University of Tasmania (UTas) Stadium Redevelopment

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UTas Stadium completed and presented for the NAB Cup AFL match, 2020

UTas Stadium was established in 1921 in the flood plain of the North Esk River in Launceston, Tasmania. It is a prominent landmark of North East Tasmania that attracts a wide range of elite sporting fixtures from Big Bash Cricket matches for both men and women, to Tasmanian Premier League and AFL matches.

Over time the UTas Stadium’s pitch surface had developed an array of issues:

  • An aging and uneven surface that holds water
  • Poor drainage performance
  • Excess thatch levels
  • A playing surface heavily infested with Poa annua

In 2017, the City of Launceston engaged STRI Australia to provide technical consultancy in the re-build of the stadium’s playing surface along with the associated infrastructure.

Stage 1
Identifying challenges
The reconstruction of the UTas Stadium pitch required extensive design and engineering work because of the site’s landfill history, its proximity to the North Esk River and the tidal water levels effecting ground water levels and the proposed earthworks.
It’s important to note this region of Tasmania is not naturally blessed with a sand that meets rootzone profile specifications, which meant sand would need to be sourced elsewhere.
The stadium pitch was designed for the demands of multi-sport use and entertainment events, for the present and the future. This included electric cabling for the LED signage and communication cabling for broadcasting and other entertainment events. All of these elements needed to be considered in the redevelopment.
Stage 2
Finding the solution
The new oval was designed to be realigned and repositioned to allow for a slight change in shape to a conventional oval shape. The proposed dimensions were 175m in length and 142m wide (approx. area of 19,515 m² (fence to fence). The oval was designed to form a domed surface from a pre-existing flat surface. The dome was created with a 250mm sand profile over an aggregate drainage layer on a clay base with a 0.5% grade from the central point to the boundary. A concrete v-spoon drain was to be installed around the perimeter, but also designed to accommodate the fencing infrastructure and a communication cable tray.
The construction program also included sub-grade stabilisation, plus a new automatic irrigation system. There was also a 3m wide strip of synthetic turf to be installed partially around the oval perimeter, inside the fence.
Stage 3
Excavation and installation
The construction program commenced with the excavation of the existing oval surface area to a depth of 575mm, to remove the existing rootzone layer and the underlying drainage layer.
At this point the base was stabilised, this was an important but also challenging aspect of the construction program, given the underlying site conditions. The principal method was to use a mix of cement and lime. However, the weight impact of the mixing and installing equipment caused further instability to the base profile, especially in areas where moisture levels were elevated. These areas were specifically managed by the contractor by trimming and installing a plastic geogrid with a geofabric backing, called Tensar TX160. This provided acceptable stability and structure to the soft base.
Stage 3
Excavation and installation
After stabilising the existing sub-grade, approved clay material was imported to form a central dome shape over the base with a 0.5% fall towards the perimeter. This started from the centre of the ground around the ‘drop-in’ wicket location but still had to ensure the centre area was flat to accommodate three ‘drop-in’ wicket pods.
The irrigation system was installed prior to the aggregate drainage layer, with the irrigation pipes bedded into the sub-base layer. The irrigation system included 106 valve-in head Rainbird sprinklers - 8005 SS, with over 2510 linear metres of pipe work – including five quick coupling valves (QCVs) strategically placed throughout the oval.
Stage 3
Excavation and installation
Communication conduits were also installed at this time, this was to assist with the cabling of VAR and goal line technology for the appropriate sports, power and communication cables for concerts.
The drainage system was installed after the irrigation installation had been completed and approved, this included Megaflop Lay Flat pipe, both 150mm and 300mm width piping.
The concrete v-spoon drain frames the stadium pitch, which includes 16 drainage pits to take away any excessive water during significant rainfall events.
A blue metal gravel layer was installed across the entire the drainage system. The gravel layer was shaped and trimmed to mirror the domed based while allowing 250mm sand profile to the finished surface levels.
Stage 3
Excavation and installation
The sand specifications play a crucial role in both the integrity and longevity of the stadium pitch.
After an exhaustive process of testing (USGA) individual sands, mixing of various sand blends and ratios. An ideal sand blend was chosen while adapting the specification without impacting the agronomic outcome.
This was an important outcome for the project as sourcing another sand material was cost prohibitive for the City of Launceston.
After sand production commenced, it was stockpiled and transported to the site. During each stage of the project, a series of strict quality control procedures were implemented to ensure transparency and integrity of the bulk sand supply to ensure consistent performance of the sand profile.
Stage 3
Excavation and installation
The sand rootzone profile depth was installed to a depth of 250mm and was applied evenly over the entire surface of the oval. 4298 cubic metres of rootzone material was required. Then the sand profile was consolidated and trimmed to achieve the finished surface contours.
The sand profile was amended with the required nutrients and organic products to ensure the appropriate CEC and nutrient levels.
Prior to the turf installation, a 100-tonne truck was brought on site to install the two drop-in turf wickets. To access the centre wicket location, the underlying sub-base had been reinforced and stabilised during the base preparation operations. This was to ensure there was no sub-base de-stabilisation during the process of installation and also for future use. The playing surface was grassed with reinforcement Transformer turf with turf-type Ryegrass sod grown at the stadium’s turf nursery.
Stage 4
Follow Up
156 days after construction had commenced, UTas Stadium held its first Big Bash match. This occurred on 30 December 2019, with rave review. Quite an accomplishment for all involved.