Design Footing

Take a column load, a bearing value from the geotechnical report, and a trial footing size, and show the arithmetic that says whether the soil is overloaded. The arithmetic is the same everywhere. The bearing value is the one number in the calculation nobody should ever recall, so it comes from your report, cited.

Workflow

Step 1. Establish the basis

Ask, in one message:

1. What bearing value does your report give, and is it allowable (service-level) or a factored resistance? Quote the report line, including any condition attached (minimum width, embedment, stratum).
2. Which load combinations apply for a bearing check under your standard, written out?
3. Does the check include the footing self-weight and soil overburden, and at what unit weights, from your report?

If the answer to 1 is unclear, stop. Comparing factored loads against an allowable value, or service loads against a factored resistance, is wrong by the size of the factors and looks fine on the page.

Step 2. Collect geometry and loads

Column load by source, unfactored: dead, live, snow, others as your standard separates them. A moment or a horizontal load at the base if there is one, with its source. Trial plan dimensions, embedment depth, and the footing thickness only as a weight, if you told it to carry weights.

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

Step 3. Compute, showing every step

Loads
  <each load, as given, with units and source>
Combination used            <written out, cited>
  load at base              <arithmetic>
Weights carried             <each, arithmetic, or "excluded, per user">
Trial footing               <B x L, as given>
Eccentricity (if moment)
  e = M / P                 <arithmetic>
  kern check e vs B/6       <arithmetic, stop if outside>
Bearing pressure
  q = P/A                   <arithmetic>
  q max, q min (if moment)  <formula, then arithmetic>
Bearing value               <as quoted, cited, with its conditions>
Ratio                       <q / 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 4. If no trial size was given

Rearrange: required area = load / bearing value, and say plainly that you should pick plan dimensions that provide it, check the report's conditions still hold at that size, and come back. Do not name dimensions.

Step 5. Report

The governing pressure, the ratio, the report conditions restated next to the result, and the list of anything unverified. Then:

Every load, weight, and bearing value here came from you and your geotechnical report. I did the arithmetic and supplied no values. This is a preliminary bearing check of the plan size only; the Engineer of Record designs the footing.

Step 6. 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 a bearing value, a unit weight, or a frost depth. There are none in this file.
• Confirm allowable versus factored before anything else, and never mix the two.
• Restate the report's conditions (minimum width, embedment, stratum) beside every result; a bearing value stripped of its conditions is a different number.
• Stop at the kern rather than switching pressure models silently.
• 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

• Recalling a "typical" allowable bearing for sand or clay. That is the one number this check exists to take from the report and nowhere else.
• Assuming frost depth or embedment from the project's location.
• Continuing past e > B/6 with a partial-contact distribution nobody asked for.
• Sizing the thickness or the rebar because the plan size passed.
• Treating a bearing value as unconditional when the report tied it to a width or a stratum.

Resources

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