Questions tagged [structures]

Questions relating to or the engineering application of a device that must withstand a loading via deflection, stresses, resistance to buckling, or natural frequencies.

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2
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1answer
122 views

Siding for Industrial Shed: Rain protection vs Ventilation

When building a 12 m tall industrial shed with a peaked roof it is desirable that the sides of the shed should stay open as much as possible for ventilation / safety / access concerns. On the other ...
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1answer
161 views

Mechanism to continously lift grains and put them on a conveyor belt [closed]

I am an electrical engineer, making a hobby project on an automated unwanted-material-removal system in grains and pulses (rice, wheat, etc). I am well versed with programming and electrical stuff, ...
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2answers
1k views

How is biaxial bending considered for reinforced masonry design?

I am faced with a problem where I have to design a reinforced masonry beam for biaxial bending. The governing code is ACI 530-11. I cannot find a provision in this Code for biaxial bending. The only ...
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3answers
546 views

How different is using styrofoam rather than empty cans when pouring concrete?

In the recent 6.4 earthquake that hit Taiwan, it was seen in a newswire photograph of rubble that metal cans were embedded in the concrete. The quote from an official regarding this practice: For ...
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3answers
3k views

Does the length of a beam change upon deflection?

I have made a Python program in which I have computed the deflection of a beam. I am plotting the deflected beam and am now asked to show the length of the beam. If the beam is not deflected, it is ...
7
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1answer
2k views

How do you check a weld for applied moment?

I have a single angle connected to a double angle via a 3/16" weld I know there is a factored, applied moment at that connection. I would like to ask how I can go about checking the capacity of this ...
1
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1answer
306 views

How to transfer reaction forces of beam to a weld?

I have modeled a beam as fixed-fixed. The reaction forces are -1494 lb.ft and 761 lb (vertical). There is no horizontal reaction. Now I know this beam is welded to another element. I am trying to ...
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2answers
1k views

How to calculate a structure's ultimate load [closed]

Sorry in advance if this question is excessively noobish or seems lazy. I have no engineering background and am unsure where to get started tackling this problem. Links to resources that could put me ...
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3answers
5k views

What are safe locations for openings in reinforced concrete beams?

I had an argument with a friend about the safe location for openings in reinforced concrete beams. I've chosen position 1, a little above reinforcement steel, as at this location, the beam is ...
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2answers
166 views

How Do You Determine Truss Stability in a Modeling Program?

This question originates from this and that question. I have realized the concerns boil down to the following figure. Simply put, is the truss above, with the displayed boundary/internal fixity ...
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2answers
447 views

Removing beam deflection through axial force

It's been a while since I've done any comprehensive work with structural dynamics, so let me know if I get anything wrong here. I have a horizontal beam that is clamped on one end and free on the ...
4
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1answer
230 views

What is the correct term for long cuts in a floor joist?

I would like to identify the correct term for a long, lateral cut within a floor joist. Based upon this guide and several other sources that I have come across, a ...
3
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1answer
352 views

How do I create a graph of the phase angle and response of a harmonic excitation in Matlab?

In my course of dynamics of structures, I am struggling with some basic principles. As a practice, I am plotting (or attempting to plot) the curves that are shown in the course book, with the help of ...
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1answer
617 views

Which is the best way to construct a trapeziun dome with a 76' diameter

When building a trapezium dome, is it better to construct the dome row by row or by first making a vertical arch? Is some form of bracing required?
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0answers
858 views

best way to reinforce existing structural header?

House remodeling. I need to enlarge (from 7 to 10-12 ft) and shift (about 5ft sideways) an existing header where one passes between rooms. On one side, the header has 2x8 ceiling joists nailed to ...
3
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1answer
1k views

How to estimate the required thickness of a transfer floor

I am examining a high rise building project of 30 floors with a podium underneath and 2 basements. The structure in the tower and the podium varies between flat slabs, steel structure for wide spans, ...
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2answers
4k views

Best angle and length for a diagonal wood support for a pull-up bar

I want to construct a freestanding pull-up bar like the one described here. But I was wondering what would be the best angle for a diagonal support considering that the things I care are: That it ...
3
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1answer
281 views

Calculating stresses of section with varying depth

I'm trying to solve the question attached below (please note the handwritten values are ones that I calculated/not part of question) I am assuming that to find the load $q$ I need to get the bending ...
2
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1answer
4k views

Finding Neutral Axis of a simple shape undergoing axial load

I know that the neutral axis occurs where the sum of stresses (bending + axial) is equal to 0. I have found the stresses and drawn a diagram to represent forces. How do I determine the neutral axis?
11
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3answers
2k views

What kind of protection should I give structural steel in a natatorium (swiming pool) environment?

