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Cantilever Retaining Wall Dimensions Calculator

Cantilever reinforced concrete retaining walls require balanced footing geometry to prevent sliding kickout, toe crushing, and overturning failure.

Clear vertical height of the stem from footing top to ground surface (typically 1.5 to 8.0 m).

Effective angle of internal shearing resistance for the granular backfill (typically 28° to 38°).

Moist bulk unit weight of the backfill soil (typically 17 to 20 kN/m³).

Safe allowable soil bearing capacity of the foundation ground.

Live load surcharge acting on backfill surface (highway traffic is typically 10 to 15 kPa).

Calculated Result
2.91 m

Recommended Footing Base Width (B)

Recommended Base Width (B)

2.91 m (9.55 ft)

Heel Slab Width

1.43 m

Toe Slab Projection

0.97 m

Footing Thickness

0.6 m (600 mm)

Stem Base Thickness

510 mm

Sliding Safety Factor

0.95:1 (Key required)

Calculation Breakdown

  1. Rankine Active Earth PressureKa = tan²(45° - 32°/2) = 0.307
  2. Footing & Base Width SizingTotal H ≈ 4.5m + 0.6m = 5.10m → B ≈ 0.55 × H_total = 2.91m
  3. Heel and Toe Layout ProportionsToe = B / 3 = 0.97m, Stem Base = 510mm, Heel = 1.43m

Retaining Wall Geometry Proportions (m)

Interactive visualization based on your current inputs

Dimension
0.01.12.33.44.5Stem HeightTotal Base WidthToe WidthHeel WidthBase ThicknessComponentDimension (m)

What Is the Cantilever Retaining Wall Dimensions Calculator?

The Cantilever Retaining Wall Dimensions Calculator sizes the foundational proportions of reinforced concrete cantilever walls.

How Does the Cantilever Retaining Wall Dimensions Calculator Work?

It combines Rankine active earth pressure analysis with empirical ACI proportioning criteria to calculate base slab width, toe width, heel width, and stem thickness.

Cantilever Retaining Wall Dimensions Calculator Formula & Variables

The core mathematical equation utilized by this calculator is expressed as:

B \approx (0.50 \sim 0.70) H, \quad B_{toe} \approx B / 3, \quad t_{base} \approx H / 10

Empirical proportioning combined with Rankine active thrust equilibrium ensuring overturning and bearing safety.

How to Use the Cantilever Retaining Wall Dimensions Calculator

  1. Enter exposed stem height above footing.
  2. Specify backfill soil friction angle and unit weight.
  3. Input allowable bearing pressure and traffic surcharge.

Step-by-Step Example Calculation

4.5-Meter Highway Cantilever Wall

Input Values:

stemHeightM:4.5
soilFrictionAngleDeg:32
soilUnitWeightKNPerM3:18.5
allowableSoilBearingKPa:200
groundSurfaceSurchargeKPa:10
Worked Steps: Generates a 2.85 m base slab with 0.95 m toe projection and 450 mm base thickness.

Understanding Your Result

Recommended Base Width: Total width of the reinforced concrete footing slab.

Toe & Heel Widths: Respective front and back projections from the stem faces.

Sliding Safety Factor: Initial check on lateral sliding stability.

Factors That Affect the Result

  • Steeper friction angles reduce lateral thrust, allowing narrower footings.
  • High surcharges increase overturning moment and demand wider heel projections.

When Should You Use This Calculator?

  • Preliminary structural sizing, earth retaining schemes, and civil site grading designs.

Assumptions & Limitations

  • Assumes level backfill surface and non-cohesive granular backfill with proper weep hole drainage.

Frequently Asked Questions

Calculation Accuracy & Reference Note

Based on standard ACI 318 and Bowles Foundation Analysis and Design guidelines.

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