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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171 views

Heuristics for Efficient Structure (Shed) Design

Are there any heuristics / thumb-rules to evaluate whether a shed-structure has been efficiently designed? To be specific, I have an industrial shed, 12 m tall, 270 m2 floor area (longest span 10 m) ...
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3answers
433 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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2answers
43 views

What is the 'application standard' referred to in EN 1993-1-7

I'm using the Eurocodes for some structural analysis and am looking for the limiting value of deflection of a plate. EN 1993-1-7, Section 8.2 states: For limiting values of out of plane deflection w ...
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2answers
3k views

Two storey brick building without using wood or steel

Is it possible to build a two storey building just using bricks (no wooden beams, steel beams or steel reinforcement) to suspend the floor of the second storey? I'm aware that using wooden beams is ...
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1answer
1k views

Critical Buckling Load for a Spring Supported Bar

The above is a past exam question from an introductory structural analysis course, one in which although we have studied the Euler buckling load equation, we have just been given parameters for the ...
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1answer
334 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
174 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
89 views

Fixed-Free End Column Design

I am currently working on a problem where I have to design a column. The structure I am currently designing currently takes the following form, When designing the column, I know that I have to ...
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2answers
64 views

2nd Moment of Area of a ring

This is my first question here. I am having trouble finding the 2nd moment of area of a ring with a thickness 't' and radius 'r'. I seem to be a factor of 2 out. What I do is I consider an area like ...
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1answer
776 views

Can pinned support / pin joint transfer moments in 3D?

What's an authoritative definition of whether the idealized pinned support and pin joint can transfer moments in 3D? Most sources say both of them cannot transfer moments but are apparently only ...
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2answers
85 views

Stress yield of a specimen, result confusion

I am trying to calculate the static yield stress of a specimen using the 0.2% offset line on a stress strain curve. I found the static yield stress of the specimen to be the number in bold (104.1239). ...
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1answer
627 views

Determine the strain energy of a bar

I have a Structures question about determining strain energy that I am unable to solve. I have attempted it and I have the answer, I would appreciate if if someone can just tell me where I am going ...
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1answer
4k views

How to find the reaction forces, moments and the displacement of the fixed beam with a link?

The beam is fixed on both ends and there is a link in the middle. There is a force F on the link. My approach to solve this problem: A free body diagram is cut at the link and made into 2 systems. ...
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1answer
278 views

What is the logic to solve this cantilever problem?

I solved it using the logic that the vertical link of the beam is basically there to make the beam act like a cantilever. So I think it is a cantilever problem. Therefore, $$EI\frac{d^2y}{dx^2}=-px=M$...
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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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2answers
3k views

Beam with constant load distribution on three supports - force distribution to supports

I have following example (the question is at the bottom): The load distribution $q$ is constant. I add condition of zero bend in center of the beam, $w_B = 0$, and the assumption $F_{RA} = F_{RC}$. ...
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1answer
25 views

How to determine the fixed end moment?

I was trying to compute the fixed end moment for the beam (given below) using equilibrium equation for x, y displacement and moment but there are 4 unknown variables reaction and moment at both ends ...
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1answer
39 views

Reinforce foldable table legs

I'm trying to build a table with 4 swivel legs that can be locked into arbitrary angles so that it can stand over one to three rows of storage crates in my garage: As you can see, the legs aren't ...
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1answer
41 views

column yielding under earthquake

In the buildings designed with strong column weak beam concept, the columns will remain elastic, their plastic deformation will be limited. but this is not true at the base of the building. i mean i ...
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1answer
119 views

Is it safe to slightly cut the edge of RCC column for passage of pipe in bathroom?

The RCC column was cut in my absence due to passage of pipe for bathroom fittings. The thickness is about 1.5 in. Will it hamper the stability of structure?
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2answers
562 views

Buildings sinking into the ground

My friend has proposed that the buildings in the images below have been sinking into the ground over time and that they're not planned with basements. He thinks that the bottom of the building was ...
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1answer
62 views

Mounting outdoors camera using aluminum 5052

I designed a simple U shape 2mm sheet metal bent mount for a 4kg outdoors CCTV camera. The mount was accidentally produced from 5052-H32 Aluminum instead of 6061-T6. Is it common to use 5052 ...
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1answer
204 views

Stiffness as a function of thickness

Let’s say we have a thin band (made out of PLA, 3D printing material) with a rectangular cross section. In drawing, it would look something like this: Let’s say a force of 15 N is to be applied from ...
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1answer
108 views

strength of eggshell

It is a known fact that beams and spheres have the ability to carry relatively high loads. Beams are seen in bridges and other structures even since the days of ancient roman architecture. Spheres ...
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2answers
36 views

How much ballast is required in 110 mph winds to stabilize: a 60 lb., 20’ pole; 3' below ground/17’ above ground, with a 24lb. wind turbine atop it?

