The repair job – located in Hoddle Street, East Melbourne – comprised the removal of a troublesome JUG I/S connection, where a retic sewer connects directly into another retic sewer at a higher level and without a manhole.
The existing JUG was cast iron and heavily calcified, which reduced the diameter and resulted in a high risk of sewer surcharge. The solution was to eliminate the JUG connection by installing a new sewer manhole completely.
Safety first
To install the manhole, the excavation needed to be 6.3 m deep and located in the middle of the two northbound centre lands of Hoddle Street.
To safely excavate the shaft, Vic Roads was engaged to close three of the four Hoddle Street lanes. Rangedale says transitioning approximately 3000 vehicles during peak hours through the single accessible lane was a major traffic control undertaking, although it was vital to keeping the site safe.
During the excavation, Rangedale encountered rock that required breaking out, which slowed down the project and had an impact on the program. Once the excavation was complete, the manhole base was poured and completely formed by the following day.
The sewer was kept live and running throughout the entire process, with Rangedale redirecting the sewer into the new manhole via an internal drop pipe, after which the backfill and asphalt restoration was completed to the Vic Roads standards.
The team worked on the job 24 hours a day and completed the restoration in less than a week.
In-house resources
As the Rangedale Group of Companies is vertically integrated, completion of the entire project was possible using in-house resources at short notice.
These resources included Asset Survey Solutions, Rangedale Saw Cutting Services, Rangedale Drainage for hydro excavation, Rangedale Civil to carry out the excavation and manhole building, Rangedale Asphalt Services to complete the final road restoration and RTM Traffic Solutions for traffic management plans and the execution of all traffic control.
Rangedale says the emergency repair was a huge success and credits the positive outcome to a great effort by all involved.
This article was featured in the June 2020 edition of Trenchless Australasia. To view the magazine on your PC, Mac, tablet or mobile device, click here.
For more information visit the Rangedale website.
If you have news you would like featured in Trenchless Australasia contact Journalist Sophie Venz at svenz@gs-press.com.au