Inspire : Public Works Mar Apr 2013
52 Public Works Professional March-April 2013 STORMWATER PIPE RELINING ASHLEY BISHOP, ASSET MANAGEMENT OFFICER, BENALLA RURAL CITY COUNCIL, ASKS: Has anyone had recent experience in relining stor mwater pipe networks? I am looking for infor mation on linear cost, effectiveness, diffculty, why it was done and would you do it again? ROBERT BARBUTO, STORMWATER & DEVELOPMENT MANAGER, WARRINGAH COUNCIL, SAYS: Stormwater pipe lining is all we have been doing lately, using various contractors on all types of jobs. We have had good results as far as the installation is concerned, but only time will tell as far as job longevity. FRANK CHEN, STORMWATER ASSETS OFFICER, HOBART CITY COUNCIL, SAYS: Relining is really a good idea to deal with the stormwater pipes that are in complex circumstances, such as under buildings. We did some trials on relining small-diameter pipes and the results were good. However, the cost is close to our average cost using conventional replacements. We are also seeking a solution to repair large-size pipes that are not in good circular shape. Actually, there is an interesting question that has emerged after relining jobs: How do you assign a proper standard life to the pipes which have been relined? In addition, does anybody think a relined pipe is a renewed asset or an existing asset? Which way of counting the remaining life is better; adding certain years on to its remaining life or resetting its create date associating with a much shorter standard life? DAVID GRASBY, ASSET MANAGER, STORMWATER, SYDNEY WATER, SAYS: In ter ms of merging the old asset record with the new expected lifespan, we generally apply an 'improvement' to the original asset and extend the life by 70 years from the relining date. We add relining particulars to the asset record in both our GIS and asset register. Our sewer assets were revalued a few years ago to separate the value of pipe (excavating and relaying a replacement asset) and value of the void (using the existing value tied up in not having to re- excavate in the case of relining). In such a disaggregation, the pipes have longer lives than the voids, which are relined and a new void asset is created. This makes for complicated accounting, but I understand it makes for clearer accounting on the asset register once it is deployed. KNOWLEDGE CENTRE ASK YOUR MATES THE HOT TOPICS OF DISCUSSION ON THE IPWEA ONLINE FORUMS. JOIN THE DISCUSSION NOW AT www.ipwea.org.au/askyourmates ALSO UP FOR DISCUSSION • Public swimming pool management contracts • Engineering decisions by unqualifed engineers • ‘Lef-side-only’ access for purpose-built trucks • Asset handover framework and guidelines # MOORING STANDARDS MICHAEL READ, DESIGN ENGINEER, COWRA SHIRE COUNCIL, SAYS: When watching the food coverage on TV, I noticed a lot of jetties foating away, moorings breaking and boats foating down rivers. My thought was: Why weren't the design standards for these structures able to handle the food velocities? Maybe those responsible for the standards need to address this issue. GLEN POPOWSKI, ENGINEER, CLARENCE CITY COUNCIL, SAYS: AS3962 Design of Marinas deals with the issue of environmental loading but relies on the designer being able to determine or access the data on food velocities at the appropriate location.
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