Dynamic Excel Calculator for Biaxial Eccentricity, Footing Kern Analysis, Soil Contact Pressure, Partial Contact, Uplift & Preliminary Foundation Sizing.

Analyze soil bearing pressures beneath rectangular and square pad footings with a professional 22-sheet Excel engineering calculator.

Evaluate concentric and eccentric loading, biaxial moments, footing kern limits, partial soil contact, uplift conditions, and preliminary foundation dimensions through interconnected calculations and dynamic visualizations.

Includes a 21-page technical field guide, worked engineering examples, and calculation verification controls.

Designed for structural, civil, geotechnical, and foundation engineers.

Format: Excel XLSX + PDF Field Guide + README

Compatibility: Microsoft Excel 365 required for biaxial partial-contact calculations.

PAD FOOTING & COLUMN BASE SOIL BEARING PRESSURE EVALUATOR

Professional Excel Engineering Calculator + Technical Field Guide

Understand Your Foundation's Soil Contact Behavior Before Final Design

A pad footing subjected to axial loads and bending moments rarely experiences perfectly uniform soil pressure.

As the load resultant moves away from the footing centroid, soil pressure becomes nonuniform. Under sufficiently eccentric loading, part of the footing may lose contact with the supporting soil.

Traditional uniform-pressure calculations cannot fully describe these conditions.

The Pad Footing & Column Base Soil Bearing Pressure Evaluator provides a structured, calculation-driven workflow for examining shallow foundation bearing behavior under concentric loading, uniaxial eccentricity, and simultaneous biaxial moments.

Built around a professional 22-worksheet Excel calculation system, the toolkit helps engineers visualize the load resultant, identify footing kern boundaries, evaluate compression-only contact pressures, and compare calculated bearing demands against appropriately defined geotechnical allowable values.

WHAT MAKES THIS TOOLKIT DIFFERENT?

1. Dynamic Footing Kern Analysis

Identify where the vertical load resultant acts relative to the footing centroid and the rectangular no-tension kern.

The calculator evaluates the combined biaxial kern condition rather than relying on separate one-axis middle-third checks.

2. Concentric & Eccentric Bearing Calculations

Evaluate:

• Concentric axial compression

• Uniaxial eccentric compression

• Biaxial eccentric compression

• Positive and negative moment directions

• Full-contact corner pressures

• Maximum and minimum theoretical pressure

3. Compression-Only Partial Contact Analysis

When eccentricity causes the theoretical full-contact pressure distribution to become tensile, the calculator distinguishes the invalid full-contact assumption from a physically meaningful compression-only contact model.

It includes analytical uniaxial triangular-contact calculations and an iterative, equilibrium-checked numerical solver for the selected biaxial partial-contact case.

4. Dynamic Engineering Visualizations

Explore formula-driven representations of:

• Footing geometry and centroid

• No-tension kern boundary

• Applied load resultant

• Soil bearing-pressure distribution

• Compression contact regions

• Reduced contact and zero-pressure areas

The visualizations are schematic engineering aids, not finite-element or survey-scale drawings.

5. Bearing Pressure & Geotechnical Review

Compare modeled bearing demands against project-specific allowable soil bearing values using an explicitly selected gross or net comparison basis.

The workbook also provides a separate effective-area calculation, with clear distinctions between equivalent effective-area pressure and modeled maximum contact pressure.

6. Preliminary Footing Size Evaluation

Review 12 preliminary footing dimension scenarios to investigate changes in footing geometry, bearing response, eccentricity, and contact classification.

Cases requiring an additional biaxial partial-contact solution are identified instead of receiving unsupported results.

7. Engineering QA & Calculation Transparency

Review linked calculation steps, equilibrium residuals, solver convergence, numerical examples, load-case status, uplift warnings, and outstanding engineering checks.

The workbook is designed to support a transparent engineering review process rather than operate as an unexplained black-box calculator.

WHAT YOU RECEIVE

22-Sheet Excel Engineering Calculator (.XLSX)

An interconnected workbook featuring geometry, load cases, load transfer, pressure calculations, contact analysis, sizing scenarios, visualizations, and quality-control checks.

21-Page Professional Engineering Field Guide (.PDF)

A technical reference containing 82 numbered sections covering foundation bearing principles, governing formulas, eccentric loading, worked examples, numerical verification, field observations, and engineering limitations.

Technical README (.MD)

Instructions covering workbook operation, compatibility, calculation conventions, numerical methods, assumptions, and buyer licensing.

All three files are provided in a single downloadable ZIP package.

WHO IS THIS FOR?

• Structural engineers and design consultants

• Civil and foundation engineers

• Geotechnical engineering professionals

• Engineering calculation reviewers

• Foundation feasibility teams

• Engineering offices evaluating isolated shallow foundations

• Junior engineers working under qualified supervision

SOFTWARE REQUIREMENTS

Microsoft Excel 365 is required for the formula-driven biaxial partial-contact solver.

No VBA macros, external Python runtime, paid Excel add-ins, or cloud calculation service are required for the delivered workbook.

IMPORTANT ENGINEERING SCOPE

This is a preliminary foundation contact and allowable-pressure evaluation tool, not a complete foundation design system.

It does not independently verify settlement, sliding, global stability, concrete flexure, one-way shear, punching shear, reinforcement, local steel-column base-plate bearing, or project-specific design-code compliance.

User-supplied geotechnical values, loading assumptions, and engineering conditions require professional verification before use on actual projects.

Build more transparent foundation calculations. Visualize eccentric loading. Evaluate compression-only soil contact. Document your preliminary bearing checks.

Get the complete engineering toolkit.

