Structural health monitoring systems for bridge decks and rehabilitated precast prestress concrete beams

Bridges are an integral part of a highway network and represent a multi-billion dollar investment. It is imperative that they are always open to traffic, resistant to natural disaster, and undaunted by millions of loading cycles per year. However, bridges are expensive to maintain and do occasionally fail. Early signs of deterioration are often not seen because concrete, some type of deck overlay, paint, protective wrap or other bridge components mask them. During service of bridge construction materials are subjected to degradation by aging; concrete cracks and creeps, steel oxides and may crack due to fatigue loading. The degradation of materials is caused by mechanical (loads higher then theoretically assumed) and physico-chemical factors (corrosion of steel, penetration of salts and chlorides in concrete, freezing of concrete etc.). As a consequence of material degradation, the capacity, durability and safety of structure decrease. Structural health monitoring is the diagnostic monitoring of the integrity or condition of a structure. The intent is to detect and locate damage or degradation in structural components and to provide this information quickly and in a form easily understood by the operators or occupants of the structure. In this study, a long-term structural health monitoring program was developed to identify any changes in the condition of the rehabilitated precast prestressed beams with CFRP over time due to sustained loads, traffic loads, and environmental exposure and to examine the performance of full-scale precast bridge deck under static and fatigue loading.