Our Projects | Allnorth

IN THE MEDIA

We are honoured to see this project featured in the August 2025 issue of Bridge design & engineering magazine. We thank the magazine for permission to make the article available here: “High End Trail Making“, by Iman Soltani Gordfaramarzi

To read the magazine in its entirety, visit bridgeweb.com.

PROJECT DESCRIPTION

The Holt Creek Bridge replacement involved removing a deteriorated 75 m timber trestle and installing a new steel girder pedestrian and multi-use bridge. The site’s steep terrain, restricted access, and environmental sensitivities made conventional crane or pre-demolition approaches impractical. Allnorth designed and implemented an innovative provisional gantry method in which the new steel girders were launched across the existing bridge and later repurposed as a mobile gantry system for demolition, eliminating in-water work and minimizing environmental disturbance.

SCOPE AND DESIGN

Allnorth was retained to deliver full engineering services for the bridge replacement, including:

Permanent Concrete Abutment Modification: Modified abutments to support temporary gantry systems including braced portal frames.
Provisional Gantry System Design: Design of launching and demolition platform trolley and the supporting portals
Analysis of Existing Structure: Analysis of timber trestle under temporary nose occurring during launching of the permanent girders. Analysis included defect analysis and considerations.
Construction Staging: Development of the construction staging and execution plan

The permanent bridge was designed to meet current standards for pedestrian and recreational trail use while also supporting emergency response vehicles such as fire trucks. The structure meets multi-use trail specifications while ensuring durability and low maintenance.

RESPONSIBILITIES