D AA R Michael P. Doble, P.E., [email protected], 414-935-4435, PROPRIETARY AND CONFIDENTIAL. © 2013 DAAR ENGINEERING, INC. ALL

D A ARMichael P. Doble, P.E., [email protected], 414-935-4435, www.daarcorp.comPROPRIETARY AND CONFIDENTIAL. © 2013 DAAR ENGINEERING, INC. ALL RIGHTS RESERVED.

ADVANCED METHODS FOR SURVEYING BURIED UTILTIES

INTRODUCTION TO SPAR AND CASE STUDYTHE INFORMATION CONTAINED HEREIN IS PROPRIETARY AND CONFIDENTIAL.

© 2013 DAAR ENGINEERING, INC. ALL RIGHTS RESERVED.

LEADERSHIP

EXPERIENCE

QUALITY

D A A R

KNOWLEDGE


Summary• Problem/Solution• The Spar 300 System• Why a 3d Survey?• 3d Survey Concepts• Sample Projects

– High Pressure Gas Main Relocate– DOT Highway Project– Cable Crossing in River


The Problem

• Poorly mapped and abundant existing underground facilities complicate design and excavation

• Current Workflow– One-call service: Facilities marked– Facilities are un-earthed for depth– Spot location depths documented

• Problems– 2d data inaccuracies due to distortion– Spot depths may or may not tell the whole story– Depths are documented; not elevations

• Results– Designs require utility relocation– Utility strikes are common and

dangerous – April 2nd, 2008


The Problem


The Solution

• Prepare a 3d survey!• The Spar System

– 3d Magnetic Sensor– Trimble Access:

• Utility Survey Software• FieldSensTM Technology

– Trimble RTK-GNSS receiver– Transmitter


Why is Surveying Better than Locating?• We are professional surveyors: we provide professional quality data

• Avoid strikes and improve safety with accurate surveying• Provide for improved design workflow: data up front• Measure and document locating subsystem RMS error • Reduce depth ambiguity by surveying elevations (x, y AND z)• Locate with survey grade precision: RTK-GNSS• Combine overall errors from geospatial and locate subsystems

– Reduce the total effort to locate, map, document

• This technology allows for surveying from offset positions– Map the line without constant need to stay on peak or CL– Move away from distortion– Termed as casual contact– Survey where traditional methods don’t allow


Underwater or Deep Utility Mapping

Wireless sensor networking, synchronization results in improved measurement geometry


0 1 2 3 4 5 6 70

0.005

0.01

0.015

0.02

0.025

0.03

meters

field

str

engt

h, m

A/m

PeakNull

Single-Spar Line Mode

Target cable“Bleedover” cable

Model


Spar Range Summary

•Single Spar Line– Single epoch measurement, <3 meter range

•Dual Spar Line– Single epoch measurement, <15 meter range

•Dual Spar Sonde Tracking– Single epoch measurement, <8-12 meter range


Representative Projects

• High Pressure Gas Main Relocate– Objective: Save cost on hydroexcavation– Objective: Verify a difficult locate

• DOT Highway Project:– Objective: Save time and avoid utility strikes

• Cable Crossing in River– Objective: Document cable location for dredging


High Pressure Gas Relocate


Hydroexcavation to Verify


Depth Verification


Wisconsin Hwy 33 Saukville


Cable Crossing in River


Dual-Spar Water Locate Set-up


Project Results

• High Pressure Gas Main: Gas utility crews saved three days of excavation time in verification of pipe location and elevation

• Highway Project: Grading crews were able to grade over the line without any inadvertent strikes

• River Crossing: Dredging crew was able to dredge with confidence allowing the work to be completed in this section two days ahead of schedule


DAAR Experience in Summary

• Spar performed as specified• Gas main and tap elevations consistently measured from

surface to 12 feet below ground with accuracy of +/- 3 to 5 inches

• Highway 33 project compared previously measured gas main GPS elevation points to Spar data and noted +/- 1.5 inch elevation differences – very good!

• DEEP depths provide a challenge• Liability concerns alleviated by documented accuracy


QUESTIONS

INTRODUCTION TO SPAR AND CASE STUDYTHE INFORMATION CONTAINED HEREIN IS PROPRIETARY AND CONFIDENTIAL.

© 2012 DAAR ENGINEERING, INC. ALL RIGHTS RESERVED.D A A R

ADVANCED METHODS FOR SURVEYING BURIED UTILTIES


System Architecture


Note Records in Trimble Access


Export of Data


CSV File: Translated


EMF Equipment


EMF Connections

Documents

D AA R Michael P. Doble, P.E., [email protected], 414-935-4435, PROPRIETARY AND CONFIDENTIAL. © 2013 DAAR ENGINEERING, INC. ALL