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Earthwork formulas

Surveying · FE Reference Handbook section

Surveying
5 formulas
10 exam-style examples
~55 min
All Surveying lectures

Handbook notes for this section

Definitions and conditions exactly as the handbook states them.

  • Average End Area Formula

Core formulas for this FE topic

Definitions, applicability, units, assumptions and worked examples for each relation.

Worked exam-style examples

The four ways this section is written on the real exam — thoughts first, then equations, then substitution.

Example 1
Earthwork volume by average end area

Two cross sections 30 m apart have cut areas of 24.5 m² and 31.7 m². Compute the volume between them, then the loose volume with 12% swell.

Given

  • A1=24.5m2,A2=31.7m2A_{1} = 24.5 m^{2}, A_{2} = 31.7 m^{2}
  • L=30mL = 30 m
  • Swell=12Swell = 12%

Find

Bank volume and loose (hauled) volume

Start with the thinking

  • Average end area is the FE default unless the prismoidal method is requested.
  • Swell increases hauled volume relative to bank volume.

Step-by-step solution

  1. Average area

    (24.5+31.7)/2=28.1m2(24.5 + 31.7)/2 = 28.1 m^{2}
  2. Bank volume

    V=28.1(30)=843m3V = 28.1(30) = 843 m^{3}
  3. Swell factor

    1+0.12=1.121 + 0.12 = 1.12
  4. Loose volume — 843(1.12)

  5. Result

    Vbank=843m3,Vloose=944m3V_bank = 843 m^{3}, V_loose = 944 m^{3}
Answer:

843 m³ bank, 944 m³ loose

Why the other options are there

  • 1,686 m³ (areas added, not averaged)
  • 753 m³ (shrinkage applied instead of swell)

Reference: FE Reference Handbook — Construction — Earthwork volumes

Example 2
Average-end-area earthwork volume — solve for volume — Earthwork formulas

A surveying problem uses Average-end-area earthwork volume. Given station spacing (L) = 430.0 ft; end area 1 (A1) = 397.0 ft²; end area 2 (A2) = 35.0000 ft², determine the volume (V) in ft³.

Given

  • stationspacing(L)=430.0ftstation spacing (L) = 430.0 ft
  • endarea1(A1)=397.0ft2end area 1 (A_{1}) = 397.0 ft^{2}
  • endarea2(A2)=35.0000ft2end area 2 (A_{2}) = 35.0000 ft^{2}

Find

volume (V), in ft³

Start with the thinking

  • The governing relation printed in this handbook section is Average-end-area earthwork volume.
  • Everything except V is given, so isolate V symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • Surveying items reward recognising the unknown before touching a calculator.

Step-by-step solution

  1. Step 1 — State the governing relation:

    V=L(A1+A2)/2V = L (A_1 + A_2) / 2
  2. Step 2 — Rearrange the relation so that V stands alone on the left-hand side.

  3. Step 3

    Listthegivens:stationspacing(L)=430.0ft,endarea1(A1)=397.0ft2,endarea2(A2)=35.0000ft2List the givens: station spacing (L) = 430.0 ft, end area 1 (A_{1}) = 397.0 ft^{2}, end area 2 (A_{2}) = 35.0000 ft^{2}
  4. Step 4 — Substitute the given values into the rearranged relation.

  5. Step 5 — Evaluate:

    V=92880 ft³V = 92880\ \text{ft³}
  6. Step 6 — Check: returning V = 92,880 ft³ to

    V=L(A1+A2)/2V = L (A_1 + A_2) / 2

    reproduces the given quantities, and both sides carry the same units.

Answer:
V=92880 ft³V = 92880\ \text{ft³}

Why the other options are there

  • 185,760 — kept a factor of two that cancels in the correct rearrangement.
  • 46,440 — dropped that same factor in the other direction.
  • 102,168 — rounded an intermediate value before the final step.

Reference: FE Reference Handbook — Surveying → Earthwork formulas

Example 3
Average-end-area earthwork volume — solve for station spacing — Earthwork formulas (2)

A surveying problem uses Average-end-area earthwork volume. Given end area 1 (A1) = 268.0 ft²; end area 2 (A2) = 46.0000 ft²; volume (V) = 148,838 ft³, determine the station spacing (L) in ft.

