Pipe Users Group May 21, 2013 - norcalpug.com

Stockton Delta Water SupplyConstruction Challenges and Resolutions

Bruce J. Corwin, P.E.Vice President

Pipe Users Group

May 21, 2013

Outline

• Introduction• Project Description• Raw Water Pipeline Challenges and Resolutions• Treated Water Pipeline Challenges and Resolutions

• General Challenges and Resolutions• Summary

Where is Stockton?

Introduction

• Over $200 million Progressive Design Build Project including a 30 mgd WTP

• Pipeline portions of Project completed August 2011 and began design in 2007

• Over 12 miles of 54 inch raw water pipeline• Over 7 miles of 36‐54 treated water pipeline• Two roadway crossings, two I‐5 crossings, two railroad crossings, crossing of Pixley Slough and two major canal crossings (9 microtunnels)

Progressive Design Build

• Allows interaction in design up to 65%• Competitive bids received on packages

– CDM Smith General Contractor/Designer• Sundt won Pipelines• Vadnais won Tunnels

• Construction starts while design moves to completion

• Successful process allowing an integrated approach with Owner input throughout

Project Description

• Raw water intake by others DBB• 30 mgd water treatment plant expandable to 60 mgd

• 54 inch raw water line with provisions for future 72 inch additional pipe

• Project provides supplemental water supply for Stockton

• 36 to 54 inch treated water lines connect to City system

Project Description

The Pipeline Setting

• Routed through or near farmland and along a rural highway and City streets past commercial development

• The handling of groundwater• Trench design features vary along the alignment• Public issues include business and residential access• The 54‐inch raw water line designed to allow for an adjacent future 72‐inch raw water line, which will have cross connections between the two pipes.

Pipeline Hydraulics and Diameters

• Design flow 60 mgd at maximum capacity– Raw water 54‐inch

– Surge control by 32 air valves and surge tank at Intake (Per intake designer)

– Treated water 54‐inch until it branches, then 42‐inch to 36‐inch

• City H2ONET model used to finalize diameters• Working pressure 70 psi

– Surge control by surge tank at WTP TW pump station

Geotechnical Study

• West of Honker Cut– Peat/organic, clay, and silt underlain by sandy soils with high

groundwater• Pipe lowered to get below peat and organics

• King Island to I‐5– Clay, sand and silt with high groundwater on King Island and low

groundwater toward I‐5• Remainder East of I‐5

– Sand, silt and clay no groundwater

Pipe Materials Bid as Well

• Depth of Cover– Mostly 4 feet, but can go up to 30 feet

• Pipeline Design Recommendation– Welded steel AWWA C‐200 vs.– Bar wrapped cylinder pipe AWWA C‐303

• Tunnel Design Recommendation– Permalock casing pipe and C‐200 or C‐303 inside at UPRR

crossings– All other tunnels use direct jack RCCP C‐300

Corrosion Study

• Soils are highly corrosive–Bond all non‐welded pipe joints– Install active cathodic protection system– Install test stations at 800 to 1,000 foot intervals

– Isolate pipe from other structures

Traffic Concerns and Issues

• West of I‐5– Mostly a concern to Trinity Parkway and then just minor effects on Eight Mile Rd. except for truck traffic

• Davis Road– Minimum of one lane open, K‐Rail may be required and work may be restricted from 9 am to 3 pm

“Parallel Teams” Construction Strategy Mitigates Construction Window Limitations

East of I-5West of I-5

Construction Schedule

• Procure Pipeline and Tunnel Contractors by 2/10/2009

• Begin construction by 3/3/2009– Work in allowable permit periods

• Swainson Hawk East of I‐5–Sept. 1 through Feb. 15

• Giant Garter Snake West of I‐5–May 1 through Oct. 1

– Assumed production rate of 400 feet per day

Eight Mile Road Crossing

• Minimizes pipe settlement

• Eliminates siphon and blowoff

West 8 Mile RoadWest 8 Mile Road

Honker C

utH

onker Cut

Bishop C

utB

ishop Cut

Atherton R

oadA

therton Road

Correla R

oadC

orrela Road

Rio Blanco R

oadR

io Blanco Road

Intake LocationIntake Location

KingIslandKingIsland

West of I-5West of I-5

• Deeper is better• Microtunneling in ground water

EmpireTractEmpireTract

Tunneling Approach

• Remotely controlled with no personnel entry • Tight Tolerance for Line and Grade (1”)• Use the same machine for all crossings

Microtunneling Approach

Minimum Construction Corridor Width

Go with 4 feet wall to wallseparation and use acommon trench

15 ft. common trench

Raw Water Pipeline Challenges and Resolutions

• Connection to Intake– Moved closer to avoid digging in new levee

• Construction near existing levee– 200 feet from CL of levee

• Construct in peat soils

• Determined CDF better than burrito


Proposed trench in peat areas

• CDF installation quicker and more cost effective than Burrito

• 100 psi CDF


• Ground water was challenging– Well points used– No surface discharge

– Land disposal worked


• Honker Cut Canal Crossing


• Bishop Cut Canal Crossing


• I‐5 Crossing originally microtunnel


Interstate 5 VE Recommendation

• VE Result open cut night time construction


• Treated water movement


• Reroute to avoid trafficissues

Treated Water Pipeline Challenges and Resolutions

• Move closer to raw water

• Use CDF and place 2 feeta part


Utilities Increase ROW Required

• Existing PG&E Gas and Buried Telephone need 20’ Additional Permanent and 30’ of Additional Temporary ROW (Total 50’)

E. Eight Mile RoadE. Eight Mile Road

Thor

nton

Rd.

Thor

nton

Rd.

Legend _Legend _Raw WaterGasTelephone

Raw WaterGasTelephone

Added ROW 50’Added ROW 50’

Existing 80’ ROWExisting 80’ ROWUltimate ROW 134’Ultimate ROW 134’

• Trouble with PG&E As‐Builts and Markings


• Railroad Crossings – Required casing so jacked Permalock and then installed C‐303 inside


Eight Mile Road / UPRR Grade SeparationC

ontinued

Eight Mile Road / UPRR Grade Separation

Continued

• Connections to City water system


• Bedding operations worked well

General Pipeline Challenges and Resolutions

• Nine microtunnels were used – Jacked C‐300 except RR where Permalock was jacked


• Pipeline stringing along ROW worked great


Summary

• Pipelines installed on schedule with min. Change Orders• Overall construction successful with no accidents• Delivered under original budget• Now under one year operational warranty

Recently won Sacramento Section of ASCE Water Quality Project of the Year Award, ENR Merit Award and ACEC Merit Award

QUESTIONS

Bruce J. Corwin, P.E.Vice President

[email protected]

Documents

Pipe Users Group May 21, 2013 - norcalpug.com