All Questions

Filter by
Sorted by
Tagged with
1
vote
1answer
36 views

What criteria must apply for torsional effects on this beam to be ignored in calcs?

I'm interested in how to work out whether torsional effects can be ignored or not, in calculating the adequacy of a given steel beam in the following idealised eccentric scenario. Or, equivalently, ...
0
votes
0answers
26 views

How to write the equilibrium stress equations for a hollow, rectangular beam?

I have a system consisting of a hollow, rectangular cantilever beam (pictured below). I'd like to write the equilibrium stress equations à la the Cauchy Stress notation. How do I account for the ...
2
votes
1answer
58 views

Why are variations zero on the endpoints of a beam?

On Wikipedia derivation on Timoshenko beam equation we arrive at this: $$ \delta U = \int_L \left[-M_{xx}\frac{\partial (\delta\varphi)}{\partial x} + Q_{x}\left(-\delta\varphi + \frac{\partial (\...
1
vote
1answer
84 views

Calculating area moment of inertia for a beam with underslung plate?

In a number of designs, a beam will have an underslung welded plate attached, as shown below: In this sketch, a symmetrical standard steel beam/column of dimensions H1 x B1, with web and flange ...
1
vote
0answers
47 views

Rotational bending in Timoshenko beam theory

The Wikipedia article on Timoshenko beam theory says: The model takes into account shear deformation and rotational bending effects, I am familiar with shear deformation, but what is meant by "...
0
votes
2answers
384 views

Shear force and bending moment for continuous span

It's given that L1 = 5m, L2 and L3= 7.5m, w = 8.9kN/m , I am asked to find the bending moment using these coefficient.. Prior to this , i need to have the value of shear force first.Shear force = ...
0
votes
0answers
37 views

Possible improved approaches to 6mx3m moment-resisting frame with eccentricity+torsion, in advance of detailed engineer discussion

I'm putting a steel frame in, to "open plan" the rear of a brick cavity-wall terrace house in the UK, which will then have a single storey extension added behind it. I have already retained a ...
0
votes
1answer
301 views

Shape Functions of beam element with 3 nodes (quadratic element)

For a two node beam element there are four shape functions for four degree of freedom: For a straight three node beam element how shape functions are? Please note that beam is straight and not ...
0
votes
1answer
32 views

Big Beam LVL or Glu Lam load capacity to support a gymnast

I need help knowing if I am selecting the correct wood beam. The load will be all near the center and a 250 pound man will be doing pull ups on it. I would estimate a 1,000 pound dynamic load to be ...
3
votes
1answer
154 views

How to measure the unbraced length of lateral torsional buckling for negative moment in a W-shape steel beam?

I have a W-shape steel beam that is fixed-fixed and the top flange is fully braced for lateral torsional buckling. The negative moment at the end controls the design and there is no lateral bracing ...
2
votes
1answer
67 views

Abaqus Failure for I-Beam Section in Major direction only

For my 4th year dissertation in Civil Engineering I've got to investigate the difference between BS5950, Eurocode 3 and ABAQUS failures. The only thing is, in the BS5950 and Eurocode 3 the failure can ...
1
vote
2answers
516 views

Deflection of a cantilever beam composed of separate (not bonded) planks

In the case of a simple cantilever beam having a uniform shape and being loaded at its end - the calculation of the deflection at any point along the beam is well known. What happens if we split it ...
1
vote
2answers
124 views

Is is possible to use singularity function to expresse the horizontal forces ?

I know how to translate torques and vertical forces into singularity functions, but may i also express the horizontal forces with singular function? if yes then what would be that expression? Here ...
1
vote
1answer
91 views

Shear forces along a beam using singularity functions

$\newcommand{\a}[1]{\langle#1\rangle}$ As you can see, the left end of the beam is fixed, and a distributed load is applied to the beam. I calculated the shear forces by conventional means, but when I ...
2
votes
1answer
349 views

Bending equation and max deflection of UDL and multiple point loads

I have a beam, simply supported with 2 points loads and 2 UDLs. The loads are symmetric about the centre of the beam. I've tried to derive an expression for the moment along the beam and then via 2 ...
2
votes
1answer
222 views

