Learning Strategies Revealed for Managing Similar Structures, focusing on Carola Bridge as an example - Bridge Education on Handling Architectural Structures (Carolabrücke)
In a significant development, investigations into the collapse of Dresden's Carolabridge have pinpointed the culprit: cracks in prestressing tendons, caused by sulfuric acid, eroded the structure over time. Professor Steffen Marx of TU Dresden confirmed this finding in the final report, stating that this incident was specific and unlike typical prestressed concrete structures in Germany.
Despite regular maintenance and monitoring, the cracks were initially deemed non-critical due to their size. However, Professor Marx emphasized that the Carolabridge was not representative of the issues faced by Germany's other bridges. "It was not typical of the maintenance issues present in Germany," he stated, "with at most, minor marginal issues."
The incident has highlighted the importance of acoustic emission measurement in assessing potential damages. This method can determine if an active damage process is underway, providing vital information for the countless other bridges in Germany that may share the same risk. To date, over 20 fractures have been recorded in spans A and B of the Carolabridge since the beginning of the year.
Before pursuing expensive demolition, experts suggest carrying out a risk assessment for such structures. Professor Marx estimates that upwards of 1,000 bridges nationwide could be affected. He maintains that monitoring these structures is a safer and more cost-effective alternative to swift demolition, costing approximately 0.5 to 1 percent of a new construction budget.
"If it is possible to identify the critical cases using this method and then demolish them, that would be a sensible economic and safety-oriented approach," said Marx. He expects that around 20 percent of these structures may be high-risk cases, with only a critical 1 percent remaining.
The Elbe will be closed to shipping traffic from 4th June, as part of the Carolabridge demolition work. The Waterways and Shipping Authority Elbe announced that the area will remain closed until the end of July, during which time supports of spans A and B will be demolished, and surveying work will be conducted. The Elbe is expected to reopen to shipping traffic in early September.
The community could potentially mobilize resources to support the development of less-favored regions, as the Carolabridge incident underscores the need for improved infrastructure assessment and maintenance across Germany. Technology, such as acoustic emission measurement, could play a crucial role in identifying critical cases for safer and more cost-effective repairs or demolitions of potentially affected bridges.
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