Member Project : Aspire Industrial Park : Alder Constructions
CCF QLD is excited to share details on CCF QLD contractor member Alder Constructions’ project, Aspire Industrial Park.
- Rock is being experienced in majority of trenches/excavations for services and footings for retaining wall posts. Large machines (up to 50T excavator) have been brought in to assist.
SCOPE OF WORKS
- Energex overhead HV relocation works completed. There has been discussion between Alder Developments & Energex for over 18 months. Final earthworks and retaining walls under powerlines allowed.
- 11Ha site vegetation cleared
- 125,000m³ of bulk earthworks with cuts in rock up to 6m deep.
- 4500m² of sleeper and panel retaining walls up to 6m in height
- 1000m² Soil Nail & Shotcrete retaining wall structure to 5.5m in height
- Stormwater infrastructure including 80 structures and 250LM of reinforced concrete box culverts
- Sewer pipe works and manholes up to 4.5m deep.
- Water reticulation for fire services and potable water
- Electrical reticulation and street Lighting
- NBN Installation
- 9,500m² bioretention basin area and associated pipework.
The Aspire Industrial Park is an 11ha site which is part of only 67ha remaining in southern SEQ for High Impact manufacturing, business and operations – typically those businesses that have a higher than normal impact on road networks, sewer/water supply networks or create air or noise emissions which may impact upon sensitive land uses such as residential homes.
While this is a typical subdivision and only for 15 lots, the 11ha area of open development along a 660 lineal metre new road and interface is a massive stage. This would be equivalent to building over 185 residential lots, new road and a major park – a huge area for any mid-size contractor.
The site is located at one of the higher areas in Yatala, about 1km from the CUB Brewery west of the M1. It is a 660m long by 150m wide property that rises from Pearson Road to a high point, where high voltage Energex powerlines traverse the site roughly north to south, before the site gently falls west-north-west to Sandy Creek. The Energex powerlines follow the natural land contours along the ridge which runs north-north-west (of course).
To maximise the useable space, buyers demand maximum use of their land, so the team at Alder Developments specified a vertical wall requirement and a minimal stormwater requirement to all of the subdivision.
A couple of wall systems were explored, such as:
- Geotechnical testing was undertaken to determine if the rock was suitable to “stand up”. While the rock (metasilststone and metasandstone) was encountered at depths from half a metre onwards, the weathering and strength was insufficient to accommodate steep batters, so a system of anchoring and shotcrete wall was devised, up to 7 metres across the site boundaries and typically 3-4 metres in length. This is important as a batter would have created unusable land area which otherwise had a value of $305/m².
- A buttress system was briefly explored, but this was only marginally better than a battered wall.
- Given the rock was sufficiently hard, a shotcrete system was suitable for non-load bearing boundary walls, adjoining an existing property to the south of the site that had no loading impact directly on the boundary.
- A steel post and concrete panel wall (large sleeper format), anchored back to the ground with giant concrete blocks (“dead-man”) was the most suitable and cost balanced system. Alder Constructions worked with Edge Consulting to ensure those walls were also able to accommodate the weight of a building on top of the wall, or heavy vehicle manoeuvring next to the wall.
- Sandstone boulder walls were also not suitable given the area needed for the boulders, backfill and clearance for structures, it was determined too much land was wasted (between 2-5 metres wide) to be suitable for land purchasers.
The rock (as advised in the Geotech reporting) was “super” hard near the top of the ridge of the site, under the powerlines (link between electromagnetic radiation and hard rock!) and the use of 40 tn rock breaking excavators was necessary for over 300m of trenching.
The Energex HV transmission lines needed to be vertically re-aligned to allow useable space under the newly earth-worked subdivision. This is non-contestable Energex work which required careful planning and coordination between Alder Constructions and the Energex teams, to create flat pads for new pole install, cranage pads as well as clearance to natural ground.
The stormwater solutions on this site accommodate the latest policy requirements from Gold Coast Council. The structures and drainage channels cover a significant area up to 4 metres deep. The project needs to accommodate heavy vehicles which meant sections of stormwater had up to 250 metres of reinforced box culverts.
The final piece of the civil works puzzle has been a detention basin which covers 9,000m² and will be an asset handed over to Gold Coast Council when completed. This basin is an enormous structure, with specific flow requirements and finish that is expensive.