Evaluate Inspection Technologies for Hydraulic Structure Inspection
Draft Implementation Plan
Prepared by: EVS
Notes:
Blue infrastructure means any of the infrastructure in the roadway system designed to
convey and treat stormwater. Examples include gutters, inlets, storm sewer, culverts,
ditches, and stormwater BMPs such as wet detention basins, ditch check dams, etc.
I.
Project Background -- Evaluate the results of the completed research
There is a strong consensus among Mn/DOT maintenance and hydraulic engineers that
blue (hydraulic) infrastructure maintenance is a top area of concern.
From Dave Solsrud’s “Research Problem Statement I09PS01”:
“Maintenance of Mn/DOT's highway drainage infrastructure is perceived to be suffering
from the re-prioritization of resources. Inventories show that many structures are failing
due to corrosion, separation, siltation, and erosion. Due to the relatively low profile of
status of drainage infrastructure, maintenance actions necessary to rectify these
problems are typically deferred until complete failures (typically threatening or actually
undermining of the driving surface) take place. At that time emergency actions are
taken.”
Maintenance of hydraulic structures is done on a corrective (crisis) basis and not a
preventative basis. Mn/DOT maintenance staff is overloaded with hydraulic structures
that are in poor condition and need repair. Several ideas have been proposed to help
Mn/DOT maintenance staff with this challenge. The idea of utilizing the latest
“inspection technologies” for hydraulic structure inspection has the strongest consensus
among Mn/DOT maintenance and hydraulics engineers.
Research Problem Statements include:


II.
I09PS01 (Research Problem Statement) Impacts of limited maintenance of
highway drainage infrastructure
2000-04 Best Practices Handbook on Asphalt Pavement Maintenance – use for
information on advantages of a preventative maintenance approach.
Project Description
a. What is the purpose of the proposed project?
Note: Also see information in appendices.
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The purpose of this work is to determine if new inspection technologies can
provide a useful “follow-up” hydraulic structure inspection. The existing
hydraulic structure is visual. The new inspection technology would provide the
ability to determine more details on structures showing distress. For example,
they would show voids in the soil envelope around the pipe. This would be very
useful in helping Mn/DOT maintenance and hydraulic engineers determine
maintenance actions needed. It would help plan preventative maintenance before
structures fail which then require much more costly “crisis“ repair.
b. What is the proposed project?
These three technologies will be evaluated for effectiveness:
1. Ground Penetrating Radar (GPR)
2. Infrared Thermography
3. Ultrasound Inspection (Sonar)
This project will consist of an evaluation of the effectiveness of “inspection
technologies” listed above. The deliverable of this project will be:




Evaluation of each technology relative to effectiveness for hydraulic
infrastructure maintenance.
Recommendations as to which technologies would provide valuable
information for hydraulic structure inspections.
A discussion of the logistics in obtaining and utilizing the equipment
required for the inspection technology.
A discussion and recommendation for the next project phase (Phase 2): i.e.
purchasing, piloting, and utilizing the technology.
This is “Phase 1” of a two phase project. The second phase will include piloting
and then making the inspection services available statewide. There is a task below
that includes the recommendations for proceeding with Phase 2.
c. Are the results “implementable”?
This project will recommended technologies that can be utilized statewide.
d. Can implementation of the results yield benefits?
Meeting the goals of this project will result in cost savings in both time and
materials in fixing problems before they become urgent. In some cases, we're
preventing the need to replace structures and repair adjacent roaday, which is a
huge cost savings.
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e. Who will implement the proposed solution?
The proposed solution will be implemented by:

Mn/DOT Researcher – will be responsible for evaluating new
technologies, working with Mn/DOT operations & maintenance engineer,
and preparing evaluation reports. The research will be done by a Mn/DOT
research project engineer at the Mn/DOT Office of Materials and Road
Research. To help identify the researcher, contact Matthew Lebens P.E.,
Research Project Engineer, Mn/DOT, Office of Materials and Road
Research.
Mn/DOT Operations & Maintenance Engineer -- will work with
researcher and help provide direction and expertise from the engineering
(experience) side. To help identify the operations & maintenance engineer,
contact Dave Solsrud, Operations Engineer, Willmar; or James Michael,
Transportation Operations Supervisor, Water’s Edge.
Equipment vendor representative(s) (see task 3 below


