This work had to be designed and implemented without compromise to the existing container trade.
CLIENT BRIEF/PROJECT CHALLENGES
The existing timber deck and substructure on the North Mole is deteriorating with age. This project was to design a new concrete deck along with refurbishment of the timber substructure to provide a further 30 years’ service life. In addition, a holistic seismic assessment was undertaken to understand the existing seismic resilience of the backlands, retaining wall and timber piled North Mole Wharf. As the slope of the reclamation is steep it is vulnerable to global slope failure. Seismic performance of the piled North Mole wharf structure is therefore dependent on the seismic performance of the reclamation. As part of our works we have discussed options to improve the seismic resilience of the reclamation and the North Mole wharf structure.
THE SOLUTION
The design of the new concrete deck allowed for the required operational loads of forklifts, Liebherr harbour mobile cranes, HPMV and hoppers. Bollard loads from vessels through the new deck and existing structure were carefully considered. An assessment of the hierarchy of failure with consideration of potential overstrength was undertaken to ensure the bollard bolts were not the weakest element in the load path.
The design was undertaken with consideration of the varying existing levels of the timber substructure when determining the proposed falls for the new concrete deck. Staging of the works was also considered to ensure that container terminal operations would not be affected during the construction works.
OUTCOME/CLIENT BENEFITS
A thorough understanding of the capacity of the existing piles and capping beams and the potential capacity of the deck after strengthening was delivered to PrimePort for use by operations was delivered in a clear and transparent manner. By careful positioning of the outriggers the loads the harbour mobile cranes could lift was maximised without compromising operational requirements.
This work contributed to PrimePort’s risk management by providing an understanding of the vulnerability of the existing structure and how maintenance work on piles could maximise its seismic resilience.
LIST OF PRIMARY SERVICES
- Structural engineering
- Civil engineering
- Durability in marine environment
- Geotechnical Engineering
- Fender and mooring
- Maintenance planning and execution
