Objectives

Introduction

Open-cut Installation

Horizontal Directional Drilling Installation

Advantages of HDD vs. Open-cut

Social Cost

Project Description

Cost Comparison

Cost Summary

Conclusion

• Cost comparison of:

Horizontal Directional Drilling (HDD) with traditional

open-cut.

Actual HDD projects carried with theoretical open-cut

costs.

• Summarizing the cost comparison results based on

Contractor’s Bid and RS Means Cost Data 2010.

The cost effective

construction of a pipeline

project requires a clear

understanding of all cost

factors associated with the

specific project conditions.

Cost of a Project

The costs of new installation of water pipes depend on

many factors like the:

Project Size

Length

Depth

Location

Surface and Subsurface Conditions

Type of Application, etc

Work items:

Pipe transportation, handling,

and storage.

Trench excavation.

Foundation, bedding and

placing, and joining of pipe.

Embedment, backfill, and

compaction of the soil.

Costs associated withexcavation, backfilling andresurfacing can account toas high as 70% of the totalproject cost (Najafi, 2005)

Method of installing underground pipes and conduits

along a prescribed bore path from the surface

Minimal impact to the surrounding area.

Task Mini Rigs Midi Rigs Maxi Rigs

Mobilization and Set up < 6 hrs 1 – 3 days 3 – 10 days

Pilot Hole Drilling 100 – 400 ft/hr 60 – 300 ft/hr 20 – 180 ft/hr

Pre-reaming/Reaming (Per

Pass)100 – 300 ft/hr 60 – 240 ft/hr 20 – 180 ft/hr

Product Pullback 200 – 600 ft/hr 200 – 600 ft/hr 150 – 450 ft/hr

Cleanup and Demobilization 2 – 4 hrs 4 hrs to 2 days 2 – 7 days

Trenchless Technology

vs.

Open-Cut Method

Social 5%

Indirect /overhead

20%

Labor 40%

Material 35%

Trenchless Costs

Social 40%

Labor 30%

Materials 10%

Indirect /overhead

20%

Open-cut Costs

Najafi & Gokhale, 2005

Parameters Open-cut InstallationHorizontal Directional

Drilling Installation

Installation costs Installation can be expensive in urban areas Cost effective method in urban areas

Social costsHigh cost for noise, safety, damage to nearby

structures and utilities, health & business loss

Less noise, minimum health risk, no

obstruction to business

Indirect costs Traffic control, job site cost is highMinimum excavation, less traffic

congestion, and minimum equipment

Restoration costs High restoration cost Reduce clean-up and restoration cost

Labor costs High labor cost for excavation and backfilling Less costly, minimum labor force

Equipment Costs Includes excavator and truck Includes drilling rig and excavator

Rate of Production

(Duration)Low (takes more time) High (takes less time)

Case Study 1

Eastland Texas

Location Eastland, Texas

Date of Installation March 10, 2010

Contractor Darnell and Dickson Construction Inc.

HDD Subcontractor Collier Directional Drilling

Length of Installation 318 ft

Nominal Diameter of the Pipe 6 in.

Dimension Ratio (DR) 18

Depth from Ground to Center of the Pipe 4 ft

Crew Details

1 Superintendent,

3 Workers,

1 Backhoe Operator

1 HDD Machine Operator,

1 Front-end Loader Operator,

1 Truck Operator

Equipment

HDD Model: Ditch Witch JT

2720,

Backhoe

Slurry Truck, and

Front-end Loader,

Vacuum Excavator

Soil Condition Clay, Sandy Soil, Gravel

Lubricant used for Drilling Bentonite, Polymer and Bore Gel

Size of the Reamer 10.5 in.

Access Pit and Receiving Pit 6 ft long, 4 ft wide and 4 ft deep

Scope - Case Study 1

Actual project carried out using HDD method of

installation

Product pipe used – Segmented 6” PVC pipe with

Bulldog Restrained Joint

Cost compared:

Open Cut vs. HDD

Using PVC (Internally restrained)

Open Cut vs. HDD

Using HDPE (Fusible)

Trench Cross-Section for Eastland, Texas

Bottom Width = 18 in.

Top width = 24 in.

De

pth

= 4

8 in

.

6 in. Embedment

6 in. PVC

Water Pipe

Bedding

Foundation

Parameters Quantity Take-off

Length = 318 ft

Depth = 4 ft

Top Width = 2 ft

Bottom Width = 1.5 ft

Area= Depth x (Top Width + Bottom Width)/2

= 4 x (2 + 1.5)/2 = 7.0 ft2

Volume of Excavation= Area x Length

= 7.0 x 318 = 2,226 ft3

6 in. PVC Pipe Installation by HDD

Method at Eastland, TexasAssembled Pipe Exit Pit Backfill Pipe Pull Back

Lined Pipe for Pull Back Entry Pit Pipe with Restrained Joints Section 2 Pull Back

(RS Means Cost Data, 2010)

(Contractor’s Bid)