III.
Project Tasks
Costs for the tasks below are broken into “External Costs” (outside Mn/DOT) and
“Mn/DOT Staff Hours” (within Mn/DOT).
Task 1: Identify technologies that warrant testing
Duration:
Responsibility:
Approximate External Cost:
Approximate Mn/DOT Staff Time:
8 weeks
Research Engineer
$0
100 hours
For each candidate inspection technology listed in Section II.b, do the following:
1.
2.
3.
4.
Conduct literature searches on technologies
Contact other DOT’s or agencies who have used the technology, if any.
Request demo’s of technologies from vendors
Determine if the technology shows potential and if testing is warranted
Task 2: Prepare testing plan
Duration:
Responsibility:
Approximate External Cost:
Approximate Mn/DOT Staff Time:
2 weeks
Research Engineer, Maintenance Engineer
$0
40 hours
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The inspections will be run at Mn/ROAD where there are several large culverts of
different types (concrete, steel, plastic) in place. This testing location will provide a
safe (w/o traffic) testing environment without interruption of traffic. All technologies
could be tested at the same time for real-time side by side comparison.
This work includes:
1. Mn/DOT Operations and Maintenance Engineer should identify a minimum
of ten different test cases with variables including (structure material, size,
conditions -- voids around the pipe).
2. Identify equipment vendors who will rent equipment for testing
Task 3: Acquire equipment for testing
To minimize equipment rental costs this task will be relatively intense.
Duration:
Responsibility:
Approximate External Cost:
Approximate Mn/DOT Staff Time:
4 weeks
Research Engineer, Vendor Representative
$12,000
30 hours
A formal Partnership Agreements will be reached with vendors for conducting demos
to test proof of concept, acquisition/rental of equipment for the various technologies
to be tested and vendor assistance in analyzing the test results.
Assume $2,000.
Rent equipment at $1,000 per week (see Appendix 3). Assumptions:
 Assume that two technologies warrant testing
 Each technology requires rental of two instruments (different models)
 The testing period will be four weeks, with two instruments showing the least
effectiveness eliminated and returned to the vendor after one week (to
minimize rental costs)
(first week)
Rental cost = 4 instruments * $1,000 / week = $4,000/week * 1 week = $4,000
(weeks two through four)
Rental cost = 2 instruments * $1,000 / week = $2,000/week * 3 weeks = $6,000
Task 4: Conduct tests to determine effectiveness
Duration:
4 weeks
Responsibility:
Research Engineer (80%), Maintenance Engineer (20%)
Approximate External Cost:
$0
Approximate Mn/DOT Staff Time:
160 hours
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For each inspection technology identified to warrant Mn/DOT testing for
effectiveness as hydraulic structure testing tool, perform tests to determine
effectiveness of technology for inspection of hydraulic structures.
To be “effective”, the technology must be relatively easy to use and must be able to
identify voids in the soil envelope around the pipe.
Task 5: Provide recommendations for effectiveness
Duration:
Responsibility:
Approximate External Cost:
Approximate Mn/DOT Staff Time:
1 week
Research Engineer, Maintenance Engineer
$0
24 hours
Provide purchase recommendations (including costs) as to which, if any, of the
inspection technologies should be purchased by Mn/DOT based on the results of the
tests conducted in the previous step.
Task 6: Develop draft guidance for inspection results
Duration:
4 weeks
Responsibility:
Research Engineer (10%), Maintenance Engineer (80%), HYDINFRA
Coordinator (10%)
Approximate External Cost:
$0
Approximate Mn/DOT Staff Time:
80 hours
Develop draft guidance that suggests specific maintenance as a function of the
inspection technology results. This should be integrated with “Repair Flowchart”
developed by Bonnie Peterson and Dave Solsrud.
Note that this guidance will be refined and finalized during Phase 2.
Task 7: Recommend next actions (Phase 2)
Duration:
Responsibility:
Approximate External Cost:
Approximate Mn/DOT Staff Time:
2 weeks
Research Engineer
$0
30 hours
If any of the technologies were determined to be effective, recommend the next
actions. For example, purchasing, piloting, and utilizing the technology.
Note that the next phase should also include the HYDINFRA Coordinator to
determine how existing inspections should “request” follow-up inspections using the
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new technology. Determine if new flag is needed in HYDINFRA or if existing field
will work (i.e. “comment” field) to indicate that a follow-up inspection has been
requested using inspection technology (contact: Bonnie Peterson, HYDINFRA
Coordinator).
Note: For next phase, the Material Office currently has a GPR request form (word
doc) that has been distributed to the District Materials Engineers at their annual
meeting. This request is used for GPR pavement inspections. Hydraulic structure
inspections would be done similarly.
IV.
Project Schedule
Project Schedule
Identify technologies that w arrant testing
Prepare testing plan
Acquire equipment for testing
Conduct tests to determine effectiveness
Provide recommendations for effectiveness
Develop draft guidance for inspection results
Recommend next actions (Phase 2)
0
5
10
15
20
25
Weeks
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V.
Preliminary Estimate of Costs
Summary of Project Costs
Task
Description
Duration
(weeks)
1
2
3
4
5
6
7
Identify technologies that warrant testing
Prepare testing plan
Acquire equipment for testing
Conduct tests to determine effectiveness
Provide recommendations for effectiveness
Develop draft guidance for inspection results
Recommend next actions (Phase 2)
8
2
4
4
1
4
2
Approximate
External Cost
Approximate
Mn/DOT Staff
Time (hours)1
$0.00
100
$0.00
40
$12,000.00
30
$0.00
160
$0.00
24
$0.00
80
$0.00
30
Total
$12,000.00
Notes:
1) Mn/DOT staff time includes Research Engineer and Operations & Maintenance Engineer
VI.
Performance Measures
The proposed use of new inspection technologies for hydraulic structure inspection will
produce measurable outcomes. This plan is for Phase 1 of a two phase project. Phase 2
will include piloting and a plan for making the new technologies available statewide.
These performance measures computed after Phase 2 is complete.
Performance measures will be done as follows:




