ABSTRACT
Bridge management agencies currently adopt cost effective approaches to facilitate maintenance of their aging and deteriorating bridge assets. One typical approach is based on different levels of regular inspection before making a decision on repair or replacement. In such approach, the defective level of bridge components can be revealed depending on the levels of inspection from quick view (called level 1 or routine) to visual inspection (level 2) and detailed inspection (level 3 or special). Deterioration level of bridge component is expressed through time-varying discrete condition states (e.g. use of 4 condition states with 1 being good and 4 being poor) which are defined by type and severity of structural deterioration and damages at the time of inspection. Concrete Girder bridges are the most commonly used bridge type. However, understanding of the causes and impacts of different level of defection of girder components to bridge performance is limited. For example, cracks are commonly found defects in concrete girders which can be caused by corrosion of reinforcing steels as well as overloading. This study investigates the visual crack patterns on concrete, which are caused by the corrosion of longitudinal reinforcing steel and/or the effect of traffic loading. The outcome of this study can be used to improve the guidelines on level 2 visual inspection of concrete bridges and to assist in training of inspectors.
