Permanent bridge rebuilds

Feasibility study

A feasibility study has been conducted to assess and comprehend the distinct engineering challenges linked to each potential bridge crossing location. The study aims to propose bridge concepts that are achievable from an engineering standpoint.

The first three bridge sites identified as priorities are Puketapu, Matapiro, and Waiohiki/Redclyffe. Notably, there are specific financial and time-related limitations associated with the Puketapu and Matapiro sites, which are crucial for swiftly reconnecting these communities. 

The feasibility study serves as an initial foundation, with the intention of subsequently integrating insights and discussions from both mana whenua and the broader community into the bridge design process. This collaborative approach ensures that the final design not only meets engineering criteria but also aligns with the aspirations and needs of all.

Design considerations

The bridges which were destroyed in the Hastings District were designed before the 1960s. These were conceived in an era when our knowledge and practices regarding design, construction, and maintenance were not as advanced as they are today. We have since made significant strides in these areas, and this progress informs the planning and development of our new bridge structures.

Contemporary design standards are now equipped to accommodate even the most challenging weather phenomena, such as Cyclone Gabrielle.

The design considerations for the replacement bridges can be summarized as follows:

• Increased freeboard clearance: The new bridges will have a higher freeboard clearance to provide greater space between the bridge and the water during flood events and include climate change adjustments using the current best estimates.
• Longer spans and fewer columns: Whenever feasible, the bridges will incorporate longer spans and fewer columns in the water. This design approach aims to reduce the risk of flow blockage caused by debris and slash during flood events. However, earthquake resilience is still a major consideration.
• Circular columns: Circular columns will be considered in the bridge design to minimize the chances of debris getting trapped at the piers. This helps maintain the river's flow and mauri, or life force.
• Traffic and pedestrian capacity: The capacity to accommodate both vehicular traffic and pedestrians will be a key consideration in the design of all bridge rebuilds, ensuring functionality and safety for all users.

Old (red) vs new design to current standards - Puketapu example