Design Column

Take a load, a length, and a trial section, and show the arithmetic that says whether the column carries it. The slenderness arithmetic is the same everywhere. The buckling curve, the factors, and the properties are not, so they come from you.

Workflow

Step 1. Establish the standard and the method

Ask, in one message:

1. Which design standard governs, and which edition?
2. Which design method: limit states with factored loads, allowable stress, partial factors, or another?
3. Material: steel, sawn timber, glulam, or reinforced concrete.
4. How will you supply values? Type them, paste the table, or name a file.

If the answer to 2 is unclear, stop; a capacity from one method against loads from another is wrong by the size of the factors.

Step 2. Collect geometry and loads

Unbraced length about each axis, and the K you assign to each, with a word on the restraint that justifies it. Loads by source, unfactored. Bracing that differs by axis is normal; bracing that is unclear stops the run.

Anything unstated is missing. Never substitute a typical value, and never assume a load is zero because it was not mentioned.

Step 3. Collect the values

Accept a typed value with its citation, a pasted table, or a file. If none arrives, the run stops at that value and says so.

Value	Needed for
Load combinations, written out	Factoring the loads
Section area and radii of gyration, both axes	Slenderness and capacity
Material strength and modulus	Capacity
The capacity expression or tabulated capacity, cited	Capacity
Resistance, safety, or adjustment factors, each named	Capacity
Slenderness limit, if your standard sets one	The slenderness check

A tabulated capacity is welcome: paste the row, name the table, and the check uses it directly, printed with its citation.

Step 4. Compute, showing every step

Loads
  <each load, as given, with units and source>
Combination used            <written out, cited>
  factored axial load       <arithmetic>
Slenderness
  KL/r, each axis           <arithmetic>
  governing axis            <which and why>
  limit (if supplied)       <as given, cited> — <pass/fail>
Capacity
  <each input, cited>
  expression, as supplied   <written out>
  capacity                  <arithmetic>
Ratio
  demand / capacity         <value>

Every input line carries where it came from. If any input is unverified, the result for that line reads unverified, not a number.

Step 5. If no trial section was given

Do not name one. Report what the demand implies instead: the capacity the section must deliver at your factors, and, where the expression allows it, the section property that capacity implies. Then say plainly to pick a section from your own tables and come back with it.

Step 6. Report

The ratio, the governing axis, the slenderness result, and the list of anything unverified. Then:

Every factor, property, and expression here came from you. I did the arithmetic and supplied no engineering values. This is a preliminary check of a braced, concentrically loaded member, and it is not a design. The Engineer of Record designs the column.

Step 7. Save, if asked

Ask whether to write the calculation to a file and where. Write it directly, including the arithmetic. There is no template and no script.

Rules

• Never supply an engineering value, and never evaluate a buckling formula you were not handed. There are none in this file.
• Never pick K. Print the user's K and their reasoning beside the result.
• Never check the axial term alone when bending exists. Interaction equation or stop.
• Confirm the design method before collecting values, and never mix methods.
• Show the arithmetic. Stop on a missing value rather than proceeding with a placeholder.
• Never convert units, and never round an input to a neater figure.
• Say on every run that this is preliminary and not a design.

Anti-patterns

• Supplying K = 1.0 as a harmless default. It is a restraint judgment, not a default.
• Recalling a column formula because the standard is familiar. Editions move; the formula comes from the user's edition or not at all.
• Naming a trial section because the load and length make it obvious.
• Running the check about one axis because the other "clearly" does not govern.
• Reporting a ratio when one of its inputs was unverified.

Resources

None. This skill is one file. Output is written directly at the path you name.