CIVL1223 Workbook 2012(2)

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2011-2012 Niagara College Dino Morabito, PQS, GSC, C.E.T.

All custom CourseWare is Non-Returnable

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Chapter 1 Earthwork

EARTHFILL DAMS

osp.mans.edu.eg Earth fill dams are constructed of massive quantities of various types of fill assembled to retain a body of water such as a river. The dam is built in such a way so that the water it is retaining will actually hold the dam in place by creating a downward pressure on the upstream side of the dam. It is usually filled with a combination of sand, soil and clay and/or rock to create an impervious base which is covered by an additional transition layer which is then covered by a rock fill or concrete surface. Our challenge as estimators is to find a way to calculate the huge volumes of fill required to fill a space that is not easily defined or categorized into standard shapes. VOLUME OF EARTHWORK

In computing volumes of earth, various cross sections of cut or fill are considered; they indicate parallel areas at definite distances apart. The volumes bounded by these areas approximate prismoids and are so considered in the computations.

The volume of earthwork may be found by means of either the AVERAGE END AREA or the PRISMOIDAL FORMULA.

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Although the former is less exact than the latter, it is generally accepted as the standard earthwork formula, on account of its simplicity.

AVERAGE END AREA FORMULA This formula is applied to areas of any shape, but the results are slightly too large. The error is small if the sections do not change rapidly, as is the usual practice. VOLUME V = A1 + A2 x L A1 & A2 = area of end sections in square

2 units L = length of solid in lineal units

Using the formula for the solid shown in Fig. 2. V = (4x6) + (5x8) x 12 = 384 m3 2 PRISMOIDAL FORMULA A prismoid is a solid whose ends are parallel and whose sides are plane or warped surfaces. VOLUME V = A1 + 4 Am + A2 x L Am = the section midway between

6 the two end bases and parallel to them. Using the formula for the solid shown in Fig. 2. V = (4x6) + (4x4.5x7) + (5x8) x 12 = 380 m3 6

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FORMULAE

AVERAGE END AREA FORMULA

V = A1 + A2 x L 2

PRISMOIDAL FORMULA

V = A1 + 4 Am + A2 x L 6

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SIMPSON’S RULE

The operation of Simpson’s Rule requires that the figure be divided into any even number of vertical or horizontal strips of uniform width (or height).

A = h/3 [first + last + 2(even) + 4(odd)]

A = h/3 [ yo + yn + 2( y2 + y4 + y6 + ………) + 4(y1 + y3 + y5 + ………) ]

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VOLUMES OF CUT OR FILL FOUND FROM CONTOURS An efficient method of computing volumes of cut and fill is to use the contours. Fig. 3 shows a portion of a plot, the contours indicating a fill. The dotted lines show the original contours and the solid lines the contours after the fill has been placed. Points a, a1, b, b1, etc., indicate the extremities of the fill. The areas between the original and

finished contours are identified as A, B, C, D, and E. Note that B and C are parallel planes, parallel faces of a solid the height of which is the vertical distance between them, actually the contour interval. If we consider the curved contours as a series of short straight lines, the earth in the solid is, approximately a prismoid. Therefore, after finding the areas A, B, etc., we can apply the “Average End Area Formula” to compute the volume of the solid. When several cross sections at equal distances are taken, it is suggested to employ SIMPSON’S RULE.

The areas A, B, C, D, E are found by digitizer and are: A = 420 m2 B = 750 m2 C = 1320 m2 D = 680 m2 E = 540 m2

Distance between contours H = 2 m

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a) Volume by Average End Area Formula Point c on contour 32 is a “point of no cut or fill”, and a section, similar to F-F, taken through point C, is a triangle, the solid in the portion of the fill being approximately pyramidal in shape, the base being area A. This same condition is found between contours 20 and 22. The volume of a pyramid is 1/3 x (base x height).

