Christchurch City Council Marine Structures Detailed Condition Inspections and Structural Assessments

The specific work tasks included:

• Site inspections – pile and superstructure inspections, to determine the individual structural member and overall condition assessment ratings using the marine structure grading system developed for CCC since 2011.
• Structural analysis – measurement of deteriorated member dimensions to enable structural analysis to the applicable NZ and international marine structure design codes.
• Level of Service (LOS) assessment – determination of whether the desired LOS at each structure was being met based upon its assessed condition and residual structural capacity.
• Residual life forecasting – estimation of the useful remaining service life for each member type and overall structure.
• Maintenance scheduling – development of prioritised repair schedules and cost estimates to maintain each structure in a safe condition for five years.
• Drawings – updating the ‘as surveyed’ CAD drawings of each structure developed for CCC since 2011.
• Reporting – provision of a single inspection and detailed assessment report documenting the findings and repair recommendations for all seven structures.

PROJECT CHALLENGES

• Remote locations and inspection vessel access.
• Tidal working and inclement weather.
• Delivery programme and budget.
• Heritage structures.

OUR APPROACH

• Programming and grouping the tidal inspections to minimise downtime and allow for the geographic spread of the marine structures.
• Appropriately qualified inspection engineers operating to a Maritime NZ accepted plan for commercial vessel usage.
• Trailer-launched inspection vessel for maximum inspection flexibility and efficiency at remote sites.
• Employment of well-established and rigorous marine structure inspection and assessment procedures.
• Regular and close communications with the client, regarding structure specific health and safety issues encountered during the site inspections.

OUTCOME

• Inspections completed to programme during challenging autumnal conditions without incident.
• Reporting completed on time and delivered to the client’s prescribed standards and expectations.
• Project deliverables formed the basis for CCC asset budgeting and future maintenance planning.
  
  

LIST OF PRIMARY SERVICES

• Advisory
• Operations
• Planning
• Asset Management
• Structural Engineering
• Coastal Engineering