Key Product Features

✓ 22 interconnected Excel engineering worksheets

✓ 12 selectable concurrent load cases

✓ Concentric, uniaxial & biaxial bearing analysis

✓ Dynamic footing kern and resultant visualization

✓ Full-contact corner pressure calculations

✓ Uniaxial triangular partial-contact analysis

✓ Numerical biaxial compression-only contact solver

✓ Contact area and maximum pressure evaluation

✓ Horizontal load and moment transfer calculations

✓ Gross and net allowable bearing comparisons

✓ Separate effective-area bearing approximation

✓ Uplift and loss-of-contact warnings

✓ 12 preliminary footing sizing scenarios

✓ Formula-driven 21 × 21 soil-pressure visualization

✓ Calculation trace and engineering QA checks

✓ SI and US customary input options

✓ 21-page technical field guide

✓ No VBA macros or paid add-ins

What's Included?

COMPLETE DIGITAL ENGINEERING PACKAGE

1. Excel Engineering Calculator — 22 worksheets (.XLSX)

2. Engineering Field Guide — 21 pages (.PDF)

3. Technical README & Instructions (.MD)

4. Complete Download Package (.ZIP)

Product Version: 1.0

Edition: First Edition, 2026

Author: Mohammed A. Omer

Publisher: Sarchawa — sarchawa.com

Delivery Format: Digital Download

Physical Product: None

Product Benefits

Visualize the Load Resultant

See how eccentricity affects the relationship between the applied load resultant, footing geometry, and the no-tension kern.

Understand Soil Contact Conditions

Distinguish full contact from partial compression contact and identify conditions where compression-only soil reaction cannot maintain equilibrium.

Review Biaxial Foundation Loading

Evaluate simultaneous moments acting about both footing plan axes rather than relying only on simplified one-direction calculations.

Explore Preliminary Foundation Sizes

Investigate footing geometry alternatives and recognize cases requiring additional contact analysis.

Improve Calculation Traceability

Follow linked formulas, numerical solver residuals, bearing utilization, and engineering QA warnings in a structured workbook.

Support Professional Engineering Review

Organize preliminary soil-bearing checks into a consistent, reviewable calculation workflow.

Software Compatibility

Required Software: Microsoft Excel 365 & Google Workspace

File Format: XLSX

Macros: Not Required

Paid Add-ins: Not Required

External Calculation Software: Not Required

Biaxial Solver: Uses Excel LET formulas, array-enabled SUMPRODUCT, and numerical iteration.

Unit Systems: SI and US customary input modes.

Important: Choose the unit system before entering values. Switching unit modes does not automatically convert existing hardcoded entries.

Full compatibility with older Microsoft Excel versions, Google Sheets, or LibreOffice has not been independently verified.

The downloadable field guide is supplied in PDF format.

Frequently Asked Questions

Q: Is this a complete reinforced concrete footing design tool?

No. It evaluates preliminary soil bearing and footing contact behavior. Concrete flexure, punching shear, one-way shear, reinforcement design, settlement, and other necessary checks are outside its implemented scope.

Q: Does the calculator support biaxial bending moments?

Yes. The workbook evaluates full-contact biaxial pressure distributions and includes a numerical compression-only solver for the selected biaxial partial-contact case.

Q: Can it analyze footings with partial uplift or loss of soil contact?

Yes. The calculator identifies partial-contact conditions and estimates contact pressures within its implemented model. It also flags nonpositive vertical loads and resultants outside the footing boundary where the compression-only bearing model cannot provide equilibrium.

Q: Does the Excel file update when I change the inputs?

The workbook uses interconnected formulas designed to recalculate when compatible inputs change. The biaxial partial-contact solver requires Microsoft Excel 365. Full execution in a desktop Excel installation has not been independently verified.

Q: Can I use this for any footing shape?

No. Its primary contact calculations apply to rectangular and square isolated pad footings with horizontal planar bearing surfaces.

Q: Does the calculator provide allowable soil bearing capacity?

No. The appropriate allowable bearing pressure must be obtained from a verified geotechnical investigation or other applicable project-specific engineering source.

Q: Can I compare several footing dimensions?

Yes. The workbook provides 12 preliminary sizing scenarios. Biaxial partial-contact candidates requiring independent numerical solutions are flagged until individually analyzed.

Q: Are both metric and imperial units available?

Yes. SI and US customary input modes are available. Existing input values are not automatically converted when switching unit modes.

Q: Are macros or paid add-ins required?

No. The delivered XLSX uses standard Excel workbook formulas, including modern Excel functions.

Q: Is this suitable for construction approval?

No. The results require applicable geotechnical and structural design checks, independent professional review, and confirmation of the governing design requirements.

Engineering Disclaimer

This product is intended for preliminary structural and geotechnical engineering analysis, calculation support, and professional education.

It is not a substitute for project-specific geotechnical investigations, structural foundation design, independent engineering verification, or approval by qualified licensed professionals where required.

The calculator does not independently establish settlement performance, ultimate soil bearing resistance, foundation sliding capacity, overall stability, reinforced concrete structural adequacy, or compliance with any specific building code.

Numerical calculation results depend on the supplied geometry, loads, material assumptions, allowable bearing values, modeling limits, and solver validity.

All demonstration values are fictional and must not be used as approved construction data.

Digital Product License

Copyright © 2026 Mohammed A. Omer. All rights reserved.

Published by Sarchawa — sarchawa.com.

Purchase grants permission to use the supplied digital resources for the buyer's internal preliminary engineering work, professional reference, and calculation-review activities.

Redistributing, reselling, republishing, sublicensing, or rebranding the supplied workbook, field guide, or substantially unchanged digital package as a competing product is prohibited without written authorization.

Purchase does not transfer ownership of the original published materials.