The approximate volume of the entire fill may be found by adding together the volumes of all the individual prismoids and pyramids. V= AxH + A+B x H + B+C x H + C+D x H + D+E x H + ExH 3 2 2 2 2 3 = (420x2) + (420+750)x2 + (740+1320)x2 + (1320+680)x2 + (680+540)x2 + (540x2) 3 2 2 2 2 3 = 7100 m3

b) Volume by Simpson’s Rule Simpson’s Rule covers the volume between El. 22 and El. 30.

V= H [A + E + 2xC + 4(B + D)] 3 To this the volumes of the pyramidal shaped solids between El. 30 – 32 and El. 20 – 22 have to be added.

+ AxH + ExH 3 3 Volume = H [A + E + 2xC + 4(B + D)] + AxH + ExH 3 3 3 = 2 [420 + 540 + 2x1320 + 4(750+680)] + 420x2 + 540x2 3 3 3 = 6213 + 280 + 360 = 6853 m3

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CIVIL ESTIMATING ASSIGNMENT #1 Earthwork-Computation of Volumes

Name: _________________________ Date: ____________ Answer all questions in the appropriate units.

1. Apply the “Average End Formula” and the “Prismoidal Formula” to determine the volume of excavation required given the following values.

a. Area A1 = 8.10 m x 7.70 m

Area A2 = 10.25 m x 12.10 m L = 27.75 m

b. Area A1 = 647 sf Area A2 = 460 sf L = 93 lf

2. Apply the “Average End Formula” using the following values and assuming a similar layout as shown in Fig. 3.

Area A 27.45 m² Area B 37.20 m² Area C 49.70 m² Area D 36.50 m² Area E 25.30 m² Distance between contours = 9.50 m

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3. Apply “Simpson’s Rule” using the following values and assuming a similar layout as

shown in Fig. 3.

Area A 45 sf Area B 58 sf Area C 79 sf Area D 61 sf Area E 49 sf Distance between contours = 12 lf

4. Given: Cross section through an earthfill dam; length – 300 lf Required: Cross sectional area.

Volume expressed in CY.

5. Use Simpson’s Rule to calculate the area of the irregular shaped figure.

6. Given: A0 = 345 sf A2 = 2156 sf A4 = 3390 sf A1 = 482 sf A3 = 3145 sf h = 25 lf

Required: Volume expressed in CY.

7. Given: A1 = 517 sf A2 = 312 sf Am = 416 sf L = 20 lf

Required: Find the excavation quantity.

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CIVIL ESTIMATING PRACTICE ASSIGNMENT Earthwork-Simpson’s Rule

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EARTHFILL DAMS Applied Methodology – earthwork can be calculated using the data available on drawings or site plans in a very accurate manner or it can be calculated by a faster, albeit less accurate, methodology. The choice of methodology will depend on time constraints and completeness of information provided.

1. ACCURATE METHOD: dissect shape into Horizontal or Vertical Sections, the size of the intervals being dependent on the degree of accuracy required and the time constraints.

2. FAST METHOD: using average cross sectional areas and transform into geometrical

shapes.

ACCURATE METHOD – HORIZONTAL SECTIONS

Step 1: Layout a) Indicate the boundaries of the dam by plotting contour lines at

various elevations and intersect them with the respective contours of the ground surface. The distance between sections in this example are 2 m. (See Plan showing Final Stage).

b) Plot the horizontal sections for rockfill. (See plan showing rockfill only).

c) draw a plan showing the transition material. Step 2: Digitizer Readings and Computation of Areas

For all 3 plans the same procedure is applicable. a) Find areas for the total material of the dam. b) Find areas for the rockfill portion of the dam. c) Find areas for the transition material of the dam.

Step 3: Calculation of Volumes

Compute the volumes for total material of the dam, for rockfill and for transition separately.

a) Total Volume. Volume between El. 150’ & 122’ using Simpson’s Rule (if

applicable). b) Rockfill Volume using Simpson’s Rule. c) Transition Volume using Simpson’s Rule.

