Seismic Assessment and Upgrade of Concrete Wharf Structure

The KiwiRail's Inter-island Resilient Connection (iReX) program aims to increase the capacity and efficiency of ferry between the north island and the south island of New Zealand. It introduces two new ferries and terminals at Kaiwharawhara in Wellington and Waitohi Picton. The terminal upgrade for the Picton port involving the construction of a new wharf and the upgrade of the existing wharfs. This paper presents the upgrade work for the largest wharf at the current Picton terminal. The upgrade involves partial demolition and replacement of the wharf deck. New pile supports will also be constructed for the new decks. A mechanical hinge bridge and automatic mooring unit will be installed on these new decks, enabling the operation of new ferries with various sizes. A seismic analysis was conducted to evaluate the seismic performance of the wharf before and after the upgrade work. It was acknowledged that the existing pile might fail in tension or compression due to the additional seismic force. Therefore, the design of the new members allowed the potential uplift movement of the existing piles such that all tension demand will be resisted by the new piles. A finite element model was constructed. Tensionless springs were used during the modelling of the existing piles. The seismic behaviour of the wharf and the evaluation of the wharf performance will be presented.