Objectives - uta. Introduction Open-cut Installation Horizontal Directional Drilling Installation Advantages of HDD vs. Open-cut Social Cost

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  • 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

    Contractors 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)

  • (Contractors 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)

  • (Contractors 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 1,8712,122

    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 Mean