2007 PICE NATIONAL CONVENTION

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ONE-SIDE SLOPE ROAD: Alternative Scheme to Cut Cost

in Urban Road Projects

HENRY P. TURALDECollege of Engineering

Camarines Sur Polytechnic CollegesEmail: engineer_pluss@yahoo.com

Quotable Quotes

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“A man’s judgment is no better than his information”

- Bits and Pieces

Outline of the presentation

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Introduction The Typical Cross-section

Common Scheme : Cross Slope Alternative Scheme: One Side

Slope Designing the Storm Water Drainage

Using Box Culvert Using Pipe Culvert

Highlights on the Differences of the Common and Alternative Schemes

Conclusion

Introduction

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Land transportation Principal means of

transporting persons and goods

Road’s crucial role in economic development

Roads as priority infrastructure

Introduction

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THE PROBLEMCost – major

constraint in construction of road projects Materials Labor Equipments

Introduction

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Cost reduction considerations, one or combination as appropriate: Do away with non-essentials Eliminate duplicates Rid off redundant Reduce items of works Combine similar works Others

The Typical Cross Section

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slope slopeslope

slope

carriageway

drainage drainage

sidewalk sidewalk

Common Scheme:

Two-side slope or cross-slope

two drainage lines

The Typical Cross Section

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slope slopeslope

slope

carriageway

drainage drainage

sidewalk sidewalk

Common Scheme:

Two-side slope or cross-slope

two drainage lines

The Typical Cross Section

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slope

slope

slope

carriageway

drainage

sidewalksidewalk

Alternative Scheme:

One-side slope

one drainage line

(bigger)

Designing the Road’s Storm-Water Drainage

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where: Q = run-off rate C = coefficient of run-off I = average rainfall intensity Ad = drainage area

AdCIQ SRnv 21

32

)1(

where: v = flow velocity n = Manning’s roughness

coefficient S = slope R = hydraulic radius

)1( nQ Ac SR 2

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2

where: Ac = cross-sectional area of flow

Designing the Road’s Storm-Water Drainage

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Ac = 0.7653 D2

P = 2.639 DR = Ac/P = 0.7653D2/2.639D = 0.29D

Ac = bd = 2d2 P = 2d + b = 2d + 2d = 4dR = Ac / P = 2d2 / 4d = ½ d

Using Box Culvert: Using Pipe:

Designing the Road’s Storm-Water Drainage

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Illustrative Example ApplicationGiven:

Length of the Road = 1000 m Width of the 2-lane road = 7 m

(consider 20 m including sidewalk, planting strip and other)

Distance between manholes = 50 m Coefficient of run-off = 0.85 Rainfall intensity = 224 mm/hr = 0.0622 mm/sec Roughness coefficient = 0.013 Slope = 0.005

Dimension of drainage linesUsing box culverts

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Sta. up to Drain. AreaUse 2 culverts w/ dimension

(mm)Use 1 culvert w/ dimension

(mm)

km m2 b d b d

0 + 050 1,000 500 500 600 500

0 + 100 2,000 600 500 700 500

0 + 150 3,000 600 500 700 500

0 + 200 4,000 700 500 800 500

0 + 250 5,000 700 500 800 500

0 + 300 6,000 700 500 800 500

0 + 350 7,000 750 500 800 500

0 + 400 8,000 750 500 900 600

0 + 450 9,000 750 500 900 600

0 + 500 10,000 800 500 900 600

0 + 550 11,000 800 500 900 600

0 + 600 12,000 800 500 900 600

0 + 650 13,000 800 500 900 600

0 + 700 14,000 800 500 1,000 600

0 + 750 15,000 850 500 1,000 600

0 + 800 16,000 850 500 1,000 600

0 + 850 17,000 850 500 1,000 600

0 + 900 18,000 850 500 1,000 600

0 + 950 19,000 900 500 1,000 600

1 + 000 20,000 900 500 1,000 600

Using box culverts

Typical detail of box culvert excavation

O.D. + 0.6m

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Dimension of drainage linesusing pipes

