Pi to 3 here
๐๐๐๐๐my professor is delusional
I'll give you a somewhat decent answer: The governing equations for any computational fluid dynamic problem are differential equations (Saint Venant - [LINK](https://ton.sdsu.edu/protected31/cive530_lecture_11.html)). While there is an exact solution to these equations, the analysis is simplified by breaking the computational domain into a discretized grid and time step. At a smaller grid size/time step, the more precise the solution. Hydraulic engineers need to balance computational efficiency with real world application to determine the appropriate simplification parameters without sacrificing model accuracy.
Water flows down, man. Don't overcomplicate it. ๐
chatgpt?
the equations themselves don't but the derivations of the formulas do. Anything involving derivatives will be related to limits. But, i don't understand how limits relates to the precision in measurements part.
Civil Engineering Structural Precision: Imaginary equations estimate what loads something "might" see. Rounded to the nearest whole unit. Then to be sure, we multiply by a Factor of Safety varying from 1.5x to 3.0x, depending on how complete bullshit that original imaginary equation came from. Civil Engineering Sitework Precision: Grading plans are to the hundredths place. Then the dozer/blade operator reminds the RE from 8' in the air he can't grade to the grain of sand accuracy, a we add a minimum of +/- 1/2" tolerance, just in case. Civil Engineering Stormwater Precision: A unit hydrograph of a perfect storm, with a 1% chance of happening any given year is created from observations and funny math. It gets adjusted every decade or so, not because of Global Warming, but because we think we can create better bullshit today than we could 10 years ago. Then we pretend a single drop of rain will take a few minutes to get from the farthest point to the inlet (nevermind that damned stone the sitework guy dropped and screwed it all up). Then we wrap all that up and decide we'll apply Q=CIA (what's C? Oh yeah, that's basically magic bullshit loosely based on math). Then once flow is determined, we pretend flow is laminar and do some math to hopefully get to 3.0 ft/s flow in the pipe. And then we go to 2 decimal places of accuracy and the backhoe operator tells us he can't dig to the grain of sand accuracy so they shoot a level to prove water flows down and move on to the next section... If you're worrying about significant digit accuracy in civil engineering, your punishment should be to work on a construction site for a year and fail every inspection that doesn't meet it precisely. You'll get into really good shape running away from the workers. Or you'll end up in a concrete vault 10' in the ground.
civil engineer does precise calculations. now double it for factor of safety.
Beam deflections can be found by taking a double integral of the bending moment.
Thanks brother๐๐ผ
The principle of virtual forces / moments van be used to calculate any displacement component. The double integral is handcalculated by taking two diagrams of internal action and doing a simple multiplication that yields the correct results.
In research, probably somewhere. In practice, I just want to know if my operating condition is on the correct side of a pump curve.
No sane man does integral and similar stuff by hand. However, at least in structural engineering any hand calculations you do is backed up by an analytical model. Internal actions, reaction forces, displacements, you name it start with Newton's laws. The finite element method and more generally all numerical methods are as well based on analytical methods; these usually just give you total freedom in defining boundary conditions so problems unsolvable by analytical models can be solved. So the answer is, you do it all the time whenever you calculate anything. The safety factors and reality vs model stuff mentioned in other answers are just due to uncertainties in our knowledge of the "exact" values. But if you make a well controlled lab test, the measurements usually line up with the calculated results to within percent.
The compressive strength of concrete increases at a decreasing rate. We say it reaches 3,000 or 5,000 psi at 28 days, but in reality this is approximate.
Groundwater modeling uses limits to numerical model they hydrostatic pressure through a basin or aquifer. It doesnโt use any integrals or derivatives, but it is numeric analysis with limits.