After the inspection technologies have been used for maintenance inspections for
one year, determine how many structures were identified using the technologies to
have voids in the soil envelope around the pipe
Compute the preventative maintenance costs performed as a result of these
inspections
Estimate the “crisis” maintenance costs that would have been required if the voids
would not have been identified. There are many examples of “crisis” hydraulic
structure maintenance projects that can be referenced statewide.
Compare the preventative maintenance costs versus the estimated “crisis”
maintenance costs
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464
Appendices
Appendix 1 – Research and Mn/DOT Experts





Research Problem Statement I09PS01
Andrea Hendrickson, State Hydraulics Engineer
Jeremy Hadrava, Senior Engineer, Bemidji Hydraulic
Jon Bergstrand, Transp Specialist, Duluth District
James Michael, Transportation Operations Supervisor, Metro District
Appendix 2– Notes



Ultrasonic inspections may be limited to concrete, clay and plastic pipes (needs to
be verified)
See Road-Map correspondence 6/11/08, Matthew Lebens, Materials Office, for
known limitations of above-ground GPR for structure inspection.
A couple starting points for research literature review may be:
o Management and maintenance practices of storm and sanitary sewers in
Canadian Municipalities, E. N. Allouche, Ph.D., P.Eng., P. Freure,
B.E.Sc., The University of Western Ontario, Geotechnical Research
Centre, Department of Civil and Environmental Engineering, April 2002,
ICLR Research, Paper Series – No. 18
o ISTT – ASTT Surveys and Site Investigateions, Australian Society for
Trenchless Technology (ASTT)
Appendix 3 – Equipment
Correspondance
----- Original Message ----From: "Matthew Lebens" <Matthew.Lebens@dot.state.mn.us>
To: <garypeterson4@qwest.net>
Cc: <pkeranen@evs-eng.com>
Sent: Wednesday, June 11, 2008 12:13 PM
Subject: Re: Ground Penetrating Radar Use
From Matthew Lebens P.E., Research Project Engineer, Mn/DOT, Office of Materials
and Road Research
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I'll request info from the GPR equipment manufacturer specifically about Culvert and
Pipe surveys - it might be that there is equipment available to survey them from the inside
(or something) that Mn/DOT doesn't have. If there is other equipment available, it could
be acquired and tested as part of such a research project.
6/26/2008
Phone conversation
Gary Peterson, EVS with “Imaging Products Group / Newco” sales representative
Trying to get high-level idea of product pricing and if demo/rent/etc is available.
Their primary focus is on inside-the-pipe issues, but said their instrument may work to
identify outside-the-pipe voids with use of hand-help probe and 200 foot cable. Prices
range from $2,000 to $6,000. Rental is approximately $750/week. They also allow
returns of purchased product if still like new. Minnesota is outside their normal demo
area, so we would want to try to find a closer vendor for initial demo.
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