Corpus sync: neutrality remakes, note hygiene, datasheet relocation, transformer-split cross-refs
---
title: Shallow Foundations (Spread and Strip Footings)
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# Submittals {toc}
−## Action submittals are documents the Engineer of Record reviews and must accept before the related work proceeds; they establish that the contractor's intended means comply with the drawings before any concrete is placed. {note}
+## Action submittals are documents the Engineer of Record reviews and must accept before the related work proceeds; they establish that the contractor's intended means comply with the drawings before any concrete is placed.
### The Contractor shall submit the following action submittals for review and acceptance before placing footing concrete:
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## Footing depth shall satisfy the deepest of three controls: the minimum embedment below adjacent finished grade, the local frost-protection depth, and the elevation of the competent bearing stratum identified in the geotechnical report.
−## The bottom of exterior footings and footings in unheated areas shall be placed below the local frost-protection depth established by the authority having jurisdiction. {note}
−
−## Frost depth varies dramatically by region — effectively zero in the deep South to 48 inches or more across the northern tier — and a footing bottom above frost depth is subject to frost heave. The Engineer of Record translates the local frost depth into a bottom-of-footing elevation on the drawings; the contractor builds to that elevation. {note}
−
```datasheet
label: Minimum Footing Embedment Below Adjacent Grade
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```
+## The bottom of exterior footings and footings in unheated areas shall be placed below the local frost-protection depth established by the authority having jurisdiction.
+
```datasheet
label: Frost-Protection Depth (bottom of footing below grade)
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```
+## Frost depth varies dramatically by region — effectively zero in the deep South to 48 inches or more across the northern tier — and a footing bottom above frost depth is subject to frost heave. The Engineer of Record translates the local frost depth into a bottom-of-footing elevation on the drawings; the contractor builds to that elevation. {note}
+
## Where the bearing stratum is reached at a varying elevation, footings shall be stepped or deepened as directed by the Engineer of Record rather than founded partly on bearing soil and partly on fill.
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### Thickened spread footings with an integral pedestal carry a formed concrete pier between footing and steel column, common for industrial and pre-engineered metal buildings. {note}
+### The footing type shall be specified for each foundation location based on the column or wall configuration and loading it supports.
+
```datasheet
label: Footing Type
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## Horizontal reinforcement in stepped footings shall be lapped continuously across each step so that the footing acts as a single continuous element.
−# Materials {toc}
+# Footing concrete strength is selected by the Engineer of Record for structural demand and exposure; 3,000 psi is the common default for light residential work and 4,000 psi for commercial and industrial footings, with higher strengths and sulfate-resistant cement where the geotechnical report identifies aggressive soils. {note}
−## Footing concrete strength is selected by the Engineer of Record for structural demand and exposure; 3,000 psi is the common default for light residential work and 4,000 psi for commercial and industrial footings, with higher strengths and sulfate-resistant cement where the geotechnical report identifies aggressive soils. {note}
+# ACI 318-25 sets 2,500 psi as the absolute minimum for structural concrete, but durability — not strength — frequently controls the mix. Sulfate exposure classes from the geotechnical report drive cement type and supplementary cementitious materials, specified through the mix design under [[sync/cast-in-place-concrete]]. {note}
−## ACI 318-25 sets 2,500 psi as the absolute minimum for structural concrete, but durability — not strength — frequently controls the mix. Sulfate exposure classes from the geotechnical report drive cement type and supplementary cementitious materials, specified through the mix design under [[sync/cast-in-place-concrete]]. {note}
+## Footing concrete shall be normalweight ready-mixed concrete furnished and tested in accordance with ASTM C94 and [[sync/cast-in-place-concrete]].
−### Footing concrete shall be normalweight ready-mixed concrete furnished and tested in accordance with ASTM C94 and [[sync/cast-in-place-concrete]].
+## Portland cement shall conform to ASTM C150; Type I/II is the baseline, and a sulfate-resistant type shall be furnished where the geotechnical sulfate-exposure class requires it.
−### Portland cement shall conform to ASTM C150; Type I/II is the baseline, and a sulfate-resistant type shall be furnished where the geotechnical sulfate-exposure class requires it.
