Bridge 229 NIMT has been for some time the only bridge structure supported on timber piers in the Upper North Island region of the North Island Main Trunk (NIMT). For KiwiRail it is a major milestone to replace the timber piers and steel plate girder structure which is at the end of its service life with a with a new bridge structure. Replacement of Bridge 229 has not only addressed a maintenance prone timber substructure, but has allowed KiwiRail to upgrade the vertical load carrying capacity from 18T to 25T axle loading and upgrade a direct fix deck structure to a ballasted deck for ease of track maintenance.
In an joint presentation the design and construction team will provide an insight into the conceptual and detailed design of the replacement bridge and the on-line construction of the replacement bridge with collaboration between designer and constructor being a key factor in the successful project outcome, involving a 36 hour Block of Line in which the new post-tensioned trough deck was slid into place. The presentation will highlight the key constraints of on-line bridge replacement and provide examples of how these constraints were addressed during the design and construction phase of Bridge 229 NIMT.
Ronald Wessel is an Associate Bridge Engineer at Beca Limited with New Zealand and UK Chartered Engineer qualifications and 15 years of experience in civil engineering structures including extensive involvement in post seismic rail bridge repairs within NCTIR and rail bridge replacements across the North Island.
Adam Buckland is an Engineer at Fulton Hogan with a Bachelor degree in Civil Engineering and has worked in the construction industry for 10years in largely structural projects, including the Waterview Connection tunnel and the Christchurch Rebuild