Questions tagged [structural-engineering]
Questions related to the integrity, design requirements, or analysis of structures.
968
questions
1
vote
2answers
44 views
Shear coefficient for an I-Beam
I’m trying to analyze the bending of an I beam using the Timoshenko beam equation and I can’t seem to find the value for the shear coefficient anywhere.
Surely someone must’ve done the work (given how ...
0
votes
1answer
31 views
Question regarding the extreme wind velocity distribution in Eurocode
Above is the definition of the probability factor from Eurocode 1-4. It is used in context of calculating the extreme wind load on a building. Ignoring some other factors, it is used as follows:
$$v_b ...
0
votes
1answer
18 views
Should we split a building containing a factory and a storage according to (NFPA 13) code?
I asking for a building that contains a desalination plant and a storage of water bottles (in carton boxes).
Should we split the factory and the storage or not (according to NFPA 13)?
And which ...
0
votes
2answers
49 views
How is any kind of structural reliability achieved if the probability of annual wind speed exceedance is 0.02?
Above is the definition of fundamental basic wind velocity from Eurocode 1. According to its instructions, wind loads on building are supposed to be calculated based on this velocity. It says that ...
0
votes
0answers
14 views
Find orientation of reference nodes in Abaqus
I am constructing a simplified model of a pontoon-supported floating bridge in Abaqus. I have chosen to represent the pontoons as one-noded user-elements defined from the mass and stiffness matrix for ...
2
votes
2answers
43 views
Why is the yield strength of steel assumed to be less for a thicker element?
The above image is part of table 3.1 of Eurocode steel design standard. Looking for example at the first row (steel grade S 235), we see that there are two values for yield strength $f_y$, one for ...
0
votes
0answers
20 views
Boundary Conditions of a Stepped Beam
I would like to ask about the boundary conditions to be considered in a stepped beam. For a cantilever beam wherein the one end is fixed while the other end is free to oscillate along the z-axis, we ...
0
votes
3answers
58 views
Calculating Load On Winch From a Distributed Load?
I am in the process of building an antenna mast that can tilt from horizontal (down) to vertical (up). The mast (arm) is 360" and weighs a total of 105 lbs. I need to calculate the amount of ...
-4
votes
0answers
29 views
How to build instant mountain? [closed]
Create an instant mountain that is up to 2 km high, 5 km length, and 3 km width using expanding foam concrete.
Would it be possible?
Can we build houses on top?
-1
votes
1answer
45 views
Building lightweight 1 km high fence [closed]
I would like to build a fence that is 5 km2 and height of 1 km. This wouldn't be feasible as the material needed and cost implications plus environmental factors. Therefore I thought of finding the ...
0
votes
3answers
72 views
How to calculate beam impact problem
Can anyone help with this Impact problem? It does not seem very difficult but I am having trouble putting all the parts together.
Thanks,
3
votes
2answers
78 views
How to simplify a truss bridge diagram?
Hello I have this truss structure question. I understand that we need to determine the zero-force members first so that we can simplify the diagram. But I am not sure which one that I need to ...
3
votes
2answers
425 views
What does “crs” mean in structural engineering / construction?
In the realm of structural engineering, construction, foundation design, what is "crs" when talking about piles/posts? Is it an abbreviation? Does it refer to some sort of size?
Some ...
4
votes
1answer
106 views
Why is the Stress vs strain diagram preferable to the Load vs displacement diagram?
I’m really unsure what is the difference between stress vs. strain and load vs displacement graphs and why stress-strain is better.
I know that the units are different:
stress is in MPa and the load ...
2
votes
3answers
44 views
Confused about internal hinges for calcualting reactions
[]
I'm really confused about internal moments.
Regarding image 1,
When taking moments about D (the hinge), why does the book only consider the right side? Could you technically consider the left side (...
1
vote
3answers
66 views
How many support beams/rods needed for a firewood storage cabinet
I am building a firewood storage cabinet which should support around 100-150 kg of firewood.
The cabinet is made out of wooden boards (...
-1
votes
2answers
51 views
How can moving boxes not require any tape and still hold 50 kg of content without the bottom breaking when lifting them?
