Advanced Steel Construction

Vol. 11, No. 3, pp. 294-304 (2015)



Kentaro Yamada 1,*, Toshiyuki Ishikawa 2 and Takumi Kakiichi 3

1 Professor Emeritus, Nagoya University, Japan Advisor, Central Nippon Highway Engineering Nagoya, Co. Ltd., Japan
2 Dept. of Urban Management, Kyoto University, Japan
3 JFE Engineering Corporation, Japan
*(Corresponding author: E-mail:
This email address is being protected from spambots. You need JavaScript enabled to view it.)


DOI 10.18057/IJASC.2015.11.3.4



Over 150,000 highway bridges exist in Japan and about 47 percent of the bridges will be over 50 years old in 2026. The Ministry of Land, Infrastructure, Transport and Tourism (MLIT) launched nation-wide projects to inspect and to establish maintenance plans. About one half of the highway bridges were steel bridges with concrete slabs. Due to heavy truck traffics being operated in or between industrial cities, some of which were illegally overloaded, severe deteriorations to concrete slabs and fatigue cracks in steel girders have been observed. Fatigue cracks in orthotropic steel decks were also found. It is urgent to tackle such fatigue cracks observed in welded joints of steel bridges. Various attempts have been made in Japan to repair and rehabilitate such fatigue cracked members. One is to improve fatigue strength of welded joints in existing bridges, and the other is to repair and rehabilitate cracked members. The latter were, for example, re-welding cracked joints, strengthening by using high strength bolted splices, adding glue to cracks, rehabilitating by gluing CFRP. The authors developed a technique, so-called ICR Treatment, or Impact Crack Closure Retrofit treatment, where fatigue cracks was closed by giving plastic yielding at plate surface near fatigue cracks. Since fatigue cracks do not open due to applied stress ranges, the cracks either do not propagate, or propagate much slower, to prolong remaining fatigue life of the bridges. Fatigue tests were carried out on various welded joints to show how fatigue life was improved by applying the ICR treatment to the cracked welded joints.


Keywords:Fatigue test, Welded joint, Crack, Rehabilitation, Improvement


Download PDF: