Subsurface Utility Engineering
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Purdue University Study
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Prof. J.J Lew, P.E.
James H. Anspach, P.G.
C. Paul Scott, P.E.
Kevin Slack, P.E.
The Federal Highway Administration (FHWA) commissioned Purdue University to study the effectiveness of subsurface utility engineering (SUE) as a means of reducing costs and delays on highway projects.
Previous studies and statements of cost savings were performed by various state DOTs, providers of SUE services, and the FHWA.
Commissioning Purdue University to conduct this study allowed for an independent and impartial review and study of costs savings.
Four States were selected to participate
North Carolina DOT
General Investigative Procedure
General Investigative Problems
Developed checklist of 21 areas for potential project savings
Slide 11 - 12
Areas for Savings
Many of these areas could not be quantified in the study
The reductions in risk for projects utilizing SUE have been difficult to quantify. There are many variables and scenarios that may occur. Historical data is difficult to come by. Some savings are easily quantified; others may be qualitative or speculative in nature.
This study categorizes savings accordingly. These types of costs are:
Exact costs that can be quantified in a precise manner.
Examples are costs much like the costs for test holes, the cost to eliminate construction and utility conflicts, or any other cost for which exact figures can be obtained.
Estimated costs that are difficult to quantify, but can be calculated with a high degree of certainty.
These costs were estimated by studying projects in detail, interviewing the personnel involved in the project, and applying historical cost data.
Costs that cannot be estimated with any degree of certainty due to a lack of data.
These are true qualitative costs and may in fact be significant to the real cost savings. These qualitative costs are not quantified in the evaluation study.
It is believed that the majority of savings fall into this category
Therefore, the cost savings reflected from this study are a MINIMUM QUANTIFIABLE SAVINGS
True project savings are likely to be significantly higher than this study can prove.
Study Results - Virginia
Study Results - North Carolina
Study Results - Ohio
Study Results - Texas
From a study of 71 projects with a combined construction value in excess of $1 billion, the results indicated the effectiveness of the study was a total of $4.62 in savings for every $1.00 spent on SUE. The costs of obtaining QL B and QL A (except NCDOT) data on these 71 projects were 0.5 percent of the total construction costs, resulting in a construction savings of 1.9 percent by using SUE.
Qualitative savings were non-measurable, but it is clear that those savings are also significant and may be many times more valuable than the quantifiable savings.
Only three of 71 projects had a negative return on investment
One individual project had a $206.00 to $1.00 return on investment (NCDOT).
This leads to the conclusion that SUE should be used in a systemic manner, i.e. on virtually every project
Using the data from this study and given a national expenditure in 1998 of $51 billion for highway construction, the use of SUE in a systemic manner should result in a minimum national savings of approximately $1 billion per year.
QL B / QL A mapping budgets should be approximately 1% of state DOT Eng/Constr Budget
This study shows a potential minimum stretching of project dollars by 4.62% if comprehensive QL B / QL A mapping is performed correctly.
State DOTs and their consultants should integrate this SUE mapping with the pending ASCE / ANSI Standard
Standard Guidelines for the Collection and Depiction of Existing Subsurface Utility Data
Antic. Publish date - 2002
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