Abstract:
Precast pre-tensioned concrete bridge construction became common in New Zealand in the 1950s and bridges of this type account for approximately 20% of the State Highway bridge stock. Most of these bridges do not meet today’s durability requirements and as such many are at risk of chloride induced pre-tensioned reinforcement corrosion, which has immediate structural implications. An assessment of the New Zealand pre-tensioned concrete bridge stock is presented and bridges at risk of pre-tensioned reinforcement corrosion are identified. A ‘Distribution and Exposure Classification Tool’ was developed using Google Earth to visualise the State Highway pre-tensioned bridge stock and to estimate exposure classifications for each structure. Physical inspections were performed on 30 representative bridges located across New Zealand and the results were applied back to the bridge stock.