rb1957, zeke, I think we're in agreement for sure.
13y+14X+468=0 as you guys pointed out is:
y=1.08x + 36.92
I think the book should have given the answer as an equation like that.
hydtools, you are correct. In order to derive a specific answer to the problem, (hence the given answer) there will have to be an additional condition that allows the formulation of a 4th equation to solve for X & Y.
However, there is no such condition presented in the book thus the form -13i...
rb1957, I came to the same conclusion too. Unless there exist another set of requirements, the location of the force is almost infinite.
For this case, I would think that all external forces acting on a solid body should be confined to within the boundaries of the solid body such that the point...
rb1957, what you just calculated was what I obtained if Y=0, then X=468/14, or 33.43" to the right of point a.(from eq. 13Y + 14X-468=0) which is what you have.
However, this is not the answer provided which is why I'm scratching my head to begin with.
It states that the force on the solid...
rb1957, to be sure I understand this, are you saying that from the moment equation in which I got 13Y + 14X -468 = 0, X & Y can be arbitrary as long as it satisfies the solution?
So if X = 0, then Y = 36....etc?
The answer provided in the sample is X=30.9", and y=2.77" from the lower left...
Cockroach,
Summing forces in the horizontal and vertical direction does not give me an equation with the required distances X & Y.
I only have 3 (Sum Fx, Sum Fy, & Sum Moment at point A) equations with 4 unknowns.
Am I still missing something?
Thanks Again.
Hi All,
Just a trivial question. I'm trying to prepare for a PE exam and came across a sample question that seems to escape me. I just need a nudge in the correct direction.
I've enclosed the diagram to the problem. It is asking me to find the magnitude, direction, and distance from point A of...
Gwynn,
That makes sense as most of these platforms we deal with are strictly for maintenance personnel only.
IFTs - Thanks for your viewpoint. However, in our profession, it's not the point of trying to weasle out of things but taking the best approaches to solutions both from a safety and...
doct9960,
You're correct. My area is mechanical. However I find my scope spanning across structural issues quite a bit lately.
We normally have a structural engineer to sign off on such designs prior to erection but I normally have to do a preliminary design layout for R.O.M. purposes.
BTW...
JStephen
Yes. The reason I'm sure is because the installations are based on customer specifications that require either 100 psf or 125 psf ratings on platforms. Most of these setups are typically for elevated equipment structures or equipment mezzanines if you will. We have concentrated load...
hokie66, what if like you said, that it is unlikely that the live load is present over the entire area at any one time?
Does the BOCA National Building Code or IBC contain information showing when and how much to reduce live load reactions?
Thanks for the clarification about the deflection of...
I would like to pick the brains of you experts out there about the proper calculation method of a support structure for platform.
For discussion purposes, let's say that I have a platform 3' wide x 10' long (19W4, 1" x 1/8" grating) that is simply supported by tube steel at the ends. (Think...
Hi All,
I'm even embarassed to have to ask this. But can someone remind me of how I can calculate the reactions at the 4 corners of the rectangle if the CG of the part is offset as shown? The weight of the part is 10 lbs. If the CG is at the center, then we know the reactions should be 10/4 =...