The other day, I bought a bunch of normal-price moving boxes. They come as one big cardboard unit which you bend in various ways. When assembled, they appear to be extremely strong and yet they are ...
1
vote
2answers
40 views
Civil Engineering - Detailing of free draining backfill and modelling of hydrostatic pressure in retaining walls
It is considered best practise to specify free draining backfill material (eg gravel) to be placed immediately behind a retaining wall. Supposedly, this alleviates hydrostatic pressure on the wall, ...
-1
votes
2answers
68 views
Pressure vessel wall dimensions
I am trying to design a small cooling setup which has two parts: the compressed air vessel and the turbines. My understanding is that the compressed air, upon being released, passes through the ...
0
votes
1answer
35 views
Economical difference with high-pressure vessel design pressures for fixed volume
Suppose space is not an issue and I need a fixed volume of compressed air (for storage), say 1m³. Is it more economical to manufacture a thick-walled vessel but with a smaller volume or a thin-walled ...
0
votes
1answer
60 views
Deflection Equation of a Stepped Beam
Help out a college student.
How do you derive the deflection equation y(x) of the shown stepped cantilever beam in the figure? Each segment has a unique Young's modulus and moment of inertia. The ...
0
votes
1answer
46 views
Is it possible to use Plain Cement Concrete post for fencing?
I am in need of around 700-800 posts to fence my farm in a semi-arid area in TN state, India. In my place granite posts mined from quarries are normally used. It costs around Rs 300-400 per post(6-7ft)...
0
votes
2answers
37 views
How much weight can a cardboard of size $n \times m$ hold? [closed]
I am interested in knowing how much weight a piece of cardboard can hold in proportion to it's size.
Suppose we have independent variables $x$ and $y$ corresponding to length and width and that these ...
1
vote
1answer
53 views
What is the characterising difference between a riser and a runner?
The image given below shows a bolster with a series of riser and runner. What I really do not understand is which is the riser and which is the runner. Also a detailed explanation to why multiple ...
0
votes
3answers
71 views
Why is it said that the flange of an I beam carries most of the moment?
It is often said for I beams that the flange carries most of the moment subjected to the beam, while the web carries most of the shear force. The latter is obvious from pictures like above, showing ...
0
votes
1answer
44 views
Cantilever beam
I want to design a cantilever addition. Over the driveway so I can't add supports.
I want to use the calculator here
https://calcresource.com/moment-of-inertia-rect.html
But I'm having trouble ...
0
votes
0answers
37 views
Large scale nonsymmetric standard and generalized eigenvalue problems in engineering
I apologize if this is not the right forum for my question, but I cannot think of better place to reach a large number of engineers within a short time span.
Question: I am a mathematician working in ...
1
vote
3answers
625 views
Why does the upper wing skin fail in buckling and lower wing skin does not?
I am aware of the fact that the buckling is mainly caused in the regions of the specimen which are in compression. But the wing skin doesn't take any axial loads and is used to resist shear, atleast ...
1
vote
0answers
34 views
Using seismic base isolators in light, flexible buildings
Using seismic base isolators dissipate a great deal of energy that would enter to a structure, but at the same time they increase the natural period of vibration of the structure. Now, if we had a ...
0
votes
2answers
63 views
Given the same diameter and height, which is stronger? A vertical standing cylinder or a vertical standing rectangular?
I am interested in two cases. Case 1: Both are solid. Case 2: Both are hollow with the same wall thickness.
0
votes
1answer
45 views
Boundary conditions for a cantilevered Timoshenko Beam
I am trying to find out the boundary conditions for above given Timoshenko beam. The boundary conditions that I have derived are
$x_1 = 0$
$$ \overline{u}_2^L = 0 $$
$$ \phi_3^L = 0 $$
$x_1 = \...
0
votes
3answers
67 views
How to derive fixed end moment of a beam fixed at both ends with a point force not in the center
So this is as far as I have gotten. The formulas written in green are the formulas that I have to find/ derive but I am hitting a wall. I know I am supposed to integrate but I am not sure where to go ...
0
votes
4answers
97 views
Deflection of a fixed-fixed pvc pipe under self weight
I would like to start by saying I am not an engineer, so I apologize if this question seems simpleminded.
