The Gateway Arterial Bridge forms the northbound carriageway of the Gateway Motorway over the Gympie Arterial Road and provides a vital link to the Bruce Highway and North Queensland. During routine inspections of the bridge, cracking was recorded in the bridge halving joints and highlighted a potential risk with the asset due to their condition. Halving joints are recognised internationally as structural details which carry higher than normal risk due to inadequate detailing and vulnerability to deterioration.
A structured process was adopted to investigate and manage the risk associated with the halving joints on the bridge. This included an initial high-level investigation to assess the halving joints and quickly determine any immediate action required, followed by detailed inspections and assessment determine the risk level and the mitigation measures required.
The investigations determined the bridge was operating at reduced margins for the as-of-right and permit vehicles. Short-term operational management measures which included traffic restrictions, special permit conditions, and structure monitoring were implemented to mitigate the risk whilst long term solutions were being investigated.
Strengthening solutions were largely constrained by the alignment of Gympie Arterial Road at the bridge location. Appreciation of the fact that upgrades for the whole intersection would be investigated in the near future, led to the adoption of an interim solution that would allow the heavy vehicle restrictions to be safely and efficiently removed for the remaining service life of the bridge. The scope of works was determined to include strengthening of the pier halving joints and localised realignment of Gympie Arterial Road.
This paper details the process used by AECOM to identify risks, design strengthening measures, develop a structure management plan, and provide ongoing support to the Department of Transport and