I can’t seem to find an answer that doesn’t involve more than a ton and a half of concrete. The manual for the wind turbine reports that the load on the turbine in a 110 mph wind is only 155 ...
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2answers
186 views

Conveyor Truss Analysis Problem with loading

I've been working on a schematic and its been going beyond my comprehension; so i thought i should consult better structural engineers here. (I'm a fresh Civil Engr Graduate though) i have this ...
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2answers
73 views

How to find strain in an inclined member of a struss

I'm working through an FEA problem and I'm stuck. Question: How can I determine the strain in member 3 from displacements known at node 3? It's at 45 degrees, I know I should be using some $cos\...
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1answer
526 views

Reaction forces in a structure

I have the following structure, in which I am failing to calculate the two reactions: Cz (apparently vertical) and Dz, in the roller support of the beam. The beam length is 7.5 m, the reactions Az, Cx,...
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2answers
716 views

Steel Continuous Beam Structural Diagram

Here's an image of my structural plan that my group and I are designing for a university assignment. It is a 7-story steel structure with bracing at the two ends and at the verticle core near the ...
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1answer
4k views

How to calculate effective section modulus of a slender section?

Hi how to calculate the effective section modulus of a class 4 section using Eurocode 1993? Can someone show me an example? I tried searching online but cannot find anything useful. My main problem is ...
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1answer
652 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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3answers
39 views

Hollow (rectangular) sections versus solid sections

I have an engineering competition coming up and one of the things I need to build is structure with both compression and tension members. The structure is scored based on the load held/weight ratio, ...
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0answers
23 views

Help sizing of lug attachment flange/plate?

Apologies for the crude drawing attached, but here goes. Given Fx, Fy, and Fz loads applied at the lug hole, I've distributed the loading into each of the 6 fasteners to size them. I've also sized the ...
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0answers
25 views

When settlement criteria of a foundation is satisfied, bearing criteria is also automatically satisfied?

We design the foundations to settlement criteria than bearing correct? Because settlement criteria is stricter? I mean, can there be an example where the settlement criteria is satisfied but bearing ...
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0answers
18 views

Secure loads to gearbox shafts

I have a sculpture that is designed to rotate over 3 axes at max. 30RPM and is mounted on an aluminium disc. My plan is to use 3 of these geared steppers and secure the sculpture to the Z-axis shaft, ...
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0answers
146 views

Calculating diameter of steel rod required to not bend over a given length

I want to use steel (or other material) rods to support weight over a 900mm cavity. The weight that needs to be supported is technically unknown, but I'd specify some rough guidelines as: 100KG (max) ...
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0answers
31 views

Research based bridge project? [closed]

I am a fourth year civil engineering student at IOE pulchowk, Nepal. In our syllabus one practical based curriculum called Project Engineering has been added. I, along with 5 friends, are interested ...
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0answers
34 views

What does 'Analysis Model Value' in NASTRAN optimization mean?

I am new to MSC NASTRAN and PATRAN. I am running a simulation on composite laminate optimization. While creating the design variables for the study, I noticed that there is a parameter called '...
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0answers
67 views

Calculating the Structural Forces Required to Support a Robot on an Overhanging Beam

this is my first time posting on here and I have a question regarding the structural properties a beam will need in order to fulfill some requirements we have for our robotics team. The scenario is as ...
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0answers
363 views

Beam element stiffness matrix for variable area cross section with mass and shear center not coinciding

I would like to find the full (12 by 12) Timoshenko beam element stiffness matrix for a variable cross section with mass center axis and elastic center does not coincide. I have the full stiffness ...
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0answers
69 views

How to design a shelving unit out of McMaster Carr Struts? [closed]

I apologize for the complete beginner question. I'm an Undergraduate Research Assistant trying to design a shelving 8'tall by 10' Long, 4' wide shelving unit to support about 200 lbs. I'm designing ...
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0answers
31 views

How to support height extender on a rail?

I've got an 1/8" thick steel rail with 1.5" diameter and 15' in length sitting on two 5/32" thick steel rails with 2.5" diameter and 100" in length 14' apart: I want to add a diagonal support for a ...
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47 views
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0answers
39 views

Check of a nominaly pinned steel joint

I am interested how to check a nominally pined joint. Especially how to check its rotational capacity and whether i can define it as nominally pinned in structural fem model. I understand that there ...
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0answers
27 views

How to calculate a global strain from a field disitribution

For an arbitrary articulated structure subject to non-affine (non homogeneous) deformations, the components of the strain tensor are defined locally. Is there a way to calculate a numerical strain ...
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0answers
33 views

Pressure-volume relation of thin-walled shell [closed]

Attempt to edit into a more specific question as suggested by moderator: I would like define the shape and material properties of a 3D thin-walled shell/membrane-like structure (for instance a baloon)...
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0answers
73 views

How should I position two shelf supports for the minimum deflection? [duplicate]

The above is the shelf that I'm intending to put up. It will have two symmetrically placed supports. This is probably a simple question that really should be answered in all DIY shops but... ...
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1answer
7k views

How much weight can this stand hold?

I got this stand from a friend of mine years ago. Its unbranded. I want to use it to hold a 55 gallon fish tank which can weigh about 456 pounds to 622.5 pounds. How can i calculate a estimate of how ...
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1answer
402 views

Calculate mobile base weight to support adjustable arm

I want to calculate how heavy a mobile hydraulic post table base must be to support an adjustable monitor arm and monitor. Monitor (iMac) Specs: Height: 20.3 inches (51.6 cm) Width: 25.6 inches (65....
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0answers
560 views

Suitable tube materials for making a light-weight, heavy-load bearing structure [closed]

I am looking to build a detachable hammock stand structure for camping. I was originally thinking about making one out of PVC but I am in the UK and it isn’t cost effective as it looks like it needs ...