Given

  • endarea1(A1)=268.0ft2end area 1 (A_{1}) = 268.0 ft^{2}
  • endarea2(A2)=46.0000ft2end area 2 (A_{2}) = 46.0000 ft^{2}
  • volume(V)=148,838ft3volume (V) = 148,838 ft^{3}

Find

station spacing (L), in ft

Start with the thinking

  • The governing relation printed in this handbook section is Average-end-area earthwork volume.
  • Everything except L is given, so isolate L symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • Surveying items reward recognising the unknown before touching a calculator.

Step-by-step solution

  1. Step 1 — State the governing relation:

    V=L(A1+A2)/2V = L (A_1 + A_2) / 2
  2. Step 2 — Rearrange the relation so that L stands alone on the left-hand side.

  3. Step 3

    Listthegivens:endarea1(A1)=268.0ft2,endarea2(A2)=46.0000ft2,volume(V)=148,838ft3List the givens: end area 1 (A_{1}) = 268.0 ft^{2}, end area 2 (A_{2}) = 46.0000 ft^{2}, volume (V) = 148,838 ft^{3}
  4. Step 4 — Substitute the given values into the rearranged relation.

  5. Step 5 — Evaluate:

    L=948.0 ftL = 948.0\ \text{ft}
  6. Step 6 — Check: returning L = 948.0 ft to

    V=L(A1+A2)/2V = L (A_1 + A_2) / 2

    reproduces the given quantities, and both sides carry the same units.

Answer:
L=948.0 ftL = 948.0\ \text{ft}

Why the other options are there

  • 1,896 — kept a factor of two that cancels in the correct rearrangement.
  • 474.0 — dropped that same factor in the other direction.
  • 1,043 — rounded an intermediate value before the final step.

Reference: FE Reference Handbook — Surveying → Earthwork formulas

Example 4
Average-end-area earthwork volume — solve for end area 1 — Earthwork formulas (3)

A surveying problem uses Average-end-area earthwork volume. Given station spacing (L) = 385.0 ft; end area 2 (A2) = 164.0 ft²; volume (V) = 129,048 ft³, determine the end area 1 (A1) in ft².

Given

  • stationspacing(L)=385.0ftstation spacing (L) = 385.0 ft
  • endarea2(A2)=164.0ft2end area 2 (A_{2}) = 164.0 ft^{2}
  • volume(V)=129,048ft3volume (V) = 129,048 ft^{3}

Find

end area 1 (A1), in ft²

Start with the thinking

  • The governing relation printed in this handbook section is Average-end-area earthwork volume.
  • Everything except A1 is given, so isolate A1 symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • Surveying items reward recognising the unknown before touching a calculator.

Step-by-step solution

  1. Step 1 — State the governing relation:

    V=L(A1+A2)/2V = L (A_1 + A_2) / 2
  2. Step 2 — Rearrange the relation so that A1 stands alone on the left-hand side.

  3. Step 3

    Listthegivens:stationspacing(L)=385.0ft,endarea2(A2)=164.0ft2,volume(V)=129,048ft3List the givens: station spacing (L) = 385.0 ft, end area 2 (A_{2}) = 164.0 ft^{2}, volume (V) = 129,048 ft^{3}
  4. Step 4 — Substitute the given values into the rearranged relation.

  5. Step 5 — Evaluate:

    A1=506.4 ft²A_{1} = 506.4\ \text{ft²}
  6. Step 6 — Check: returning A1 = 506.4 ft² to

    V=L(A1+A2)/2V = L (A_1 + A_2) / 2

    reproduces the given quantities, and both sides carry the same units.

Answer:
A1=506.4 ft²A_{1} = 506.4\ \text{ft²}

Why the other options are there

  • 1,013 — kept a factor of two that cancels in the correct rearrangement.
  • 253.2 — dropped that same factor in the other direction.
  • 557.0 — rounded an intermediate value before the final step.

Reference: FE Reference Handbook — Surveying → Earthwork formulas

Example 5
Average-end-area earthwork volume — solve for volume (case 2) — Earthwork formulas (4)

A surveying problem uses Average-end-area earthwork volume. Given station spacing (L) = 210.0 ft; end area 1 (A1) = 260.0 ft²; end area 2 (A2) = 315.0 ft², determine the volume (V) in ft³.

