MARINE
“With the rapid growth in the resources sector, containerised trade in developing economies, urban encroachment on existing port facilities and the impact of possible rising sea levels, GHD marine services provides integrated management, engineering, environmental and logistics modelling solutions.”
Ian Dawson
Marine
Business Stream Leader
CALLIOPE SOUTH WHARF ACCESS JETTY
GHD has delivered Cathodic Protection (CP) repair services to the Calliope South Wharf Access Jetty in Devonport, New Zealand.
Owned by the Royal New Zealand Navy (RNZN), the access jetty is a pre-cast pre-stressed reinforced concrete structure built in 1982 that connects the outer wharf to the landside base.
The pre-stressing tendons of the main beams of the jetty structure were found to be suffering from corrosion, due to high concentration of chloride ions from the surrounding environment and low concrete covers. The RNZN sought a long-term solution to the deteriorating concrete elements to avoid repetitive repairs.
As the consulting engineer for this project, GHD undertook investigation, prepared cost estimates for various repair options, detailed CP specification and assisted the RNZN in the tender evaluation and construction processes.
Applying Cathodic Protection to a pre-stressed concrete structure is not a common solution. However, due to the likely disastrous nature of failure of pre-stressed concrete structures if corrosion is unabated, a long-term repair solution such as CP was adopted.
Our team in Sydney was responsible for this project and has since been commissioned to monitor the CP system on a regular basis.
LAKES ENTRANCE SAND MANAGEMENT PROGRAM
Gippsland Ports engaged GHD to provide engineering advice, research and design for the Lakes Entrance Sand Management Program (LESMP), to keep the entrance environmentally sustainable and open for commercial and recreational vessels in the long-term.
Located in Victoria, the Gippsland Lakes consist of a network of five rivers and four lakes covering approximately 400km2. The entrance provides access to Bass Strait through a man-made opening constructed in 1889. Today, Lakes Entrance is home to Victoria’s largest commercial fishing fleet and plays an important role in the economy of East Gippsland. For this reason, keeping the entrance open is critical to the viability of the fishing and recreation industries.
Historically, sand management has involved dredging material from within the inner channels and the bar, by either side-casting or pumping this sand through a sand transfer system to a beach discharge point east of the entrance. Despite a persistent dredging program over the past 25 years, there has been a net accumulation of sand both on the bar and within the inner channels.
The LESMP is a project sponsored by the Victorian Government that comprises the trial of a sand bypass system, trial of a trailing suction hopper dredge, specification for a new dredge, refit of the sand transfer station, and monitoring, all of which involve GHD. The LESMP is on schedule for completion in 2010.
