Questions tagged [structural-engineering]

Questions related to the integrity, design requirements, or analysis of structures.

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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 ...
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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 ...
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1answer
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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?
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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 ...
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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,
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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 ...
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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 ...
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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 ...
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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 (...
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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 (...
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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 ...
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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, ...
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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 ...
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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 ...
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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 ...
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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)...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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2answers
63 views
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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 = \...
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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 ...
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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 ...
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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 ...
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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?
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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,...
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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 ...
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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 ...
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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, ...
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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, ...
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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 ...
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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?
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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 ...
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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 ...
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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 ...

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