Given

  • stationspacing(L)=210.0ftstation spacing (L) = 210.0 ft
  • endarea1(A1)=260.0ft2end area 1 (A_{1}) = 260.0 ft^{2}
  • endarea2(A2)=315.0ft2end area 2 (A_{2}) = 315.0 ft^{2}

Find

volume (V), in ft³

Start with the thinking

  • The governing relation printed in this handbook section is Average-end-area earthwork volume.
  • Everything except V is given, so isolate V symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • Surveying items reward recognising the unknown before touching a calculator.

Step-by-step solution

  1. Step 1 — State the governing relation:

    V=L(A1+A2)/2V = L (A_1 + A_2) / 2
  2. Step 2 — Rearrange the relation so that V stands alone on the left-hand side.

  3. Step 3

    Listthegivens:stationspacing(L)=210.0ft,endarea1(A1)=260.0ft2,endarea2(A2)=315.0ft2List the givens: station spacing (L) = 210.0 ft, end area 1 (A_{1}) = 260.0 ft^{2}, end area 2 (A_{2}) = 315.0 ft^{2}
  4. Step 4 — Substitute the given values into the rearranged relation.

  5. Step 5 — Evaluate:

    V=60375 ft³V = 60375\ \text{ft³}
  6. Step 6 — Check: returning V = 60,375 ft³ to

    V=L(A1+A2)/2V = L (A_1 + A_2) / 2

    reproduces the given quantities, and both sides carry the same units.

Answer:
V=60375 ft³V = 60375\ \text{ft³}

Why the other options are there

  • 120,750 — kept a factor of two that cancels in the correct rearrangement.
  • 30,188 — dropped that same factor in the other direction.
  • 66,413 — rounded an intermediate value before the final step.

Reference: FE Reference Handbook — Surveying → Earthwork formulas

Example 6
Average-end-area earthwork volume — solve for station spacing (case 2) — Earthwork formulas (5)

A surveying problem uses Average-end-area earthwork volume. Given end area 1 (A1) = 120.0 ft²; end area 2 (A2) = 298.0 ft²; volume (V) = 100,553 ft³, determine the station spacing (L) in ft.

Given

  • endarea1(A1)=120.0ft2end area 1 (A_{1}) = 120.0 ft^{2}
  • endarea2(A2)=298.0ft2end area 2 (A_{2}) = 298.0 ft^{2}
  • volume(V)=100,553ft3volume (V) = 100,553 ft^{3}

Find

station spacing (L), in ft

Start with the thinking

  • The governing relation printed in this handbook section is Average-end-area earthwork volume.
  • Everything except L is given, so isolate L symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • Surveying items reward recognising the unknown before touching a calculator.

Step-by-step solution

  1. Step 1 — State the governing relation:

    V=L(A1+A2)/2V = L (A_1 + A_2) / 2
  2. Step 2 — Rearrange the relation so that L stands alone on the left-hand side.

  3. Step 3

    Listthegivens:endarea1(A1)=120.0ft2,endarea2(A2)=298.0ft2,volume(V)=100,553ft3List the givens: end area 1 (A_{1}) = 120.0 ft^{2}, end area 2 (A_{2}) = 298.0 ft^{2}, volume (V) = 100,553 ft^{3}
  4. Step 4 — Substitute the given values into the rearranged relation.

  5. Step 5 — Evaluate:

    L=481.1 ftL = 481.1\ \text{ft}
  6. Step 6 — Check: returning L = 481.1 ft to

    V=L(A1+A2)/2V = L (A_1 + A_2) / 2

    reproduces the given quantities, and both sides carry the same units.

Answer:
L=481.1 ftL = 481.1\ \text{ft}

Why the other options are there

  • 962.2 — kept a factor of two that cancels in the correct rearrangement.
  • 240.6 — dropped that same factor in the other direction.
  • 529.2 — rounded an intermediate value before the final step.

Reference: FE Reference Handbook — Surveying → Earthwork formulas

Example 7
Average-end-area earthwork volume — solve for end area 1 (case 2) — Earthwork formulas (6)

A surveying problem uses Average-end-area earthwork volume. Given station spacing (L) = 285.0 ft; end area 2 (A2) = 343.0 ft²; volume (V) = 12,696 ft³, determine the end area 1 (A1) in ft².

