Drayton St Drain Extension

DESCRIPTION OF PROJECT

In-road stormwater supply & installation of 6x stormwater pits, 144m of 600RCP pipe and 15m of 600×400 Box Culverts at minimum grade past existing sewer, water and gas services. Including asphalt sawcutting, demo and reinstatement to match existing. The project included 1 existing pit tie-in and connection to pre-installed infrastructure of an adjacent development under a 200mm gas main.

PROJECT CHALLENGES

Depth of existing Water Main crossings and a 200mm Gas Main crossing was incorrect on the drawings requiring re-potholing and revised design. T&J assisted in providing appropriate design solutions to the problem and successfully installed the new infrastructure despite difficult additional clearance constraints.
Two in-situ Maintenance Holes (MHs) clashed with the alignment of the stormwater in two intersections requiring design changes. These clashes were circumnavigated by splaying (cutting and angling) the Box Culverts in one intersection and installing an additional Pit and 525 Stormpro pipe around the MH in the other intersection saving significant costs of modification/replacement of the MH’s. Design options were provided by T&J for quick review/adaptation and approval by Council & the Designer (TMK) to enable the project to continue at minimal delay.
Existing unmarked DICL water main was required to be removed align the entire alignment and the existing road unexpectedly varied from 40-180mm in thickness. Pedestrian and traffic controls as well as ongoing notification/updates to residents were required and provided throughout the project.

KEY CONSTRUCTION PROCESSES

Determine staging plan for the works for council approval and resident notifications.
Put in place sediment control measures and traffic/pedestrian controls.
Pothole existing services including in situ-conical shaped maintenance holes.
Sawcut, remove and dispose existing asphalt in stages.
Supply & Install pits in stages.
Supply & install 600RCP and 600×300 Box culverts in stages.
Clean & CCTV the infrastructure for defects.
Trim & seal the road to match existing.
Reinstate Linemarking.