Open AccessPREVENTION OF METAL BRIDGE SPANS FROM FATIGUE CRACKING
Author(s) -
Sergey Bokarev,
Andrei Usoltsev,
A. I. Sluzhaev
Publication year - 2019
Publication title -
vestnik tomskogo gosudarstvennogo arhitekturno-stroitelʹnogo universiteta
Language(s) - English
Resource type - Journals
eISSN - 2310-0044
pISSN - 1607-1859
DOI - 10.31675/1607-1859-2019-21-4-181-193
Subject(s) - cracking , structural engineering , welding , materials science , forging , stress concentration , residual stress , crack closure , composite material , engineering , forensic engineering , fracture mechanics , metallurgy
At present, more than four thousand metal bridge spans are in operation all over the Russian railway network. Through the years of operation, about thirty types of fatigue cracking were identified. The dynamics of the types Т-9 and Т-10 cracks formation has increased significantly in recent years. The formation and growth of fatigue cracking is influenced by such factors as residual welding stress, stress-strain state of the bridge structure, defects, damages, and non-observing the operation and maintenance standards, bridge location and bridge span structure. At present, neither measures nor repair are performed to prevent fatigue cracking not exceeding 20 mm in length. Only when a creak reaches a certain length, the regulatory documents require to drill a hole at a crack mouth in order to prevent its further development. The hole diameter should be equal approximately to the doubled wall thickness. In order to prevent further crack growth and cover the hole, a high-tensile bearing type bolt is fixed into it, creating a volume stress. As a rule, such a repair is not enough to stop the cracking process. The article suggests a number of measures based on induction heating that allows to prevent cracking (including forging reducing gaps between connecting plates and horizontal sheets in a truss), to carry out repair (crack mouth soldering) and reinforcement (fixing metal plates onto a wall with a hole).