I am making a manual tarp reel from pvc pipe, and I am trying to decided whether to use ...
1
vote
2answers
52 views
How to calculate the density of foam required to cushion impacts?
I have a treadmill desk and my downstairs neighbour is complaining about the noise. Specifically the noise made by the impacts of my walking. Unfortunately the floor of my flat is not concrete but ...
0
votes
1answer
29 views
Why Cold formed steel is becoming important for researchers? [closed]
A lot of academic research is happening on CFS and it has become very popular in constructions too. Why?
0
votes
1answer
38 views
Determine Stiffness (k) and Mass (m) of a system from impulse response
I have a test sample (Piezo Diaphragm) which I am actuating with a voltage supplied to the sample to assess the impulse response.
When this voltage is supplied to the sample a deformation per unit ...
11
votes
5answers
5k views
Why are some public benches made with arm rests that waste so much space?
While watching a YouTube video today, I noticed this public/park bench somewhere in the USA:
It looks strange to me the way the arm rests on each side are so far into the bench, wasting a rather ...
6
votes
2answers
841 views
How to indicate bolt direction on a drawing?
Consider the following steelwork drawing:
The location of the 6 no. M12 bolts are indicated with a circle and cross.
However, it is not clear whether the shank of the bolts should point into or out ...
0
votes
1answer
42 views
Why isn't there yet such a thing as a “Minimum Life Module” standard and concept deployed? [closed]
Why are large companies not producing, selling and maintaining the concept of "Minimum Life Modules"? What I mean is a standardized "module" hosting exactly one human being, with ...
0
votes
2answers
85 views
Pull force on bolt
I am considering a part of a steel column. A horizontal force of 5 kN is acting on the top part of the column. The distance from top to bottom is 500 mm. The distance between the two bolts in the ...
0
votes
1answer
54 views
compression buckling of frame
all. The top beam is subjected to uniformly distributed load. FYI, the column is 5m in length. As you can see, the major axis of column is connected to the beam with moment connection on top. However,...
0
votes
3answers
59 views
How to measure the stiffness of a rectangular beam, and compare it to a triangular beam?
I'm an amateur at engineering, working more on musical instruments, and I'm often in confusion regarding what exactly constitutes stiffness of a beam for a load applied on it so it could resist ...
1
vote
2answers
87 views
Can I convert multiple point loads into a single uniform distributed load?
I have a beam that has a given limit of 1690 lbs uniform load for a 24" span. I will be subjecting this beam to multiple point loads at different locations on the beam. In order to determine if ...
1
vote
3answers
71 views
Steel frame connection
this is a steel frame , top beams sitting on top of column with steel plate cantilever at both sides (one side longer than the other) , so there will be hogging moment at the center support. However, ...
1
vote
1answer
50 views
Same E for axial and rotational stiffness?
When we solve frames, we assume that the materials are infinitely rigid in axial direction, so all deformations are due to bending. So this means, we assume infinitely rigid modulus of elasticity, E, ...
0
votes
1answer
35 views
How do extra building levels affect the foundation design apart for the extra load?
I have been talking to some structural engineers trying to find one to design foundations for my contemplated bespoke building based on hi-cube 40-ft shipping containers. The initial concept is just ...
-1
votes
1answer
44 views
What affects LRFD strength reduction factors?
In LRFD strength reduction factors depend on the material and the applied load (shear, axial moment) too? Or just material? Are they also called resistance factor?
1
vote
0answers
18 views
In ASD do you divide elastic or ultimate strength?
In Allowable Stress Design (ASD) method, to find the allowable stress, do you divide the ultimate stress or the elastic stress (where the material becomes plastic) by the factor of safety? For example ...
0
votes
1answer
21 views
The difference between two load combinations in LRFD
In ASCE 7-16 there is a load combination as:
1.2D + 1.0E + L + 0.2S
but then there is also another combination as:
0.9D + 1.0E
In both of them earthquake load is the same so why would we use the ...
1
vote
0answers
36 views
Interaction of buckling modes
I'm reading this paper on structural members subject to both bending and compression.
In the first paragraph, in context of the equations 6.61 and 6.62, it is said:
The second two terms are modified ...
