14m long Cattle Underpass Plus Access Races
Client: Ross Burnett
Project Manager: James Christensen
Job No.: 6682
Site Supervisor: James Christensen
Key features of the work and/or statistics:
- Final size was 3.5m x 2m x 14m
- This was a Design Build project which included liaison with Local Authorities, traffic management, underground services, road reinstatement, roadside drainage, pre-cast concrete installation, QA documentation and health & safety reporting.
Key equipment used:
- Hired Crane
- Trucks and loaders
- Kobelco SK210 & Kobelco SK135 Excavators
- Sakai Roller
- Topcon RTK GPS
Brief description of the work:
A full site survey was conducted by Blackley Construction using our own RTK GPS. This survey included identifying ways to deal with the significant ground water issues as well as the effluent that would be deposited in the box culvert. The survey revealed that the groundwater could be drained through a sand hill into a swale drain approximately 150m away. It also revealed that the effluent could be gravity fed from the underpass to the existing effluent pond which was 700m away. The drainage and effluent pipes would be 6m deep running under the sand hill. A bench was cut through the sand hill so that a 200mm drainage pipe could be laid with a chain trencher to drain the groundwater from around the box culverts. A 200mm effluent pipe was also laid at the same time next to the drainage pipe.
Traffic management was carried out in house by Blackley Construction. With a road closure needed all affected parties were notified prior to the day when the box culvert sections were to be installed. The foundations were over excavated and the box culverts were placed on a 300mm layer of washed stone. Perforated drainage pipe was placed on each side of the culvert so that groundwater could be drained away through the new 200mm pipe. Culvert sections were placed in conjunction with Macintosh Cranes who provided the onsite cranage. Once all culvert sections were installed backfilling was carried out with stockpiled metal. This allowed Blackley Construction to have the road open that night – as required by the Traffic Management Plan. Over the following days work continued off the carriage way by fixing headwalls and the like. Once the headwalls were placed the road was then totally reinstated.
Telecommunication lines were relocated on both sides of the road so that phone lines remained live throughout the installation.