Statistical Analysis of Pit Depths of Corroded Post-Tensioned Strands According to Different Chloride Condition in a Real Bridge on Service
Seung Hee. Kwon1, Seon Doo. Jo1, Chul Young. Kim1
1 Myongji University
116 Myongji-ro, Cheoin-gu, Yongin, Gyeonggi-do, South Korea
kwon08@mju.ac.kr
seanjo@mju.ac.kr
cykim@mju.ac.kr
Abstract. Since 1990s, as the damage and corrosion of strands were found in some post-tensioned bridges in Europe and the United States. The corrosion-induced failure of strands can causes problems for the structural safety and durability of the bridges.
In February 2016, fracture of external tendon occurred due to corrosion of strands in a 17-year old post-tensioned bridge on service in Korea. In order to investigate the causes of the fracture, strand specimens and grout sample were collected from the position of actual fractured tendon and its vicinity, and pit depths of the strand specimens and acid-soluble chloride concentration of the grout sample were measured.
The higher the concentration of chloride in the grout, the higher probability density for the larger pit depth of corroded strands. The acid-soluble chloride concentration was a major factor influencing the pitting corrosion of the strands.
Keywords: Post-tension, strands, corrosion, pit depths, statistical analysis.