Step 4: Final Volumes Volrockfill + Voltransition + Volsealing blanket = TOTAL VOLUME

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ACCURATE METHOD – VERTICAL SECTIONS

Step 1: Layout a) Construct the boundaries of the dam and locate vertical sections in

the plane. The distance between sections in this example are 16 m. b) Draw a typical cross section and indicate the ground lines of the

different vertical sections. Step 2: Digitizer Readings and Computation of Areas

Find the cross sectional areas of the different materials at the various sections.

Step 3: Calculation of Volumes

Compute the volumes for rockfill, for transition and the sealing blanket separately.

a) Rockfill. Volume west of Section 1:

V1=(S1 x ℓ1)/2

Volume between Section 1 & Section 2: V2=(S1 + S2)/2 x ℓ 2

Volume between Section 2 & Section 10 using Simpson’s Rule:

V3= ℓ/3 [S2 + S10 + 2(S4 + S6 + S8) + 4(S3 + S5 + S7 + S9)]

Volume east of Section 10: V4=(S10 x ℓ2)/2 Total Volume = V1 + V2 + V3 + V4

b) Transition Volume using Simpson’s Rule same as above. c) Sealing Blanket using Simpson’s Rule same as above.


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FAST METHOD – VERTICAL SECTIONS

Step 1: Layout Draw a typical cross section and a plan and indicate the ground lines of the different vertical sections.

Step 2: Computation of Areas

Take the average height of the dam at the established stations and calculate the areas of the various materials. If the crest width and height of the dam is known and the material has a trapezoidal shape in the cross section the following formulae are useful:

A=h[a + h/2(m-n)]

A=h[a + h/2(m+n)] Step 3: Calculation of Volumes

Similar to the Accurate Method using Vertical Sections. In this case, the areas of the various materials are calculated individually based on their shapes. It is best to use a Tabulated Calculation as per the Excel spreadsheet to organize these calculations.


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Dam @ El. 150.0m - Final Stage

Horizontal Sections

Elevation or

SectionArea of Section Units Volume Calculation

150 1,598.00 m² A0 Simpson's Rule

148 2,632.00 m² A1First Last

146 3,653.00 m² A2 A01,598.00 m² AN

190.00 m²

144 4,555.00 m² A3

142 5,300.00 m² A4 Height of Section

140 5,870.00 m² A5h= 2.00 m

138 6,120.00 m² A6

136 5,701.00 m² A7 Even Odd

134 5,245.00 m² A8 A2 3,653.00 m² A1 2,632.00 m²

132 4,181.00 m² A9 A45,300.00 m² A3

4,555.00 m²

130 3,095.00 m² A10 A6 6,120.00 m² A5 5,870.00 m²

128 2,143.00 m² A11 A8 5,245.00 m² A7 5,701.00 m²

126 1,347.00 m² A12 A10 3,095.00 m² A9 4,181.00 m²

124 615.00 m² A13 A12 1,347.00 m² A11 2,143.00 m²

122 190.00 m² AN A14 m² A13 615.00 m²

m² A16 m² A15 m²

m²

m² h/3 0.67

m² First + Last 1,788.00

m² 2 * (Even) 49,520.00

m² 4 * (Odd) 102,788.00

m²

m² V1 = 102,731 m³

m²

m²

m²

m²

m²

m²

m²

Height 2.00 m

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Dam @ El. 150.0m - Rockfill Stage