Timoshenko Beam Theory for Quasistatic Cantilever Beam: Shear Term

I'm trying to determine the effect of shearing force on the deflection of a quasistatic cantilever beam. In his book, Theory of Elasticity, Timoshenko added the following term to the deflection: $$\...
2
votes
2answers
54 views

How to find a beam for my (simple) application

I have a spanof 9m that I bridge with a (as yet unspecified) beam. From this beam hangs a load (a pipeline), right in the middle, of 4.295 kN. The beam is simply supported. I want to use an IPE steel ...
2
votes
2answers
1k views

Ceiling mounted punching bag without compromising structure or floor above

This question is regarding the safest way of installing a heavy punching bag of 100 lbs from the basement ceiling. Above the basement ceiling is a wood floor. The goal is to sleep soundly at night ...
1
vote
3answers
1k views

Transfering moment through internal hinge

My professor says, the internal hinge can not transfer moment: But can we calculate $\Sigma M_A=0$ for whole beam ( without cutting it or something) this way?: $\Sigma M_A=0 ===\Rightarrow M_A+(D_y ...
0
votes
1answer
57 views

Base Support for a Tree house

I am building a tree house in my backyard and it is going to be relatively simple. There are no parts that require drilling into the tree. The whole house is propped up by four 4x4 wood supports. I'm ...
4
votes
2answers
3k views

Multiple Varying cross section beam deflection

How do we calculate the deflection of a cantilever with two or three cross-sections, and different forces acting at the end of each section?
-1
votes
2answers
155 views

Engineering mechanics(statics) [closed]

I don’t get how to get the answer to part e. Should we assume reactions at A and B in all three figures are same? If so, why?
2
votes
3answers
57 views

Support columns inside metal tubing

Does structural metal tubing (e.g., either as HSS, or in space frames, or even motorcycle/bicycle frames) ever come with any small metal rods or columns inside of the tubing itself? While it might ...
4
votes
1answer
147 views

Why are steel I-beams mostly symmetrical?

From what I understand most types of steel are strong both in tension and compression, yet they are still usually significantly stronger in tension. Suppose a common I-beam supported on both ends and ...
4
votes
3answers
4k views

Are the points of inflection and contraflexure the same?

In theory of bending of beams, often these terms are used. There are no clear definition present. Most of them contradicting. Which of the property(bending moment and shear force) is zero in which ...
2
votes
4answers
128 views

Moment and Torque at a Single Point

As far as I know, moments/torques occur when forces applied are not in line. However, I often see moments/torques being applied at a single point in free body diagrams. How can moment/torque be ...
0
votes
2answers
6k views

how to solve internal hinge problem with loading given on hinge [closed]

how to solve internal hinge problem with loading given on hinge
3
votes
1answer
61 views

Is there a need to consider the moment generated by horizontal water pressure in a pool?

Suppose there's a pool which is supported by 4 beams (Perimeter beams)and 4 columns. When designing the beam should we consider the moment generated due to the horizontal water pressure? (I'm using ...
1
vote
1answer
93 views

Structural engineering: Would I need a beam for this? [closed]

If I was designing a simple gabled house with a 21 ft vaulted ceiling as the peak of the roof, and the house was about 32 ft x 40 ft with no load bearing walls (other than the 4 exterior walls)... ...
2
votes
1answer
2k views

Reinforcing beam and slab with correct steel bar structure

This question might look silly. I am not knowing the correct engineering terms to use in this question. I am trying to explain using the words what I know in English. We have been hired some ...
4
votes
2answers
2k views

Round beam deflection under its own weight

I'm trying to calculate how much simply-supported round beams of several materials and diameters deflect under their own weight plus an additional weight in the middle. I know the material densities ...
1
vote
1answer
2k 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. ...
1
vote
2answers
619 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 ...
-2
votes
1answer
2k views

How can we know “by inspection” the location of maximum deflection of a simply supported beam with a point load?

