Engineering Stack Exchange
Engineering Stack Exchange

Questions tagged [columns]

25 questions
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2 answers

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): $$P_{cr} = \dfrac{\pi^2EI}{L^2}$$ However for $n > 1$, as shown below the buckling…
pauloz1890
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Would a PE-pipe filled with concrete make a good pillar?

An idea that keeps popping up in my head, that I don't know enough structural/civil engineering to know if it's good from a technical point of view. Take a piece of polyethelene (PE) piping, fill it with concrete, let the concrete bind. My…
mart
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6
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Tube Steel - ASTM A1085 vs. A500

Recently, tube steel manufacturers in the US have begun using the new ASTM A1085 specification for forming tube steel (a.k.a. hollow structural section or HSS) shapes, as opposed to the existing A500 specification. From what I've read (here and…
grfrazee
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5
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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 whatever structure the stairs are part of. The post…
Stilez
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Axial deformation of variable cross-section member

I've been given a problem which I've attempted to solve, and hope some fellow engineers could possibly see if my approach is correct. We are asked to calculate a column's axial deformation due to an applied load of F = 25 kN and the force due to the…
indigoblue
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Why would a column expand before accepting load through a narrow thunk?

Here's a column top which holds a driveway overbridge. The column is a reinforced concrete cylinder with an inverse truncated cone on top - so it expands sideways at its top. The column top holds some narrow thunk and that thunk holds the driveway…
sharptooth
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4
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Reinforced Concrete Columns - Interaction Diagram Question

I'm confused about some concepts concerning interaction diagrams for reinforced concrete columns. Hopefully somebody will be able to answer these: Point with zero tensile strain, but before uniform compression (no moment) In the calculation for…
Grady F. Mathews Iv
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Column Buckling Boundary Conditions -- Welded Tubing Practical Application?

I'm trying to do some calculations for a personal project. I'm trying to understand column strength / buckling. My questions relate to Effective Length Constant, which is based on Boundary Conditions (how the ends of the column are restrained) The…
zipzit
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For a column, what does "rotation fixed and translation fixed" mean

So there's a permutation of rotation and translation each being either fixed or free for a column. What do each mean? If the column is toe nailed to a plywood / beam underneath which is it? If it's in a steel bracket nailed to a column below what…
RLZaleski
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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 add some weight (and/or manufacturing complexity),…
ManRow
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Buckling of a cantilever with midway support

I'm trying to understand the implications for buckling and column sizing in the drawings below. A 3000mm 120x60 RHS steel column supports a 350mm horizontal steel beam. The column base and right side of the beam are both fixed but can pivot. They…
Stilez
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How to construct rcc column footing on rock?

I am constructing my house on a rocky plot. Some of the columns will be placed over rocks and we were not able to dig deep in the rock. So, these column footings will be on the surface. Is it safe?
Adarsh Ghagta
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Shear Wall Boundary Element

When can I design a boundary element of a shear wall as a column? Is there a link to a solved example? Help please.
ben asfan
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Simple steel column buckling calc - where am I going wrong? (Eurocode)

I'm trying to follow an example of this, but I get a wildly different answer than expected and I can't see where I'm going wrong. The example I've got, is for a 2.8 m steel column (RHS 150 x 100 x 5mm) fixed both ends with a simple static vertical…
Stilez
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Elution from an Ion Exchange Column

I am using concentrated NaCl(10%) to elute Cobalt (II) ions from a cationic exchange column. How would I determine the volumetric flowrate of regenerant needed to completely elute the cobalt ions from the resin?
E. Mackel
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