Horizontal Sections

Elevation or


150 460.00 m² A0 Simpson's Rule

148 1,390.00 m² A1First Last

146 2,170.00 m² A2 A0460.00 m² AN

190.00 m²

144 2,940.00 m² A3

142 3,550.00 m² A4 Height of Section

140 4,150.00 m² A5h= 2.00 m

138 4,347.00 m² A6

136 4,212.00 m² A7 Even Odd

134 4,022.00 m² A8 A2 2,170.00 m² A1 1,390.00 m²

132 3,312.00 m² A9 A43,550.00 m² A3

2,940.00 m²

130 2,782.00 m² A10 A6 4,347.00 m² A5 4,150.00 m²

128 2,115.00 m² A11 A8 4,022.00 m² A7 4,212.00 m²

126 1,355.00 m² A12 A10 2,782.00 m² A9 3,312.00 m²

124 608.00 m² A13 A12 1,355.00 m² A11 2,115.00 m²

122 190.00 m² AN A14 m² A13 608.00 m²

m² A16 m² A15 m²

m²

m² h/3 0.67

m² First + Last 650.00

m² 2 * (Even) 36,452.00

m² 4 * (Odd) 74,908.00

m²

m² V1 = 74,674 m³

m²

m²

m²

m²

m²

m²

m²

Height 2.00 m

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Dam @ El. 150.0m - Transition Stage

Horizontal Sections

Elevation or


150 157.00 m² A0 Simpson's Rule

148 203.00 m² A1First Last

146 277.00 m² A2 A0157.00 m² AN

80.00 m²

144 320.00 m² A3

142 387.00 m² A4 Height of Section

140 476.00 m² A5h= 2.00 m

138 453.00 m² A6

136 414.00 m² A7 Even Odd

134 352.00 m² A8 A2 277.00 m² A1 203.00 m²

132 279.00 m² A9 A4387.00 m² A3

320.00 m²

130 80.00 m² AN A6 453.00 m² A5 476.00 m²

m² A8 352.00 m² A7 414.00 m²

m² A10 m² A9 279.00 m²

m² A12 m² A11 0.00 m²

m² A14 m² A13 0.00 m²

m² A16 m² A15 m²

m²

m² h/3 0.67


m² 2 * (Even) 2,938.00

m² 4 * (Odd) 6,768.00

m²

m² V1 = 6,629 m³

m²

m²

m²

m²

m²

m²

m²

Height 2.00 m

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TOTAL VOLUME OF EARTHFILL DAM USING HORIZONTAL METHOD

Volrockfill + Voltransition + Volsealing blanket = TOTAL VOLUME

Volrockfill = 74,674 m³ Voltransition = 6,629 m³

Volsealing blanket = Volfinal stage – (Volrockfill + Voltransition) = 102,731 m³ - (74,674 m³ + 6,629 m³) = 21,428 m³

TOTAL VOLUME OF EARTHFILL DAM USING VERTICAL METHOD

Volrockfill + Voltransition + Volsealing blanket = TOTAL VOLUME

Volrockfill = 74,056 m³ Voltransition = 14,527 m³

Volsealing blanket = 10,782 m³

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Dam @ El. 150.0m - Rockfill Stage

Vertical Sections

Elevation or


1 33.27 m² Simpson's Rule


3 390.51 m² A1 A0 201.93 m² AN 13.49 m²

4 555.92 m² A2

5 752.84 m² A3Height of Section

6 929.53 m² A4 h= 16.00 m

7 813.34 m² A5

8 510.55 m² A6 Even Odd

9 219.56 m² A7 A2555.92 m² A1

390.51 m²

10 13.49 m² AN A4929.53 m² A3

752.84 m²

m² A6 813.34 m² A5 813.34 m²

m² A8 m² A7 219.56 m²

m² A10m² A9

m²

m² A12 m² A11 m²

m² A14 m² A13 m²

m² A16m² A15

m²

m²

m² h/3 5.33


m² 2 * (Even) 4,597.58

m² 4 * (Odd) 8,705.00

m²

m² V1 = 72,096 m³

m²

m²

m² Average End Area between Section 1 & 2

m² V2=(A + A)/2 x h

m²

m² V2 = 1,882 m³

m²

Height 16.00 m

Cone West of Section 1

V3=A*h/3

V3 = 55 m³

Cone East of Section 10

V4=A*h/3

V4 = 22 m³

Voltotal = V1 + V2 + V3 + V474,056 m³

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Dam @ El. 150.0m - Transition Stage

