Bulga Culverts

Singleton Council

Client

Inlet Road, Bulga, NSW

Location

After record flooding in July 2022, significant damage to Inlet Road at Bulga required extensive repairs, including replacing washed-out pipe crossings with larger culvert cells and conducting major earthworks to control future flooding.

The Challenge

Due to the record level flooding in July 2022, Inlet Road at Bulga had two sections washed out, causing major damage and leaving no access for residents. Temporary gravel roads were installed to restore access while planning permanent repairs. The challenge included removing the existing multiple cell pipe crossings and headwalls, which had washed away, and replacing them with larger culvert cells. Additional challenges included major earthworks to reshape the land for controlled water flow during future rain events, re-construction of the road pavement, managing ground water during construction, coordinating large concrete slab pours with limited access, and logistical challenges of installing 20 precast culverts under powerlines.

The Solution

The solution involved removing the existing damaged structures and replacing them with 2400mm x 2400mm x 2100mm culvert cells, constructing cast in-situ headwalls, retaining walls, and a top deck slab. Major earthworks were conducted to reshape the land and control future water flow, and the road pavement was re-constructed. Timber piling was used to improve bearing capacity for the culverts, and 20 precast box culverts and 4 cast in-situ headwalls were installed. Positive feedback was received from local residents and council authorities.

Scope of works:

Site management, including subcontractor management, traffic/pedestrian control implementations & managing all site HSEQ.
Demolish and remove all existing concrete structures and debris from the washed-out areas.
Bulk earthworks to re-shape the creek for directed flow.
Timber Piling to improve bearing capacity for the culverts.
Structural base and roof slabs of the culverts.
Install 20 x 2100 x 2400 precast box culverts and 4 x Cast in-situ Headwalls.
Construct road pavements to tie into the existing road.
Guardrail, signage & line marking.