Speaker
Description
Over the past three decades, the application of carbon fiber-reinforced polymers (CFRP) in the post-strengthening of civil structures mainly in the form of externally bonded CFRP sheets and near surface mounted CFRP strips has evolved significantly. While steel tendons still dominate the field of external post-tensioning for the rehabilitation of structures, recent breakthroughs in the application of CFRP tendons will pave the way for their widespread acceptance in rehabilitation. The early 1980s witnessed the pioneering development of anchors for CFRP parallel wire bundles, to addressing the challenges posed by deteriorating steel cables. Notably, the successful application of CFRP parallel wire bundles on the Stork Bridge in 1996 marked a pivotal moment in the history of bridge construction. Shortly thereafter CFRP parallel wire bundles replaced in a post-tensioned concrete box girder bridge corroded steel cables. Despite their early success, their high costs associated with the anchors for CFRP parallel wire bundles posed a significant barrier to widespread adoption. To circumvent this challenge, the introduction of pin-loaded CFRP straps emerged as a cost-effective and reliable alternative. A pivotal point was reached in 2020 when bridge engineers embraced the use of pin-loaded CFRP straps in the construction of network arch bridges. Basic research and development, coupled with comprehensive qualification experiments required by German authorities, confirmed the superior sustainability and cost-effectiveness of CFRP hangers compared to their steel counterparts. The paper meticulously outlines the production process of these tendons and delves into the rigorous qualification experiments that encompass fatigue, fire exposure, and lightning strike tests. Drawing on the successful integration of CFRP tendons in various network arch bridges, this paper envisages their wider use in the economic and sustainable rehabilitation of both concrete and steel structures.