Vertical Sections

Elevation or




3 75.60 m² A1 A0 54.39 m² AN 20.85 m²

4 102.33 m² A2


6 147.26 m² A4 h= 16.00 m

7 168.71 m² A5

8 159.40 m² A6Even Odd

9 68.76 m² A7 A2 102.33 m² A1 75.60 m²

10 20.85 m² AN A4 147.26 m² A3 113.97 m²

m² A6 168.71 m² A5 168.71 m²

m² A8 m² A7 68.76 m²

m² A10m² A9

m²

m² A12 m² A11 m²

m² A14 m² A13 m²

m² A16m² A15

m²

m²

m² h/3 5.33


m² 2 * (Even) 836.60

m² 4 * (Odd) 1,708.16

m²

m² V1 = 13,974 m³

m²

m²


m² V2=(A + A)/2 x h

m²

m² V2 = 504 m³

m²

Height 16.00 m


V3=A*h/3

V3 = 14 m³


V4=A*h/3

V4 = 35 m³

Voltotal = V1 + V2 + V3 + V414,527 m³

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Dam @ El. 150.0m - Sealing Blanket

Vertical Sections

Elevation or




3 65.07 m² A1 A0 54.22 m² AN 57.14 m²

4 73.82 m² A2


6 91.16 m² A4h= 16.00 m

7 99.94 m² A5

8 95.24 m² A6 Even Odd

9 69.95 m² A7 A273.82 m² A1

65.07 m²

10 57.14 m² AN A4 91.16 m² A3 78.87 m²

m² A6 99.94 m² A5 99.94 m²

m² A8 m² A7 69.95 m²

m² A10m² A9

m²

m² A12 m² A11 m²

m² A14 m² A13 m²

m² A16m² A15

m²

m²

m² h/3 5.33


m² 2 * (Even) 529.84

m² 4 * (Odd) 1,255.32

m²

m² V1 = 10,115 m³

m²

m²


m² V2=(A + A)/2 x h

m²

m² V2 = 548 m³

m²

Height 16.00 m


V3=A*h/3

V3 = 24 m³


V4=A*h/3

V4 = 95 m³

Voltotal = V1 + V2 + V3 + V410,782 m³

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Name Date ____________

Given: The top of an earthen dam is at El. 878 metres with a level crust of 9 metres

wide. The berm slopes 1 to 2 on both of the upstream and downstream

sides. The limits of cut and fill have been shown.

Req’d: Digitize the dam to determine the total quantity of earthfill required.

Hint: Use Simpson’s Rule where applicable, otherwise work with Average End

formula and/or Prismoidal formula.

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Name Date ____________

Given: Layout of earthfill dam at alternative positions.

Req’d: Digitize each dam to determine the total quantity of earthfill required.

Determine the difference in the quantity of earthfill required to fill the two

dams.

Hint: Use Simpson’s Rule where applicable, otherwise work with Average End

formula and/or Prismoidal formula.

The roadway across the top of each dam is 4.50m wide.

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Name Date____________

Given: A missile silo site is to be built in the side of a sloped surface. Required: Calculate the quantity of cut and/or fill needed to build this site. This is a

practical application of how to apply what we have learned in this unit. Please study the drawing carefully to visualize what we are doing.

Hint: Here is how I would do this take-off:

a. Set up the scale. There is only 1 dimension noted in the description that can

be used to set the scale. The ortho function is very helpful in doing this. b. Digitize the elevations as shown. Do not worry about whether they are cut

or fill, just measure each area. Make sure that you are joining the contour lines with the new cut or fill line.

c. Be aware of Simpson’s Rule and how you can use it here. Does it work for all or part of the cut section or all of part of the fill section? Once you decide, make sure that you properly name the y-numbers in the spreadsheet so that you can easily find them when you are selecting the cells to enter into Simpson’s.

d. Make a decision on the top-most and bottom-most shape and decide what shape they are and what formula you should use to calculate them.

