Monitoring of Field Performance of Longitudinally Cracked Concrete Bridge Deck

This paper presents the performance of an instrumented concrete bridge deck that developed longitudinal cracks that run along the entire length of the bridge. Although the data collected from concrete embedded sensors indicated that the both the deck and the steel structure are still within the allowable limits, the presence of such longitudinal cracks warranted the continuous monitoring of the bridge superstructure to provide global bridge structure evaluation. Additional twelve sensors were installed across the cracks in June 2007 to monitor continuously their opening and closure as well as the differential settlement across the cracks. Over the past two years, the collected data indicate that some cracks have continued to open. In particular the crack along Girder 7 at the edge bay developed a permanent opening of 0.25 mm and a permanent settlement of 0.08 mm. The opening of the longitudinal cracks could be correlated with the lateral bending of the steel girders, which adversely affect their flexural capacity as well as the axial stress in diaphragm members. In addition, the presence of the longitudinal cracks induce shear stress in the transverse steel rebar due to the passage of traffic loading that would affect their fatigue life.