I am working the following problem: The simply supported beam shown in Fig. 12-12a is subjected to the concentrated force P. Determine the maximum deflection of the beam. EI is constant. ...
1
vote
1answer
994 views

How to calculate deflection of a cantilever beam subject to point loading

I am trying to solve the following beam deflection problem: The cantilever beam is subjected to the point load at C. Generate the equation for the elastic curve by using the double ...
4
votes
2answers
785 views

Given the tensile strength of a rod, how do you calculate the max weight that can be hung from it?

Given a 3.25" long, 0.125" diameter rubber rod with tensile strength 1200 psi supported on both ends, how much weight can you hung from the middle of it without breaking it? (This is not homework I am ...
0
votes
2answers
529 views

Maximum deflection of a beam, fixed in one end and concetrated load at free end [closed]

A 2 m long beam fixed in one side with a 2000 kg concentrated load at free end. Profile of the beam is HEB100 material S235. I would like to know if the beam will break under this load. If ...
1
vote
1answer
2k views

The boundary condition(s) for a continuous beam

I have a continuous beam across a center column (not sure whether I've draw it correctly or not) The Displacement and force diagram is as shown: The first diagram is the bending moment, second the ...
2
votes
2answers
400 views

Deflection of beam, according to thickness of top plate and bottom plate

When there is one rectangular beam like below image, I would like to know how the beam is deflected according to thicknesses of top plate and bottom plate. My concerning cross section patterns are ...
4
votes
3answers
4k views

Why does a continuous beam have less deflection than a pair of simply supported beams?

Inspired by this question, and also this answer to a separate question. I have two beam models, one with two independent spans (a full hinge), another is a continuous beam over both spans (only ...
5
votes
1answer
74 views

Can the thickness of a guard post be derived purely from energy principles?

Consider an ordinary staircase with a banister rail supported by a wall at one end and a steel post of constant profile at the other end. The base of the post is embedded rigidly in the fabric of ...
7
votes
1answer
598 views

Tolerance for Beam With Cope End

I need to have some beams fabricated with copes on the ends. They will be set on top of existing steel trusses, and used to replace undersized purlins to shore up existing rafters (hence the need ...
7
votes
2answers
271 views

What does it mean when actual member reaction is 100% of allowed?

I received construction documents for an extensive residential remodel and looking at the engineering there's a glulam drop beam with a calculated member reaction that is 100% of allowed (3965 lbs @ 5 ...
5
votes
1answer
2k views

Strength of a Vertical Round Aluminum Tube with load cantilevered off it?

Can a vertical round tube safely support a cantilevered arm mounted near the top of the tube? ROUND VERTICAL TUBE: 6061 Aluminum 2 inch Outside diameter 0.25 inch wall thickness 3 feet height ...
7
votes
1answer
303 views

Energy of a 3D Timoshenko beam

I am interested in the kinetic energy T and the potential energy U of a three dimensional Timoshenko beam. For a 2D Timoshenko beam the energies read: $$ T = \dfrac{1}{2} \int\limits_o^l \left( \rho ...
5
votes
1answer
2k views

What is the mathematical derivation for shear center of a beam?

For me, it's a bit hard to imagine where shear center can be, and what purpose it serves. The definition I found online is very vague: Shear center is defined as the point on the beam section where ...
1
vote
1answer
2k views

Beam Reaction Problem With Hinged Joints

The problem was assigned in my Structural Analysis class, and I am having some difficulty with it. My professor said the problem is "very easy" if we just think about what the fixed end moment on a ...
0
votes
1answer
6k views

Can I remove one or both of these support posts in my basement? [closed]

Below is a picture of two supporting posts in my basement. The posts are directly underneath the kitchen/dining room. Would it be feasible to remove one or both of the posts? What would the cost ...
5
votes
1answer
146 views

Why is this box girder made of lattice on one side only?

Here's a zoomed piece of this image from Wikipedia That's a close-up of a tower holding a railroad bridge. A and B are two of the four columns in the tower's corners. I assume that they are placed ...
11
votes
2answers
3k views

Buckling: Do buckling mode shapes of n > 1 occur in reality?

In the buckling of columns we know that: $$P = \dfrac{n^2\pi^2EI}{L^2}$$ The smallest value of P occurs when $n=1$ which gives a simple buckling shape (one wave): $$P_{cr} = \dfrac{\pi^2EI}{L^2}$$ ...