# Questions tagged [columns]

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### 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): $$P_{cr} = \dfrac{\pi^2EI}{L^2}$$ ...
3answers
10k views

### 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 ...
2answers
3k views

### 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 ...
1answer
82 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 ...
1answer
400 views

### 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 ...
3answers
622 views

### 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 ...
1answer
1k views

### 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 ...
3answers
70 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 ...
1answer
7k views

### 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 ...
0answers
87 views

### 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 ...
1answer
65 views

### 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 ...
1answer
4k views

### How to find tributary area for a column when I have a transfer slab?

If I have a transfer slab in the basement level how to find the tributary area for the columns because the columns in the upper floors have different location and tributary area than that of the ...
0answers
298 views

### Shift Concrete Column by few inches

While building the foundation of a house, the concrete columns were built 15cm (6 inches) from the planned position, which is reducing the space for a door. The position that should have been there ...
2answers
493 views

### 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 ...
1answer
34 views

### Can the two columns and little triangle thing be removed?

Can the two columns and triangle thing be taken off so I can add a porch.Is it a major job?
1answer
45 views

### RHS column profile able to replace 3m UC 152x23 column?

I'm having some work done in the UK (Eurocode) which involves a steel column to support a beam at 1st floor (US: 2nd floor?) level. The column bears a very-close-to-vertical total load of 47.3kN (...
1answer
13 views

### 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.
1answer
45 views

### How to model leaning columns in opensees?

I want to modelling three buildings next to each other in opensees software . Duo to modelling leaning columns , buildings overlap with each other . Now my question is that for 3 adjacent buildings ...
1answer
45 views

### 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 ...
1answer
395 views

### How do i find the effective length factor (k) for a column from this chart?

I need to find the effective length of a column (kl) from this chart which can be found in the "design of concrete structure" By Dr. Arthur Nilson. the question states "if Psi top is 1.5 and the ...
1answer
34 views

### Flexure Deflection - Both ends fixed (one translation free)

I have a flexure problem. One of its ends is fixed to a frame (say F1) which is stationary (no rotation & no translation) and the other end is also fixed to another frame (say F2) which can move ...