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Name Date____________

We are required to re-grade an existing lot to remove the low spot that is retaining water. The existing lot slopes from the N-W corner at El. 90.0m down to a low level at El. 72.0m near the S-E corner. The lot will be re-graded from El. 85.0m at the North side down to El. 76.0m at the South side. The transition line from Cut to Fill is shown on the drawing. Determine the total volumes of cut and fill required to complete the re-grading using the following methods:

1. Use the Adobe measurement tool to digitize the areas of cut and fill at each elevation and use the appropriate formulae (Simpson’s Rule, Average End, Prismoidal and/or Cone) to solve.

2. Establish the depth of cut and/or fill at each corner of the grid lines on the drawing

and use the 4 corner method to solve.

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SSeerrvviicceess

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Chapter 2 Municipal & Site Services Municipal and site services for a residential and/or commercial building are generally buried services and will include storm and sanitary sewers, water supply, gas supply, electrical and cable services. Manholes and catchbasins feed the storm water system and will be found throughout parking lots of commercial structures as well as streets and roads. This chapter will look at the take-off methodology for excavation and backfill required for the trenching for these services as well as the piping and bedding and manholes and catchbasins.

Servicing a building site will include cut & fill, excavation and backfill for the municipal services such as sanitary and storm sewer lines and the site services such as electrical and gas lines. It also includes the excavation and backfill for the building proper. When calculating the excavation quantities for cut and fill we will use the existing elevations and proposed elevations in the methodology that we covered in 1st term Construction Estimating. The building excavation and backfill was also covered in 1st term.

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The location of the manhole and catchbasin may only be shown along with their invert and finish elevations. We will often have to match the location of the service entering the building to the location of the services and make an educated assumption of the pipe run between points. A sketch is of utmost importance as we are getting our feet wet with this type of take-off. We must remember the following rules of thumb:

Always remember to consider the actual grade elevation from which we will be working. If the site calls for stripping 12” of topsoil and stockpiling on site then remember that the existing elevation will be 12” lower when we begin our services excavation.

Consider where the services are. If the manhole is in a parking lot remember to allow for the fact that we will have already excavated down to the underside of the granular material below the asphalt prior to starting the services excavation.

Remember to allow for working space in all trenching and excavation for manholes and catchbasins. The general rule-of-thumb is to allow for 600mm or 24” working space on either side of the manhole or catchbasin and to allow for 300mm or 12” on either side of the pipe in the trench.

ALWAYS consult the geotechnical report to become familiar with the soil conditions! This report will be based on borehole samples taken around the site and will inform us as to the makeup of the soil that we are digging in. The report will also advise us on the amount of swell that we can expect from the soil, if and where we may encounter rock in our excavation and what the slope of the trenching must be for safety purposes. Obviously very important information that can have a huge impact on the price of our job.

Excavations deeper than 7’ – 8’ will generally require the use of shoring and/or trench boxes. This will avoid the extensive overdigging that will be required to allow for a large slope in the trench wall.

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Precast Manholes

Precast Catchbasins

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ONTARIO PROVINCIAL STANDARDS FOR ROADS & PUBLIC WORKS http://www.raqsa.mto.gov.on.ca/techpubs/ops.nsf/OPSHomepage Civil estimators will become very familiar with the Ontario Provincial Standards or OPS. The province publishes standards that are followed by all municipalities and on all Ministry of Transportation Ontario (MTO) projects. These documents include specifications and drawings that are publically available. We will be referring to the drawings contained in Volume 3 for guidance on such information as bedding materials and depths (section 800), sizes of manholes and catchbasins (section 700), sanitary sewers (section 1000).

Terminology Invert elevation The elevation of the inside bottom of the pipe leading into a manhole or catchbasin

Sump The distance between the lowest invert elevation and the bottom of the unit. Bench In some manholes concrete will be poured around the pipe at the invert that will channel water down to the invert elevation.

