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The total factored uplift (tension) load the baseplate connection must resist.
The net uplift after dead load has been counted against it, factored to match the anchor design method. Wind uplift on a light structure is frequently the governing case and the one that decides anchor size, and the dead load offsetting it must be the reliably present part rather than everything on the drawing. Overturning from a moment produces tension in the anchors on one side and is not the same thing as net uplift.
The lowest governing rated tensile capacity for a single anchor, per ACI 318 Chapter 17.
Compare steel strength, concrete breakout, and pullout capacities per ACI 318 Chapter 17 and use the lowest (governing) value here.
The baseplate's plan (footprint) area.
The plate's own plan area, used here for the grout volume — so it is the area to be filled under the plate rather than a bearing area with anything deducted. Include the area under the anchor pockets if they are grouted with the bed; exclude any area outside the plate that the grout will spread to, which is waste rather than volume.
The thickness of the leveling grout pocket beneath the baseplate.
The gap between the underside of the plate and the concrete, set by the levelling nuts or shims. It is usually 25 to 50 mm: thick enough to place and flow, thin enough that the grout is not doing structural work it was not designed for. The thickness drives the volume linearly and the volume is small, so a modest pocket depth mis-read is a bag or two rather than a disaster — but a pocket too thin to fill leaves voids under the plate, which is.
Anchor bolts needed
4 anchors
Use the lowest governing rated tensile capacity for your specific anchor (steel strength, concrete breakout, or pullout per ACI 318 Chapter 17) — not an assumed value. AISC Design Guide 1 covers full baseplate/anchor rod design.
- Grout pocket volume
- 3.62 gal
They open the calculator with your figures already in it
Baseplate Anchor Bolt Count & Grout Pocket Volume Calculator: 4 anchors — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
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How this was calculated
Formula source(s)
- Anchor bolt tension is governed by the lowest of several ACI 318 Chapter 17 strength limit states (steel strength, concrete breakout, pullout) — this calculator divides the total required uplift load by your own anchor's governing rated tensile capacity; grout pocket volume follows AISC Design Guide 1 practice: plate footprint × grout thickness
Inputs used
- Total Required Uplift/Tension Load
- 44.96 kip
- Per-Anchor Governing Rated Tensile Capacity
- 11.24 kip
- Baseplate Area
- 3.88 sq ft
- Grout Pocket Thickness
- 1.5 in
Intermediate steps
- Grout pocket volume
- 3.62 gal
Confidence note: Use the lowest governing rated tensile capacity for your specific anchor (steel strength, concrete breakout, or pullout per ACI 318 Chapter 17) — not an assumed value. AISC Design Guide 1 covers full baseplate/anchor rod design.
What this calculation does not cover
- Dividing one total by one anchor's capacity assumes every rod pulls the same. A column base carrying moment does not work that way: the axial load and the moment together decide the tension, and it lands almost entirely on the rods to one side of the plate, so a group sized on a shared total can be two rods short where it counts and two rods idle where it does not.
- Says nothing about setting the rods. Anchor rods are cast before the column exists, located off a template, and the tolerance they have to land within is tight — a group placed out of position is the commonest problem on a steel job, and the remedy (oversized plate washers, a replacement plate, field welding) is an engineering decision rather than a site one, because it changes the load path the count assumed.
- The grout figure is a pocket volume, not an order. Bagged non-shrink grout is sold against a yield quoted at a stated consistency, and a flowable mix yields differently from a plastic one, so the volume converts to bags only through that product's own table — and the pocket has to be filled from one side with a head behind it, because a void left under a plate is exactly the bearing area the column was sized on.
Estimated cost — your price
This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.
Computed in your browser — nothing you enter is uploaded. Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.
Sources checked 2026-09-06 · in the site-wide review of 2026-09-06 · v1.0.1
Regulatory standards & verification citations1
- Anchor bolt tension is governed by the lowest of several ACI 318 Chapter 17 strength limit states (steel strength, concrete breakout, pullout) — this calculator divides the total required uplift load by your own anchor's governing rated tensile capacity; grout pocket volume follows AISC Design Guide 1 practice: plate footprint × grout thickness
Which documents these citations point at
Standards referenced: ACI 318 (American Concrete Institute, United States).
Cite this page
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