+## The specified compressive strength f'c shall not be less than 2,500 psi for any structural footing, in accordance with ACI 318-25.
−### The specified compressive strength f'c shall not be less than 2,500 psi for any structural footing, in accordance with ACI 318-25.
−
```datasheet
label: Specified Compressive Strength (f'c) at 28 Days
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```
−## Reinforcing bar grade is a design selection; Grade 60 deformed bar to ASTM A615 is the corpus default, with ASTM A706 low-alloy bar required where weldability or seismic ductility is specified for dowels and starter bars. {note}
+# Reinforcing bar grade is a design selection; Grade 60 deformed bar to ASTM A615 is the corpus default, with ASTM A706 low-alloy bar required where weldability or seismic ductility is specified for dowels and starter bars. {note}
−### Footing reinforcement shall be deformed bar conforming to ASTM A615 Grade 60 unless the structural drawings specify otherwise.
+## Footing reinforcement shall be deformed bar conforming to ASTM A615 Grade 60 unless the structural drawings specify otherwise.
−### Reinforcement that will be welded, or that is required to meet seismic ductility provisions of ACI 318-25 Chapter 18, shall conform to ASTM A706.
+## Reinforcement that will be welded, or that is required to meet seismic ductility provisions of ACI 318-25 Chapter 18, shall conform to ASTM A706.
```datasheet
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```
−## Lean concrete used for a mud-mat sub-base is plain, unreinforced, low-strength concrete whose purpose is to provide a clean, stable working surface for setting reinforcement — it is not a structural element. {note}
+# Lean concrete used for a mud-mat sub-base is plain, unreinforced, low-strength concrete whose purpose is to provide a clean, stable working surface for setting reinforcement — it is not a structural element. {note}
−### Lean concrete for mud-mat sub-bases shall have a specified compressive strength of 2,000 to 2,500 psi and shall be placed without reinforcement.
+## Lean concrete for mud-mat sub-bases shall have a specified compressive strength of 2,000 to 2,500 psi and shall be placed without reinforcement.
# Reinforcement, Cover, and Dowels {toc}
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−## Column and wall dowels transfer load from the superstructure into the footing and must be embedded to develop their required length; short dowels are a recurring source of field rework. {note}
+## Column and wall dowels transfer load from the superstructure into the footing and must be embedded to develop their required length; short dowels are a recurring source of field rework.
### Column and wall dowels shall match the size and number shown on the structural drawings and shall be embedded in the footing to develop their required tension or compression length per ACI 318-25.
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# Keyways and Construction Joints {toc}
−## Shear transfer between a footing and the wall or stem above it is not automatic; a keyway or a roughened, intentionally bonded construction joint must be specified, or the joint becomes a smooth plane that cannot transfer horizontal shear. {note}
+## Shear transfer between a footing and the wall or stem above it is not automatic; a keyway or a roughened, intentionally bonded construction joint must be specified, or the joint becomes a smooth plane that cannot transfer horizontal shear.
## At the footing-to-stem-wall interface, the second pour bonds to the first only as well as the joint is prepared. A formed keyway provides a mechanical shear key; alternatively, a roughened construction joint to a full amplitude provides shear-friction capacity. Dowels across the joint develop tension. The detail must be on the drawings and built as shown. {note}
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# Eccentricity and Overturning {toc}
−## Footings carrying combined axial load and moment — from frame action, wind, or seismic demand — must be checked for the bearing-pressure distribution across the base, not just the average pressure; a footing that looks adequate on average can overstress one edge or partially uplift. {note}
+## Footings carrying combined axial load and moment — from frame action, wind, or seismic demand — must be checked for the bearing-pressure distribution across the base, not just the average pressure; a footing that looks adequate on average can overstress one edge or partially uplift.
## For a footing under axial load plus moment, keeping the load resultant within the middle third of the base (eccentricity not exceeding B/6) keeps the entire base in compression. Larger moments, common in seismic design, may allow partial uplift only with a documented analysis. Footings subject to significant moment are a design responsibility, but specifications that never require the check invite undersized footings. {note}
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### The Contractor shall retain unused project-specific embed templates until final acceptance in case anchor-bolt rework is directed.