On the Issue of the Admissibility of Defects in the Lower Chord of Crane Beams


Crane beams are among the most damaged structures in the buildings with heavy, and very heavy-duty overhead cranes. Their destruction can lead to the death of people working in the workshop, and to significant material losses. The durability of crane structures is determined by the intensity of work of the overhead cranes. The main defects and damages of metal crane beams are regulated by the standard STO-22-05—04, according to which all the cracks in the crane beams are divided into groups according to the risk of destruction. It is believed that the presence of cracks in the lower (stretched) chord of crane beams is unacceptable. Modern methods of non-destructive testing allow to detect defects with a minimum size from 2 mm (ultrasound) to 1 µm (capillary method). These cracks may be due to the inhomogeneity of the chemical composition of the alloy, or be of a structural nature, manifesting itself, in contrast to fatigue cracks that grow in the most loaded areas of the structure, in any part of the lower chord of the beam. 
If any crack is found in the lower chord of the crane beams, it is required to stop the operation of the crane and carry out a major overhaul of the crane runways. However, following these formal rules is not always economically and logically justified. The paper considers an example of rationing by the criterion of non-straining through cracks in the lower stretched chord (cracks of the first group). Based on the criteria of linear fracture mechanics, coefficients are proposed for all steels from which the crane beams are made, allowing for their technical inspection to give an express assessment of the admissibility of the detected through cracks. It is also shown that it is necessary to normalize the permissibility of the parameters of semi-elliptical cracks in the stretched zone (in the lower shelf of the I-beam crane beam), since these cracks can eventually develop into through defects.

1. Vasyuta B.N. Some features of the development of fatigue cracks in the upper zone of the wall of welded crane beams. Izvestiya vysshikh uchebnykh zavedeniy. Stroitelstvo = News of higher educational institutions. Construction. 2003. № 10 (538). pp. 4–13. (In Russ.).
2. Belyy G.I., Kubasevich A.E. The effect of geometric imperfections of the compressed belt on the bearing capacity of crane beams with fatigue cracks in the wall. Vestnik grazhdanskikh inzhenerov = Bulletin of civil engineers. 2022. № 3 (92). pp. 14–20. (In Russ.). DOI: 10.23968/1999-5571-2022-19-3-14-20 
3. Vasyuta B.N. On the empirical dependence for the growth rate of fatigue cracks in the upper zone of the crane beam wall. Izvestiya vysshikh uchebnykh zavedeniy. Stroitelstvo = News of higher educational institutions. Construction. 2004. № 8 (548). pp. 4–11. (In Russ.).
4. Remorov V.E., Bondar D.S. Studying of the intense-deformed condition of crane girders in the presence of cracks. Mashinostroenie = Machine building. 2008. № 18. pp. 164–168. (In Russ.).
5. Takki V.F., Egorov I.F., Tusnina O.A. Increasing the operational life of crane beams. Promyshlennoe i grazhdanskoe stroitelstvo = Industrial and civil construction. 2020. № 12. pp. 61–67. (In Russ.).
6. Vydrin V.N., Zubko O.V. The most characteristic defects and damages of the metal operated crane beams during the expertise of industrial safety. Mezhdunarodnyy nauchnyy zhurnal «Simvol nauki» = International scientific journal «Symbol of Science». 2015. №10. pp. 102–109. (In Russ.).
7. Broek D. Fundamentals of fracture mechanics. Moscow: Vysshaya shkola,1980. 368 p. (In Russ.).
8. Murakami Yu. Handbook of stress intensity coefficients. In 2 volumes. Vol. 2. Moscow: Mir, 1990. 365 p. (In Russ.).
9. Kogaev V.P. Calculations for strength at stresses that are variable in time. Moscow: Mashinostroenie, 1993. 364 p. (In Russ.).
10. Dragunova Yu.G., Zubchenko A.S. Marker of steels and alloys. 4-e izd., pererab. i dop. Moscow: 2014. 1216 p. (In Russ.).
11. V.V. Panasyuk. Mechanics of destruction and strength of materials: handbook in 4 volumes. Vol. 3. Kiev: Naukova dumka, 1988. 425 p. (In Russ.).
12. Ovchinnnikov A.V. Approximate formula for determining stress intensity factors KI for bodies with subsurface cracks. Problemy prochnosti = Strength Problems. 1986. № 11. pp. 41–43. (In Russ.).
DOI: 10.24000/0409-2961-2023-6-23-28
Year: 2023
Issue num: June
Keywords : техническое обследование defect tolerance crane beam defectiveness rationing linear fracture mechanics through crack defect non-breaking criterion
  • Kornilova A.V.
    Dr. Sci. (Eng.), Prof. of the Department, anna44@yandex.ru Moscow State University of Civil Engineering, Moscow Russia
  • Safina L.Kh.
    Cand. Sci. (Eng.), Assoc. Prof. of the Department Moscow State University of Civil Engineering, Moscow, Russia