15Sta. up to Half-Q Diameter Use 2 pipes Full- Q Diameter Use 1 pipe

km m3/sec mm mm m3/sec mm mm

0 + 050 0.026 204 200 0.053 265 300

0 + 100 0.053 265 300 0.106 344 400

0 + 150 0.079 271 300 0.159 351 400

0 + 200 0.106 344 400 0.212 446 500

0 + 250 0.132 374 400 0.264 485 500

0 + 300 0.159 400 400 0.317 519 600

0 + 350 0.185 424 500 0.370 550 600

0 + 400 0.212 446 500 0.423 578 600

0 + 450 0.238 466 500 0.476 604 600

0 + 500 0.264 485 500 0.529 629 700

0 + 550 0.291 502 500 0.582 652 700

0 + 600 0.317 519 600 0.635 673 700

0 + 650 0.344 535 600 0.688 694 700

0 + 700 0.370 550 600 0.740 713 800

0 + 750 0.397 564 600 0.793 732 800

0 + 800 0.423 578 600 0.846 750 800

0 + 850 0.450 591 600 0.899 767 800

0 + 900 0.476 604 600 0.952 784 800

0 + 950 0.502 617 700 1.005 800 800

1 + 000 0.529 629 700 1.058 815 900

Using pipes

Typical detail of pipe culvert excavation

OD + 0.6m

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Benefits of the Alternative Scheme

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slope

slope

slope

carriagewaysidewalksidewalk

Typical Cross-Section

One-Side Slope Road

Summary Comparison Quantities of drainage works

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No. of Manholes = 2 [(1000/50) + 1] = 42

No. of Manholes = (1000/50) + 1 = 21

Manholes reduced = 42 -21 = 21 (50%)

For cross-slope:

For one-side slope:

2007 PICE NATIONAL CONVENTION

Benefits of the Alternative Schemeusing box culvert

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slope

slope

slope

carriageway

drainage

sidewalksidewalk

Typical Cross-Section

One-Side Slope Road

Summary Comparison Quantities of drainage works

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USING BOX CULVERTS

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Excavation (m3) Backfill (m3) Concrete (m3) Steel (kg)

 Cross-slope 4,322.50 2,622.50 937.50 84,375.00

 One-side slope 2,493.13 1,428.25 562.88 50,658.75

Qty. Reduced 1,829.37 1,194.25 374.62 33,716.25

Reduced (%) 42.32% 45.54% 39.96% 39.96%

Benefits of the Alternative Schemeusing pipes

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slope

slope

slope

carriageway

drainage

sidewalksidewalk

Typical Cross-Section

One-Side Slope Road

Summary Comparison Quantities of drainage works

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USING PIPES

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Excavation (m3) Backfill (m3) 

Cross-slope 2,256.00 1,827.96

 One-side slope 1,463.00 1,111.14 

Quantity reduced 793.00 716.82 

Reduced (%) 35.15% 39.21%

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Diameter Cross-slope One-side Slope Reduction

(mm) Length (m) Length (m) Length (m) %200 100 - 100 100.00%300 200 50 150 75.00%400 300 100 200 66.67%500 500 100 400 80.00%600 700 200 500 71.43%

700 200 200 0 0.00%

800 - 300(300

addition) -

900 - 50 (50 addition) -Total 2000 1000 1000 -

Summary Comparison Quantities of drainage works

USING PIPES

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CONCLUSION

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One-side slope road as alternative scheme cuts down urban road project construction costs due to reduction of quantities of drainage works Excavation Backfill Manholes Conveyance materials

One-side slope road shortens project execution period Particularly underground works require extra

care Savings derived through this alternative scheme

Eventually be used to build other roads

Point to Ponder

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In time of scarcity, option is a luxury.

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THANK YOU.

HENRY P. TURALDEEmail: engineer_pluss@yahoo.com