Wasabi
Moderator
  • Member for 6 years, 7 months
  • Last seen this week
  • Rio de Janeiro, Brazil
Foundation Excavation: How much larger than the RCC footing?
Accepted answer
3 votes

I don't know of any code which defines this, but a one meter "working perimeter" around the footing is probably more than enough. Regarding the slope of the excavation walls, that's trickier to ...

View answer
What are safe locations for openings in reinforced concrete beams?
3 votes

This is the sort of thing that is best defined by each country's structural codes. I'm from Brazil, so I'm going to use the NBR 6118, our concrete code. That being said, the general gist behind all of ...

View answer
How Do You Determine Truss Stability in a Modeling Program?
Accepted answer
3 votes

As mentioned in the comments to the question, since you are using a 3D analysis tool, you need to fix rotations around the X and Y axes. If you had been using a 2D analysis tool, simple pinned and ...

View answer
shear force calculation with velocity and mass
Accepted answer
3 votes

It seems like what you're really after is the force, not the mass. Now, if you're assuming that the plate will shear off, then the easiest way of calculating the force isn't through Newton's laws, but ...

View answer
Strand layout in prestressed concrete girders: is a partially filled bottom row acceptable/advisable?
3 votes

@hazzey has answered your main question quite effectively, so I'll just add two comments. While I agree that partially filling rows is perfectly fine, I would just like to add that it may be better ...

View answer
How monolitic is concrete when falsework is being crafted for parts of future structure only?
3 votes

In a continuous structure such as a beam or a column (under the expected loads for such elements), the structure is effectively indistinguishable from a truly monolithic one. This has to do with how ...

View answer
How to calculate the maximum size of a torus constructed in a given material
3 votes

I think there is no such limit. The only possible factor which comes to mind is the stress at the foot of the torus. If you momentarily consider the structure to be infinitely rigid, then the region ...

View answer
Is hydrostatic pressure a dead load or a live load?
3 votes

@grfrazee says it's a dead load, @NamSandStorm and @hazzey say it's a live load, and now I'm going to stop half way between them. It depends on what your tank is doing: Is it a frequently flushed ...

View answer
How is shelf deflection determined?
Accepted answer
3 votes

The exact deflection result is a function of the shelving's structural system. In the OP comments you mention that the two options would be either a wooden skin with metal edging or a wooden lattice ...

View answer
What is the effect of end diaphragms on prestressed girder forces/deflections?
Accepted answer
3 votes

I have no resources to point to in regards to this, but I'm fairly certain your gut-feeling is correct. In fact, end diaphragms exist in bridges primarily to hold the soil on the approach. They can ...

View answer
How do I calculate the forces on a desk and its legs?
3 votes

Since you want to know what happens with a load applied to the corner of the desk, I'm going to simplify this question into two dimensions, assuming that the leg on that corner resists the load alone. ...

View answer
Assuming identical hole perimeter, for which shape is the stress minimized?
2 votes

It depends on the loading conditions. It's important to note that the stress concentrations can be intuitively understood as created by the load's need to deviate from the hole. The larger the width ...

View answer
What are the units used in beam bending equations? Do they matter?
2 votes

What's an equation? In life there are two types of equations: theoretical equations are obtained from first principles: make some assumptions and then play around with variables until you get a ...

View answer
Is an axial force applied at the centre of a beam considered a compressive force, tensile force, or both?
Accepted answer
2 votes

I think your big misunderstanding is in this paragraph: [...] if I were to scan, starting from the leftmost side towards the right. I would initially see a compressive force onto the beam from R, ...

View answer
is this a picture of a plate girder train bridge or a deck truss train bridge?
Accepted answer
2 votes

It's a truss bridge. A quick Google Image search will make the difference between the bridge types clear. This is a plate girder bridge: And this is a truss bridge: Basically, a girder bridge uses a ...

View answer
What is "hyperstatic moment"?
Accepted answer
2 votes

To understand the hyperstatic moment, we need to first remember that prestress is, by definition, the application of an internal stress state on the beam. Therefore, it cannot generate external loads ...

View answer
How can deflection and spring constant of cantilever beam stack be calculated?
Accepted answer
2 votes

This is a case of a variable-cross-section beam. What you need to do in these cases is separate the cantilever into two parts: near the support it has one cross-section, near the free end, another. ...

View answer
Can changing the colour of roofs change the average temperature in a suburb?
2 votes

Yes, but probably no If we're feeling a bit pedantic, the answer is obviously yes: a suburb of white roofs will have a higher albedo than one with black roofs. It'll therefore reflect more light ...

View answer
Shear force and bending moment
Accepted answer
2 votes

So, in such problems, the first thing to do is calculate the support reactions. Thankfully you've already done that correctly, so we can move on from there. Now, something to keep in mind when trying ...

View answer
Statically determinate structure by adding moment
2 votes

If you think about it, a support is just an applied force or moment, right? If you have a simply supported beam with a force $F$ in the midspan, the supports will be two forces, each $F/2$ in the ...

View answer
How to determine impact load factor on small beams
2 votes

That equation does not distinguish between large and small beams. It is as valid in this case as any other. But this will only be a problem if $h \gg 0$. Remember that $h$ isn't the height of the ...

View answer
Why is local yielding considered the limiting case in context of buckling in Eurocode?
2 votes

Euler buckling is a perfectly elastic behavior: if a beam buckles, it takes a sinusoidal shape of arbitrary (possibly infinite) amplitude. If you then remove the applied force, the beam will return to ...

View answer
Which method is better to solve indeterminate trusses, force or displacement method?
2 votes

Depends on your definition of "better" and on the specific truss being analyzed. The displacement method is useful in that it is agnostic to such things, statically determinate and indeterminate ...

View answer
torque required to lift an object
2 votes

Since we're not having to deal with friction, conservation of energy is our best friend. There's no need to "convert rotational work into translational work", merely observe that they must be equal in ...

View answer
Problem while solving for the moment of a cantilever beam
Accepted answer
2 votes

This is cheating a bit, but let's start backwards by looking at the correct diagrams you've already shown us and comparing them to your solution. This will hopefully let you notice something which ...

View answer
Beam with constant load distribution on three supports - force distribution to supports
2 votes

This problem can be simplified by observing the symmetry. This allows us to solve only one side, considering it as a beam of span $L$ which is fixed and pinned: Now, reactions are really just ...

View answer
How to rate a davit beam?
2 votes

If I understood your description correctly, the structure is something like this (ignore the dimensions and loads themselves, they're simply representative of the relative values. Also, I didn't apply ...

View answer
Optimizing support board placement on work table wing
2 votes

As @hazzey mentioned in a comment under the OP, if nothing is going to break, then the choice is mostly arbitrary. So I'm going to assume that things do break. A structural element can basically ...

View answer
Deflection of parallel rods with force at an angle
2 votes

EDIT: Looking back at this answer I realize that the entire method is flawed. The final answers for $M_B$ and $B_y$, however, are correct. However, I believe this cannot be proven without FEA software ...

View answer
By what factor should I scale some tapered legs to make my harpsichord stable?
2 votes

If the legs are simply screwed at the joint, then they should be considered pinned to the base of the instrument. This means that the angle between a leg and the base (initially equal to 90°, with the ...

View answer
1
3 4
5
6 7
11