Fearnley Drain Culvert Crown Replacement

Key capabilities: Major drainage infrastructure
Project location: Cairns, Queensland
Client name: Department of Transport & Main Roads
Project duration: May 2015 – July 2015
Project value: $2.1 Million

About the project

Fearnley Drain is a tidal waterway running through central Cairns, Far North Queensland. The culvert structure crossing the drain on Mulgrave Road had deteriorated due to the harsh saltwater environment.

In April 2015 Pensar was awarded a contract by the Department of Transport and Main Roads to replace the main structural component of the culvert. Mulgrave Road is a major arterial route with a high volume of traffic (22,000 vehicles per day).

Project scope

  • Demolition of existing three-cell concrete culvert crown units by mechanical means (800 tonnes of reinforced concrete)
  • Installation of 129 new reinforced concrete box crown units (3600x2400mm)
  • Casting insitu reinforced concrete to connect existing stormwater drainage lines
  • Removal and re-erection of street lighting infrastructure and underground cabling
  • Improving a U-turn facility with construction of new unbound pavement
  • Removal of built-up silt and PASS from within the culvert
  • Structure backfill using cement stabilised sand (500m3)
  • Placement of a deep lift asphalt pavement and wearing course
  • Construction of concrete centre median with a coloured pattern finish and concrete public footpaths
  • Installation of temporary waterway barriers to undertake the works in a tidal waterway
  • Management of construction plant to comply with load limit restrictions over Fearnley Drain (existing structure)

Innovations & highlights

Zero harm to the sensitive marine environment through effective management and control of risks.

Positive feedback from local stakeholders during and after construction.

Works constructed under traffic with 22,000 vehicles per day (sixlane divided arterial road) and zero reported traffic incidents.