Cost Breakdown Eastland, Texas

PVC PIPE

4,825

3,052

13,869

1,512

2,261

3,031

5,139

3,709

2,346

6,300

8711,454 1,632

2,936

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

Open-cut HDD

Exit Pit

Entry

Pit

HDD Rig

Water Tank

Vacuum

Excavator

Proposed 4” PVC Water

Pipe

16 “ Corrugated Steel

Storm Sewer Pipe

Existing 2” Galvanized

Steel Water Pipe

Location Clay County, Florida

Date of Installation 02-24-2010

Owner Clay County Utility Authority

Contractor Bore Hawg, Inc, Contact: Jason Riggs, President

Project Contact Steve Rencarge, Operations Coordinator,

Length of Pipe Installation 540 ft

Nominal Diameter of the Pipe 4 in.

Dimension Ratio (DR) 18

Depth from Ground to the Center of the Pipe 5 ft.

Crew Details

1 Superintendent,

3 Workers,

1 Backhoe Operator

1 HDD Machine Operator

Truck Operator

Equipment

HDD Model: Ditch Witch JT

1720 BackhoeVacuum Excavator

Slurry Truck

Scope - Case Study 2

Actual project carried out using HDD method of

installation

Product pipe used – Segmented 4” PVC pipe with

Bulldog Restrained Joint

Cost compared:

Open Cut vs. HDD

Using PVC (Internally restrained)

Open Cut vs. HDD

Using HDPE (Fusible)

Trench Cross-Section for Clay County,

FloridaTop width = 24 in.

Dep

th =

60

in.

Bottom Width = 18 in.

4 in.

Embedment

4 in. PVC

Water Pipe

Bedding

Foundation

Parameters Quantity Take-off

Length = 540 ft

Depth = 5 ft

Top Width = 2 ft

Bottom Width = 1.5 ft

Area= Depth x (Top Width + Bottom Width)/2

= 5 x (2 + 1.5)/2 = 8.75 ft2

Volume of Excavation= Area x Length

= 8.75 x 540 = 4,725 ft3

4 in. PVC Pipe Installation by HDD

Method at Clay County, FloridaBell & Spigot Joint Vacuum Excavator Pipe Joint HDD Reamer

Pulling Head PVC Pipe Lubrication of Joint HDD Rig

(RS Means Cost Data, 2010)

(Contractor’s Bid)

Cost Breakdown Clay County, Florida

PVC PIPE

8,390

5,307

18,161

2,510

3,5764,359

7,615

4,588

2,902

7,912

1,649 1,871 2,122

3,788

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

18,000

20,000

Open-cut HDD

Location: Eastland, Texas

Open-cut HDD

Pipe Material PVC HDPE PVC HDPE

Total Cost, $ 33,690.63 41,867.39 19,250 24269.20

Unit Cost, $/ft 105.95 131.66 63.12 79.57

Location: Clay County, Florida

Open-cut HDD

Pipe Material PVC HDPE PVC HDPE

Total Cost, $ 49,917.60 62,080.93 24,833.47 32,531.22

Unit Cost, $/ft 92.40 114.96 45.99 60.24

Eastland Eastland Clay County Clay County

Open Cut 105.95 131.66 92.40 114.96

HDD 65.27 80.16 45.99 57.10

$105.95/ft

$131.66/ft

$92.40/ft

$114.96/ft

$63.12/ft

$79.57/ft

$45.99/ft

$60.24/ft

0.00

20.00

40.00

60.00

80.00

100.00

120.00

140.00

160.00

Un

it C

ost

$/L

Ft

PVC

PVC

PVC

HDPE

HDPE

HDPE

HDPE

PVC

• Open-cut is more expensive than HDD installation for

Eastland and Clay County Project:

• Eastland, Texas

– Open-cut is 41% expensive than HDD

• Clay County, Florida

– Open-cut is 50% expensive than HDD

• Average segmented PVC is 19% less expensive than

fused HDPE pipe for HDD installation.

References

• Harbuck, R. (2000). “Economic Evaluation of Trenchless Technology.” Proceeding of

AACE International Transactions.

• Hashemi, B., Najafi, M., and Mohamed, R., (2008). “Cost of Underground

Infrastructure Renewal: A Comparison of Open-Cut and Trenchless Methods.”

Proceedings of ASCE International Pipeline 2008 Conference, Atlanta, GA.

• Haword, A. (2002). “Pipeline Installation: A Manual of Construction of Buried Pipe,”

Relativity Publishing, Leakwood, CO.

• Najafi, M., & Gokhale, S. (2005). “Trenchless Technology: Pipeline and Utility

Design,

• Construction and Renewal.” McGraw-Hill, NY.

• RS Means Database. (2010). “Building Construction Cost Data.” Construction

Publishers &

• Consultants, Kingston, MA.

• Willoughby, D.A. (2005). “Horizontal Directional Drilling (HDD): Utility and Pipeline

Applications” McGraw-Hill, NY.

Thank you