Street bridge above the Deutzer Ring

Planning and tendering of a monitoring concept, as well as metrological accompaniment

Being erected in the year 1959, the prestressed concrete bridge was once conceptualised as a three-span beam. The overburden cross-sections are concrete plates with hollow bodies that are prestressed in longitudinal direction. Over the northern superstructure, two transport lanes lead to the Rhine when moving west. The two transport lanes on the southern superstructure lead into the direction of Kalk.

During the last structural inspections, grave damages were assessed on the whole structure, only leaving the possibility of a restricted passing-by. Due to the fact that a sustainable restoration of the existing structure was no economic option, a replacement construction was planned by the City of Cologne. Hereby, the whole structure, including the substructures and foundations will be demolished and then replaced by a new structure. With its axis, the new bridge structure is situated in the same position as the existing structure.

Further on, in order to ensure the structural stability of the damaged structure, up until the planned construction measures, ZPP planned and tendered a monitoring concept for the bridge structure. Via a targeted supervision of essential parameters, the condition of the bridge could be continually supervised and controlled, far beyond the insights from visual or hands-on inspections, in order to prematurely detect negative tendencies, making it possible to plan and instruct respective remedial measures. This way, the bridge could be operated in hastily for the remaining operating life, despite the sustainability being reduced by pre-existing defects.

With the installation of the monitoring system, the continually, metrological accompaniment as well as targeted evaluations during running operations were processed. Additionally, the system was calibrated at the beginning of the measurements, respectively the reaction of the bridge under a proof load (45-ton-crane) was examined. With the help of these results, alert values were defined, with the structural stability of the structure being guaranteed as long as they stayed within their limits. Subsequently, the live operation was captured, along with targeted evaluations of the decisive parameters. The measurements and evaluations continued by plan, up to the demolition of the northern superstructure in Mid-February 2016.