Slope Trenches will use gravity to move water so will usually be sloped from their starting point to end point. The slope will generally be expressed as a % value or similar to a rise/run expression. A slope of 1/80 means that the trench will drop 1 vertical unit for every 80 horizontal units. A 1% slope will drop 1 vertical unit for every 100 horizontal units.

http://www.raqsb.mto.gov.on.ca/techpubs/OPS.nsf/OPSHomepage

http://www.raqsb.mto.gov.on.ca/techpubs/ops.nsf/wv?OpenView&Start=1&Count=1000&Expand=9&RestrictToCategory=Volume%203#9

http://www.raqsa.mto.gov.on.ca/techpubs/ops.nsf/wv?OpenView&Start=1&Count=1000&Expand=8&RestrictToCategory=Volume%203#8

http://www.raqsa.mto.gov.on.ca/techpubs/ops.nsf/wv?OpenView&Start=1&Count=1000&Expand=11&RestrictToCategory=Volume%203#11

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Municipal & Site Services Take-off Methodology As with most of our estimating we want to keep similar items together to help ensure that we don’t miss or double count items in a take-off. For a municipal take-off we will group the following items together:

1. Catchbasin & Manhole excavation. Remember to add the working space around the unit. We will usually be

given the finish surface elevation and the invert elevation. Below this we need to consider the sump, the thickness of the base, the thickness of the concrete pad (if required) and then the thickness of the granular base.

For manholes with multiple pipes entering be sure to use the lowest invert elevation.

When backfilling we deduct the volume of the catchbasin or manhole PLUS the length of pipe that runs through the working space.

2. Pipe excavation

Separate the pipes by their diameters and combine all pipes of similar diameter together. Be sure to properly describe which pipe is being calculated.

Most drawings will give the distance or length of pipe from the centerline of each unit that the pipe is connected to. To determine the quantity of excavation be sure to subtract ½ the width of the manhole at each end plus the working space.

The depth of excavation must include the slope. If slope is not given we may instead be given the invert elevation at each end, from which we can easily calculate the slope.

In addition to the depth down to the invert we must include the depth of the bedding. According to OPS we must have a minimum of 150 mm bedding below the pipe.

3. Backfill & bedding

All piping must be laid in a granular bedding. OPS generally specifies this bedding as a minimum of 150 mm below the pipe and 300 mm above the pipe. Bedding must be laid in maximum 200mm layers and compacted as it is laid.

Backfill can be made using the excavated material if the specifications allow it. Generally all pipes that are below roadways or pavements must be backfilled with granular material while excavated or ‘native’ materials are allowed to be used for backfill if the future ground surface will be sodded or landscaped.

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Sample Site Services Take-off

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CONSTRUCTION ESTIMATING VI ASSIGNMENT #6 Municipal & Site Services

Name Date

Using the attached sketch calculate the following: Volume of excavated material. Quantity of pipe required. Quantity of concrete required to pour bases for manholes and catchbasins. Volume of backfill material. Volume of excavated material for disposal or material to be purchased. Assumptions: Excavated material swells 18% and compacts 15%. Manholes are 1.50mØ (exterior) with a 1.60m x 1.60m x .25m concrete base. Catchbasins are 1.20mØ (exterior) with a 1.40m x 1.40m x .20m concrete base. Remove 300mm of topsoil prior to excavating for any site services. Allow 300mm working space to all pipe excavations (all around). Allow 600mm working space to all concrete bases (all around).

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Name Date

Using the attached drawing to calculate the following: Volume of excavated material. Quantity of pipe required. Volume of backfill material. Volume of excavated material for disposal or material to be purchased. Assumptions: Excavated material swells 18% and compacts 15%.

All backfill under pavement to be Granular A, backfill under sod is excavated (native) materials.

Catchbasins as per OPSD705.010 as noted on drawing. Invert elevation at building is minimum 13” (325mm) below fin grade (typical) to maximum 2% pipe slope to nearest CB.

