Wigram-Magdala Link Bridge: Low-Damage Details for a More Efficient Seismic Design Philosophy

Research on low-damage systems has been significant in recent years. These systems combine post-tensioning, which provides self-centring; and replaceable devices, which provide energy dissipation. Research by the University of Canterbury, New Zealand, on low-damage bridge piers has been used and developed into a real structure: the Wigram-Magdala Link Bridge. This is believed to be the first bridge in New Zealand, and possibly worldwide, to adopt such a system. This paper uses the Wigram-Magdala Link Bridge as a case study to describe the low-damage details adopted. The paper will then discuss the opportunities which exist for future incorporation of low-damage detailing on bridge structures. For example, the unique features of controlled damage, excellent post-damage performance and ease of repair offer the potential for a change in seismic design philosophy. The low-damage connections provide an opportunity to permit controlled and easily repairable damage to occur in a lower return period earthquake than currently allowed. This shift in seismic design philosophy enables a more efficient use of materials, while still preventing collapse of the structure.