Tonsley Subdivisions

DESCRIPTION OF PROJECT

Tonsley Development is in an old industrial area on the south western fringe of Adelaide. This is a large parcel of land situated next to the recently converted old Mitsubishi Factory. It is now an innovation hub with Flinders University and small
start-up businesses. This large area was full of uncontrolled fill and potentially contaminated material / groundwater which requiring in depth planning to work through.

As part of stage 1 a large amount of earthworks remediation was completed across 1/3 of the whole site. Excavators were used to remove the uncontrolled fill, moisture condition and then compact under level 1 supervision. Some bore holes were completed before the works started to determine the approximate quantity of uncontrolled fill that was across the site. The depth of the remediation varied between 1 m and 4 m across the site. Survey was used to pickup the natural material layer and the client was charged on this basis.

After the remediation was completed the sewer, stormwater and water services were constructed. The road construction followed and then CST works. This site has been unique in that the footpaths were not completed until after the buildings were built. This has proved challenging coming back to site to complete small portions of footpath with traffic and pedestrian management signage in place.

Up to now 2 stages of bulk earthworks remediation have been completed with an approximate quantity of 50,000 m3 of remediation cut to fill and also around 10,000 m3 of import to fill. Through the 4 stages completed at Tonsley some 130 allotments have been created with all associated services and road construction.

PROJECT CHALLENGES

The remediation was completed by excavating the uncontrolled fill and then re compacting. Fill from stockpile/ imported was then required to fill to the desired levels. The stockpiles on site had not been tested which may have provided significant delays. Because the Darlington Project was within close approximate to the Tonsley works T & J Constructions were able to source clean material from this works and continued filling of the site. T & J Constructions were able to accommodate these changes which provided significant cost savings for the client.

Whilst there was a wait for this material to come from Darlington as the projects did not perfectly coincide. To prevent any holdups the earthworks was completed on the sub division area first, so these works could continue whilst waiting for the Darlington material.

The site has some contamination and as a result the engineers specified for every trench entering the site to have a vapour stop. Experienced operators where required to delicately excavate around the laid services so the concrete trench stops could be completed. A detailed specification was followed through the construction.

The Tonsley development is a condensed development with small frontages. Typical frontages within are 4.4 meters. These lots had potable water, recycled water, gas, sewer, stormwater and NBN services going to each lot. Great care was taken in ensuring that the correct separation was maintained between all services into these small lots. This was a significant challenge throughout the project.

Tonsley Development has been set up with Enwave to provide the services to the subdivisions for electrical, recycled water and gas.

Minor changes have been completed to work for Enwave for the electrical and recycled water however there is some larger changes with the associated gas network. Instead of APA coming in and completing the gas works as per standard procedure T & J constructions were contracted to directly to complete the private gas network. T & J Constructions was able to adapt and complete these works with no impact on the program and have now completed four stages of gas network.

KEY CONSTRUCTION PROCESSES