Questions tagged [structural-engineering]

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

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23 views

I work at a museum and we use weighted free standing walls to hang artwork in the center of rooms. Could someone recommend how much weight to use inside our walls to ensure stability with the ...
12 views

Glue type for HDPE

What type of glue should be used for HDPE sheet to glue to itself And what type of glue for HDPE be glued to wood?
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Find out the loads acting per unit length on the beams supporting an open well stair

Please see the attached picture. I want to find out the dead load per unit length and live load per unit length (both in kN/m), that will be acting on the floor beam (300 mm × 450 mm) and the landing ...
19 views

King post truss question

Problem: Sagging roof in the middle of a garage. I could sister the bottom cord and/or add struts from bottom cord to the rafters but room is very limited. Question: After jacking the trusses at the ...
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Framing material for a pickup bed topper for overlanding

and thanks in advance for your comments. I am looking for a light weight framing solution, for a diy truck bed topper to use while overlanding. The frame needs to hold about 300lbs dynamic load while ...
26 views

Are mutli-story structure slabs poured on-center?

What exactly does it mean to have a multi-storey building where each storey is 2.4 meters? I've read a lot of descriptions of buildings that say each storey is "2.4 meters" or "3 meters&...
26 views

Why do period and damping ratio affect acceleration?

In the table above, the period of the structure $(T)$, the acceleration coefficient on the structure ($g$ in terms of gravitational acceleration) $Sa(T)$, The damping ratio is expressed as $ζ$ . As ...
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How does one calculate the aerodynamic pressure on a spacecraft during Max Q?

Just as lift - off of a spacecraft commences, that spacecraft undergoes aerodynamic pressure. After a certain point, the spacecraft reaches Max Q or maximum aerodynamic pressure. I do know that Max Q ...
42 views

Steel beam splice design

What is a good source of design recomendations for beam splices? I'm designing a structure and I need some help with getting proper splice strength for certain beam size. To make it simpler, I need ...
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Names for 3d tensile structure

A naive natural language description might be 'pole supported by tent-like 3d wire net' for the depicted playground climbing arrangement made of rope with a pole in the center. Is there a more precise ...
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59 views

How to calculate the material and thickness I need for a certain force on it?

I am trying to figure out how to design how thick a material has to be so that the bar shown in picture 1 stays intact when a user is running on it. Background: The project is a treadmill and the user ...
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USD beam to support ultimate moment of 650kN-m, limited to an effective depth of 600mm and 300mm width. Effective depth for compression steel is 60mm

I don't understand how exactly can a beam as described can support a 650kN-m ultimate moment. The only allowed bars are 28mm∅ bars. Consider 40mm side covering and bar spacing to be greater or equal ...
40 views

Help with understanding needed rebar

I've received a structural engineer report where the engineer has defined the dimensions of the required padding. It's the padding that a steel column post will be bolted into. I noticed he's put some ...
62 views

Is there any standard procedure or guideline to solve complex asymmetrical trusses such as saw tooth type of truss used for polyhouse construction?

I want to solve for the dead load,live load as well as wind load for a saw tooth type of truss, which is asymmetrical in nature....generally used for the construction of greenhouse. I also want to ...
17 views

Mat Footing (Bending Moment Issue of the Short Strip)

Hi I'm a civil engineering student, I wanted to ask for help and clarification for the design of mat footing. I used the Rigid method and based my design on the ACI 336_2R and Foundation Engineering ...
43 views

How to build bench with a rocking top rectangular section?

I want to build a metal bench, maybe 2m x 50cm x 40cm(W). A bit like a weights bench. The flat top rectangular section you sit or lay on should rock maybe 30 degrees to each side. What parts would be ...
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How would you go about the steel columns being adjacent where an expansion joint is expected?

The building is a steel building with a composite slab. The expansion joint is required because the building is 60m in length. The problem is where the expansion joint is expected, the columns are ...
21 views

Can't find correct reaction loads for statically indeterminate problem

been working on this problem all day and I feel as if I am going crazy. I am using SkyCiv to confirm the right answer and cannot get close to it, I have messed up both my attempts at superimposing and ...
66 views

Static Equilibrium of Rigid Bodies

When we talk about the idea of static equilibrium in engineering mechanics we consider the idealized case of a body which is a rigid body, meaning it cannot deform. Then we solve for the 3 equilibrium ...
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How to calculate the height of the supporting structure of an arch and the thickness of an arch in relation to its span

Please refer to the attached image. We know that if an arch is X unit wide then the supporting walls should not be less than X/4 unit width for the structural stability. I would like to understand ...
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18 views

Find stresses involved and calculate magnitudes

I am new to mechanical design.What all forces and moments act on the hinge plate in following figure?How to find magnitude of stresses induced on the supports? Note: The spring is an expansion spring ...
39 views

Free body diagram problem: Linkage w/ magnets and friction hinge

I am a bit stumped on a IRL problem, which i simplified in the diagram below: There are left and right beams (gray) linked together by a friction hinge. The bottom beam (black) is connected to the ...
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Analyzing shear stress of plate

I would like to conduct a nonlinear analysis to obtain the stress-strain curve of a plate subjected to shear force, as depicted in the figure below. However, I am encountering difficulties in setting ...
31 views

Buckling length of continuous steel H columns in multi story buildings

I have seen that steel columns in multiple story buildings span multiple stories, in that case how do you calculate the buckling length for the column? do you take the whole column's height, or just ...
21 views

I have a question about INISTATE Code (Analyzing a curved plate)

I'm studying welding-induced residual stresses for curved steel plates. So, I need to use the INISTATE code taking initial stresses. This is the picture that I want to analyze. I divided a curved ...
1 vote
118 views

Determining the suitability of a timber joint in a given situation

There seems to be a lot of information around calculating the forces exerted on a structure. When joining wood, once the structural analysis is done, how is the performance limit of a certain type of ...
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1k views

How does a church built from stones survive 70 years under water?