What would be the best type of steel to specify? Would a heavy galvanization suffice? Are there specialty paints/coatings available for this particular application? If so, how long do they last?
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1answer
1k views

Loaded Truss problem

Hi, I'm having some problems with this truss question that I have in my homework. So far this is my solutions. I worked out my solutions to the reaction forces but don't know if they're correct. The ...
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5answers
9k views

Is hydrostatic pressure a dead load or a live load?

I have a structural analysis question. I want to know if the hydrostatic pressure in a water tank is a live load or a dead load and why?
6
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1answer
484 views

Dynamics of structures: combined plane stress and plane strain conditions

Problem statement For an engineering project in school, we are checking the stability in the longitudinal direction of an apartment building, taking into account the dynamic effect of earthquakes. ...
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2answers
426 views

First glance: structural integrity of this roof

There's a rooftop we recently discovered with a great view, and it's easily accessible for us. Obviously we'd like to go up there a bit more, particularly in summer with a couple of fold up chairs or ...
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1answer
1k views

Calculating automotive suspension wishbone loads by considering the structure as a 3D Truss

I am trying to calculate the loads in the suspension components of a typical car double wishbone setup. I have found a thread on the www.fsae.com forum, which seems to be exactly the kind of thing I ...
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3answers
407 views

How much strength does adding a T piece add?

If I have a flat span of steel material, 3.0m x 150mm wide and 5mm thick, and apply an increasing downward force to the middle, at some point it will fail. But if the profile of that piece of steel ...
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1answer
712 views

FEM 3D truss analyzer produces forces that do not sum to zero at joints

I am writing some code for the analysis of 3D truss structures. The program is a typical implementation of the direct stiffness method for truss elements. While testing it and comparing results to ...
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3answers
1k views

Is a permanent platform that is hanging and moving a dead load or a live load?

If a permanent room or platform is suspended from a larger structure (say, on a cable that is attached to a hook on a track in a ceiling) and designed to be in constant but not necessarily repetitive ...
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3answers
496 views

Is a distributed load in two parts equal to a full distributed load?

I have a structure like such: Due to my lack of knowledge of ANSYS, I have made the singular distributed loading (GI) represented as two distributed loadings (GH and HI). Would this be an accurate ...
13
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1answer
985 views

Why does prestressing in trees make them stronger?

In "Structures: or Why Things Don't Fall Down" James Gordon talks about trees being prestressed with the outside in tension and the inside in compression. Why does it make a tree stronger to have it ...
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0answers
292 views

How to account for pistons inside a free body diagram? [closed]

If you have taken basic statics classes you'll remember the free body diagrams used to calculate the forces inside a mechanical system; such as a beam structure consisting of pivots, rollers, fulcrums ...
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2answers
1k views

Why are three way bridges rare?

It's true that most bridges are "two directional." But three way bridges are pretty rare, globally. I can understand why there wouldn't be many for rivers, but if bridges are designed based on the ...
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1answer
1k views

How high can you stack mobile homes?

In Ernest Cline's novel Ready Player One, the main character lives in the "stacks" - a dystopian vision of what a trailer park may look like in the future. The "stacks" are primarily composed of ...
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1answer
277 views

Is a building story actually 10ft (3m)?

In common US usage, the heights of tall things are sometimes converted to a "number of stories". The thinking is that people can better compare heights to similar tall buildings that they might have ...
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1answer
450 views

Is there a theoretical bound to how tall a structure can be built?

Assuming that there are no constraints on cost, land to develop, or supply of materials, is there a theoretical limit on how tall a structure can be built? What are the main physical constraints that ...
7
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3answers
692 views

What concerns would I need to consider for building a swimming pool of gold coins?

If I wanted to build a gold coins swimming pool [as in DuckTales], what engineering (not security) concerns would I need to address to make such a pool feasible? For example, since gold is much ...
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2answers
1k views

What is the best insulation wall for a house? ACC wall, Cavity wall, etc

Normally, people use Autoclaved Aerated Concrete (AAC) to build a concrete house because ACC is a good thermal insulation brick that easy to buy and not expensive ...
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1answer
2k views

Why build a cell lattice tower with square cross-section instead of triangular cross-section?

First, a neat image from Wikipedia Here the cell tower has three vertical (or maybe slightly inclined to the inside) thicker pipes which are located at angles of a triangle and those three thicker ...
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1answer
1k views

Why are hyperboloid towers not popular anymore?

Hyperboloid towers were very popular in the end of 19th and the first half of 20th centuries - water towers, powerline anchor towers, sometimes tall radio towers were built using this design. The ...
13
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1answer
365 views

Additional jacking force to overcome stiction/dry friction

It is common to lift bridges to replace bearings, etc. In an ideal world the lifting capacity required of the jacks would be the self-weight of the bridge divided by the number of jacks (+ allowances ...

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