Given

  • stationspacing(L)=285.0ftstation spacing (L) = 285.0 ft
  • endarea2(A2)=343.0ft2end area 2 (A_{2}) = 343.0 ft^{2}
  • volume(V)=12,696ft3volume (V) = 12,696 ft^{3}

Find

end area 1 (A1), in ft²

Start with the thinking

  • The governing relation printed in this handbook section is Average-end-area earthwork volume.
  • Everything except A1 is given, so isolate A1 symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • Surveying items reward recognising the unknown before touching a calculator.

Step-by-step solution

  1. Step 1 — State the governing relation:

    V=L(A1+A2)/2V = L (A_1 + A_2) / 2
  2. Step 2 — Rearrange the relation so that A1 stands alone on the left-hand side.

  3. Step 3

    Listthegivens:stationspacing(L)=285.0ft,endarea2(A2)=343.0ft2,volume(V)=12,696ft3List the givens: station spacing (L) = 285.0 ft, end area 2 (A_{2}) = 343.0 ft^{2}, volume (V) = 12,696 ft^{3}
  4. Step 4 — Substitute the given values into the rearranged relation.

  5. Step 5 — Evaluate:

    A1=−253.9 ft²A_{1} = -253.9\ \text{ft²}
  6. Step 6 — Check: returning A1 = -253.9 ft² to

    V=L(A1+A2)/2V = L (A_1 + A_2) / 2

    reproduces the given quantities, and both sides carry the same units.

Answer:
A1=−253.9 ft²A_{1} = -253.9\ \text{ft²}

Why the other options are there

  • -507.8 — kept a factor of two that cancels in the correct rearrangement.
  • -127.0 — dropped that same factor in the other direction.
  • -279.3 — rounded an intermediate value before the final step.

Reference: FE Reference Handbook — Surveying → Earthwork formulas

Example 8
Average-end-area earthwork volume — solve for volume (case 3) — Earthwork formulas (7)

A surveying problem uses Average-end-area earthwork volume. Given station spacing (L) = 395.0 ft; end area 1 (A1) = 384.0 ft²; end area 2 (A2) = 245.0 ft², determine the volume (V) in ft³.

Given

  • stationspacing(L)=395.0ftstation spacing (L) = 395.0 ft
  • endarea1(A1)=384.0ft2end area 1 (A_{1}) = 384.0 ft^{2}
  • endarea2(A2)=245.0ft2end area 2 (A_{2}) = 245.0 ft^{2}

Find

volume (V), in ft³

Start with the thinking

  • The governing relation printed in this handbook section is Average-end-area earthwork volume.
  • Everything except V is given, so isolate V symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • Surveying items reward recognising the unknown before touching a calculator.

Step-by-step solution

  1. Step 1 — State the governing relation:

    V=L(A1+A2)/2V = L (A_1 + A_2) / 2
  2. Step 2 — Rearrange the relation so that V stands alone on the left-hand side.

  3. Step 3

    Listthegivens:stationspacing(L)=395.0ft,endarea1(A1)=384.0ft2,endarea2(A2)=245.0ft2List the givens: station spacing (L) = 395.0 ft, end area 1 (A_{1}) = 384.0 ft^{2}, end area 2 (A_{2}) = 245.0 ft^{2}
  4. Step 4 — Substitute the given values into the rearranged relation.

  5. Step 5 — Evaluate:

    V=124228 ft³V = 124228\ \text{ft³}
  6. Step 6 — Check: returning V = 124,228 ft³ to

    V=L(A1+A2)/2V = L (A_1 + A_2) / 2

    reproduces the given quantities, and both sides carry the same units.

Answer:
V=124228 ft³V = 124228\ \text{ft³}

Why the other options are there

  • 248,455 — kept a factor of two that cancels in the correct rearrangement.
  • 62,114 — dropped that same factor in the other direction.
  • 136,650 — rounded an intermediate value before the final step.

