• Steinbock, Oliver
• Teworte, Frederik
• Neis, Bastian

Abstract

In 2020 two of three bridges, which are part of the german<br/>highway road A 648, were strengthened with carbon reinforced<br/>concrete for the first time in Germany. The two superstructures<br/>were erected in the 1970s as a pre-stressed beam. As tendons<br/>a so called -sigma-oval-steel was used, which is sensitive for<br/>stress corrosion cracking. According to German guidelines and<br/>to exclude a sudden failure, it has to be verified if a damage of<br/>the tendons can be seen at the surface of the cross section via<br/>cracks along the superstructure. This -crack before failurecriteria<br/>was not fulfilled for the described superstructures.<br/>With reference to the relevance of the bridges in the local infrastructure<br/>around Frankfurt a. M., a strengthening concept<br/>was necessary. Due to that fact, a strengthening with carbon<br/>reinforced<br/>concrete was identified as an economic and minimal<br/>invasive method. The report on that forerunner project is<br/>divided into three parts. The first part gives an overview about<br/>the bridges and the background on stress corrosion cracking,<br/>added with explanations about the planning steps. The second<br/>part describes the strengthening with carbon reinforced concrete<br/>with a focus on bridges. The following third part goes<br/>further into detail, regarding the construction and the design of<br/>a carbon reinforced strengthening.

Topics

• impedance spectroscopy
• surface
• Carbon
• crack
• steel
• stress corrosion