Following the recent news about the Sau reservoir in Spain, the draught revealed an 11-century stone church which has been under water for 70 years since 1962 when the reservoir was built. How is it ...
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Combined shear stress due to shear force and torsion

Let's assume I have a rotating shaft supported with bearings at both ends. This shaft is exposed to a point load (by means of another bearing) at some point and a torque. I want to calculate shear ...
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DLC wear resistance

I read that a thickness of one micrometer of DLC coating (which, if I understood correctly, shows similar properties to diamond), increases the lifespan of an item plated with it from a week to more ...
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I'm Missing Something on Problem 3 in Section A5.4 of Bruhn's Analysis and Design of Airplane Structures

I've been working through the 1943 edition of Bruhn's Analysis and Design of Airplane Structures. I found an archive.org pdf version of the 1948 edition that includes answers to select problems, as ...
28 views

$𝛕_{xz}$ in the flanges of T and I Sections

When we have a T or I section under a shear force $V_y$ I usually must account for a horizontal shear force across the section's Z axis ($𝛕_{xz}$). I understand why a transverse shearing force would ...
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What does "dc" stand for in this Positive Bending Moment for Plastic resistance of a composite concrete slab formula?

I'm designing a building with a composite slab with profile sheeting and steel structure, while trying to test the resistance of the composite slab in "composite phase" to bending moment I ...
23 views

Is it OK to separate fire and structural analyses when analyzing a fire induced building collapse?

This is from NIST NCSTAR 1-6 It seems to me there are problems with this approach. The heat distribution depends on fire spread and ventilation paths, which in turn depend on the shape of tjr ...
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Conflicting steel strength Vs temperature graphs, NIST NCSTAR vs Engineering Toolbox

This graph is from NIST NCSTAR 1-6C And this graph is from the Engineering Toolbox. As you can see, neither the NIST yield or tensile curves match with the ET structural steel curve. Why? And which ...
28 views

Find the internal bending moment, Mc

A 7meter,m, long cantilever beam whose weight per meter is 19Newton, N, carries a load that varies uniformly from 43N/m, (Newton/meter), at the inbuilt side, point A, to 0 at the free end, point B. ...
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25 views

What is the shear force at point B? Is it +P or -P or zero? I am not able to find any source that gives the right information

I am not able to understand here that what should be the value of Shear force at point B. It seems to be a discontinous point, as there is point load there, but can we say about the exact value of ...
63 views

Counterweight requirement and platform design for motorised speaker stand stability

I recently bought my dream speakers (Dutch & Dutch 8c), but at the cost of having to preserve a minimalist interior for the sake of household peace. To that effect, I plan to construct motorised ...
23 views

Ando dots or holes in concrete walls

I am making a concrete poured wall with holes where the bars to support the wood frame remain. Question is with plywood supporting frame what is the greatest distance between bars that will still ...
9 views

Does the magnitude or range of interaction of a force affect which layer dominates the mechanical response of a multilayered structure?

Suppose I have a two-layered material, with a stiff and thin outer layer (high E) and a soft (low E) and thick inner layer. Intuitively, it feels like the effect of short-ranged forces (e.g., van der ...
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How is the number of memebers in a truss calculated?

In a fully connected truss (each node connected to all other nodes), the number of members (bars) is equal to $n(n−1)/2$ where $n$ is the number of nodes. I don't understand the derivation of this ...
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In this question, I solved the convolution for triangular pulse and the solution was Now take k = 1, m = 1 , And as R = Ku/P0, R = So, for t<td u(t) is a function of t and for t>td its a ...
62 views

Some questions about linear rail systems

there are many linear rail system configurations. Some with only one lead/ball screw in the middle and a moving platform with wheels aligning outside/inside/on top of one/two framing rail(s). Others ...
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Calculating the maximum force on a large cantilevered round steel bar that is used to support a tree house

Hi all and thanks for this page. I have constructed a large treehouse across two trees. The main support is provided by passing a very large 57mm dia high tensile steel bolt through each tree. Each ...
41 views

How do I find the pitch for the fly press?

To solve the problem first I need to find the pitch of the screw to find the shearing stress, is the stroke 45 degrees per 5.75mm or 90 degrees per 5.75 mm?
109 views

Is overpressure really an appropriate criteria for blast damage?

So, I went on Nukemap, and they gave me the following values for blast effects. 1 psi (7 kPa): windows break 5 psi (34 kPa): most residential buildings collapse These numbers are way too high. 1 psi ...
1 vote
37 views

How did gothic church architects/builders properly scale up their models to full size churches?

In this video the author explains how ancient church builders used models to determine the proper shape and order of installation of architectural elements in gothic churches. From the little I know, ...
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Are there structural (or code) reasons for choosing longer or shorter beam spans (besides bending moments, and ignoring cosmetics)?

When selecting the length of beams for a bridge, the better approach is to choose multiple full-length beams. Unless there is a compelling reason, one would not choose multiple shorter spans. An ...
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Can someone help explain the difference between strength and stiffness?

I just can't seem to get it through my head and I don't understand the difference. As far as I can understand, strength is a materials resistance to permanent fracture while stiffness would be ...