This thesis aims to document the extent of durability related defects on Queensland’s concrete bridges. Focus has been given to road bridges under the authority of the Queensland Department of Main Roads in the Gold Coast area. Due to their proximity to the coast, these structures will be exposed to the most aggressive environmental conditions. These structures will also experience higher traffic loads and more intense load cycles that those on council roads. The high demands placed on the road network by the public means these structures are integral in maintaining an efficient and fluid road network.
A database was completed, containing 110 concrete bridges. From the reported infected bridge elements and defects, deterioration mechanisms were estimated for affected bridges.
The deterioration mechanisms have been detailed; explaining their process, methods of identification, their extent on the bridge stock and recommendations to minimise the future extent of durability defects
Common repair techniques have been discussed, indicating their suitable application, effectiveness and cost. A case study of two structures highlights the need to select repairs to suit distress levels and local conditions.
The lack of recorded history has prevented the thorough investigation of the durability performance of concrete structures in Queensland. 37% of the concrete bridges in the Gold Coast exhibited signs of durability distress. Furthermore, 50% of bridges in the most aggressive exposure classification are defective and in need of repair. Engineers need to have a sound knowledge of the various distress mechanisms and the ways in which to limit their occurrence on local concrete structures. Particular focus needs to be given to the environmental conditions in which a structure is located, during the initial design stages. Furthermore, strict quality assurance is essential during construction to ensure that these design requirements are achieved.