Citation

Balagopal R, Rao NP, Palani GS, Rokade RP. J. Inst. Eng. India Ser. A 2023; 104(4): 867-876.

Copyright

(Copyright © 2023, Holtzbrinck Springer Nature Publishing Group - BMC)

DOI

10.1007/s40030-023-00766-1

PMID

unavailable

Abstract

After erection, the Transmission Line (TL) towers are left with unfilled bolt holes in stub members, which leads to failure due to buckling strength reduction. