Franklin Street Bus Depot 2007

Excavation of 300 m2 site to depth of 450mm for installation of trees in paving over SPACE in Northern Section of Bus Depot

Trench 50m x 6m x 450mm ready to accept SPACE Structural Soil

SPACE Shuttle delivers first of 120m3 to northern promenade

SPACE spread in 200-300 mm lifts in trench

 

 

Each layer of SPACE compacted

Inline drippers installed at each location

Each tree location marked with Greenwell

 

 

Paving base installed

150 layer of X6 paving base over top of SPACE

Tree location preserved with Greenwell

 

 

 

Root barrier installed to protect heritage building

Root barrier to 1200 mm

 

 

 

 

 

Corymbia maculata grown in 400mm ;Rocket pots installed in northern section

Corymbia maculata installed in southern section

Trees approximately 2400 high with 40 mm caliper

Installation in Southern section showing irrigation over SPACE trench

5 years later

5 years later

In 2007 a new Adelaide Interstate bus depot was built on the site of the old one in Franklin Street in the CBD.

As the site was heavily contaminated with material such as oil, diesel fuel, and heavy metals, a deep excavation was made in the north-west corner of the site and the contaminated soil was buried under a one metre cap of compacted clay.

This was unfortunate because the only landscaping permitted in the pick up and drop off area was the installation of small shrubs in raised boxes to avoid the breaching of the clay cap by tree roots. Given that any trees planted would struggle in such compacted clay in any case, Adelaide City Council set the architects Wood Baggot the task of finding solutions to the ban on trees. Without the shade and visual amenity provided by healthy tall trees the extensive paved area would have been a very hot and unwelcoming environment for travellers.

The solution was to place the paving on a 450mm deep layer of SPACE and pave directly over that. The SPACE was easily installed and compacted in 200 -300 mm lifts. The location of 29 advanced spotted gums (Corymbia maculata) was marked with Greenwells and sub irrigation lines installed to water each tree.

The trees quickly became established and are continuing to thrive without presenting any threat to the integrity of the pavement or roadway. The l use of SPACE by the Adelaide City Council was successfully employed in other similar projects in the CBD along North Terrace , the City West Campus of Uni SA, The Festival Centre, Hindmarsh Square and various commercial housing developments.