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Name Date

Using the attached drawing and specifications consider the following site services:

a) Storm sewer system b) Sanitary sewer system c) Water Service

Calculate: Volume of excavated material. Quantity of pipe required. Volume of backfill material. Volume of excavated material for disposal or material to be purchased. Assumptions: Excavated material swells 18% and compacts 15%.

All backfill under pavement to be Granular A, backfill under sod is excavated materials.

Manholes and catchbasins as per OPSD standards as noted on drawing. Use precast shapes for all manholes and catchbasins. Minimum cover for water supply is 1.70 m.

Assume 375mm total depth of asphalt and granular for parking lot areas and 225mm depth of concrete and granular at sidewalk areas.

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Chapter 3 Concrete Abutments

Concrete Abutments (Stepped Footing)

A common fixture in civil construction is a concrete abutment (sometimes called a

retaining wall). These shapes are designed to provide lateral support to vertical slopes of

soil or earth. They are cast-in-place or precast concrete structures that often also provide

structural support to bridge structures. These walls also provide shoreline support in

lakefront areas.

There is considerable structural engineering that goes into the design of abutments in

order to ensure that they will effectively retain the volume of earth as well as in providing

sufficient drainage to avoid erosion. We are not concerned with the structural design

aspect, rather in the methodology to measure and calculate the quantity of concrete and

reinforcing steel required.

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Since these retaining walls must often accommodate existing earth profiles they sometimes require a stepped footing. A stepped footing is a standard concrete footing that must change elevation to accommodate a building site that is not level. A sloped building site will cause us to need to excavate a footing to a very deep level at the high end of the lot to accommodate the required footing depth at the low end of the lot UNLESS we can find a way to slope the footing and excavation. How is a stepped footing different from a standard footing from the estimator’s point of view?

Our standard method of calculating a footing is to establish the total developed length (wall perimeter) of the footing then multiply by its width and height.

In a stepped footing we need to consider that our footings will require an ‘overlap’ wherever they are stepped so we need extra concrete and formwork for this area.

Footing Overlap Where our footing steps we must ensure that the footing will properly carry the loads of the foundation walls (and structure).

Footing Step without any extra overlap concrete

To accomplish this we will overlap the footings, one over the other. As a rule of thumb the length of the overlap is equal to the thickness of the footing. To properly spread the load from the footing we will taper the overlap on a 2:1 ratio. Therefore, the length of the taper is equal to twice the difference between the bottom elevations of the two footing levels. For estimating purposes we will take off the footing in the same manner as a standard footing (wall perimeter x footing width x footing height) and add the taper wherever it occurs in the footing.

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We must also remember to add sufficient formwork to retain the concrete on the taper sides as well as a BULKHEAD to retain the footing concrete at each step.

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Sample Retaining Wall Take-off

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CONSTRUCTION ESTIMATING VI ASSIGNMENT #8 Concrete Abutments

Name Date

Using the attached drawing calculate the quantities of concrete and formwork to construct the retaining wall.

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Concrete Abutments (Wing-Walls) Concrete abutments supporting bridges are often combined with a wing-wall on either side to retain earth. Depending on the engineering these walls may be sloped and their size can be varied throughout their length. The walls will use a large footing similar to a stepped footing abutment but the footing is usually on a level grade. As the winged shape must intersect with the main abutment wall we will have to consider a more complicated mathematical calculation. We will use much of what we have learned, including average end area and prismoidal formulas.

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Sample Wing Wall Take-off

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CONSTRUCTION ESTIMATING VI ASSIGNMENT #9 Highway Overpass

Name Date Using the attached drawing calculate the quantities of concrete and formwork to construct the concrete wing-wall abutments.

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CONSTRUCTION ESTIMATING VI ASSIGNMENT #10 Highway Overpass

Name Date Using the previous drawing calculate the quantities of concrete and formwork to construct the concrete overpass.

CIVL1223 Workbook 2012(2)

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Transcript of CIVL1223 Workbook 2012(2)