Reference: FE Reference Handbook — Surveying → Earthwork formulas

Example 9
Average-end-area earthwork volume — solve for station spacing (case 3) — Earthwork formulas (8)

A surveying problem uses Average-end-area earthwork volume. Given end area 1 (A1) = 304.0 ft²; end area 2 (A2) = 133.0 ft²; volume (V) = 155,798 ft³, determine the station spacing (L) in ft.

Given

  • endarea1(A1)=304.0ft2end area 1 (A_{1}) = 304.0 ft^{2}
  • endarea2(A2)=133.0ft2end area 2 (A_{2}) = 133.0 ft^{2}
  • volume(V)=155,798ft3volume (V) = 155,798 ft^{3}

Find

station spacing (L), in ft

Start with the thinking

  • The governing relation printed in this handbook section is Average-end-area earthwork volume.
  • Everything except L is given, so isolate L symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • Surveying items reward recognising the unknown before touching a calculator.

Step-by-step solution

  1. Step 1 — State the governing relation:

    V=L(A1+A2)/2V = L (A_1 + A_2) / 2
  2. Step 2 — Rearrange the relation so that L stands alone on the left-hand side.

  3. Step 3

    Listthegivens:endarea1(A1)=304.0ft2,endarea2(A2)=133.0ft2,volume(V)=155,798ft3List the givens: end area 1 (A_{1}) = 304.0 ft^{2}, end area 2 (A_{2}) = 133.0 ft^{2}, volume (V) = 155,798 ft^{3}
  4. Step 4 — Substitute the given values into the rearranged relation.

  5. Step 5 — Evaluate:

    L=713.0 ftL = 713.0\ \text{ft}
  6. Step 6 — Check: returning L = 713.0 ft to

    V=L(A1+A2)/2V = L (A_1 + A_2) / 2

    reproduces the given quantities, and both sides carry the same units.

Answer:
L=713.0 ftL = 713.0\ \text{ft}

Why the other options are there

  • 1,426 — kept a factor of two that cancels in the correct rearrangement.
  • 356.5 — dropped that same factor in the other direction.
  • 784.3 — rounded an intermediate value before the final step.

Reference: FE Reference Handbook — Surveying → Earthwork formulas

Example 10
Average-end-area earthwork volume — solve for end area 1 (case 3) — Earthwork formulas (9)

A surveying problem uses Average-end-area earthwork volume. Given station spacing (L) = 215.0 ft; end area 2 (A2) = 153.0 ft²; volume (V) = 55,937 ft³, determine the end area 1 (A1) in ft².

Given

  • stationspacing(L)=215.0ftstation spacing (L) = 215.0 ft
  • endarea2(A2)=153.0ft2end area 2 (A_{2}) = 153.0 ft^{2}
  • volume(V)=55,937ft3volume (V) = 55,937 ft^{3}

Find

end area 1 (A1), in ft²

Start with the thinking

  • The governing relation printed in this handbook section is Average-end-area earthwork volume.
  • Everything except A1 is given, so isolate A1 symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • Surveying items reward recognising the unknown before touching a calculator.

Step-by-step solution

  1. Step 1 — State the governing relation:

    V=L(A1+A2)/2V = L (A_1 + A_2) / 2
  2. Step 2 — Rearrange the relation so that A1 stands alone on the left-hand side.

  3. Step 3

    Listthegivens:stationspacing(L)=215.0ft,endarea2(A2)=153.0ft2,volume(V)=55,937ft3List the givens: station spacing (L) = 215.0 ft, end area 2 (A_{2}) = 153.0 ft^{2}, volume (V) = 55,937 ft^{3}
  4. Step 4 — Substitute the given values into the rearranged relation.

  5. Step 5 — Evaluate:

    A1=367.3 ft²A_{1} = 367.3\ \text{ft²}
  6. Step 6 — Check: returning A1 = 367.3 ft² to

    V=L(A1+A2)/2V = L (A_1 + A_2) / 2

    reproduces the given quantities, and both sides carry the same units.

Answer:
A1=367.3 ft²A_{1} = 367.3\ \text{ft²}

Why the other options are there

  • 734.7 — kept a factor of two that cancels in the correct rearrangement.
  • 183.7 — dropped that same factor in the other direction.
  • 404.1 — rounded an intermediate value before the final step.

Reference: FE Reference Handbook — Surveying → Earthwork formulas

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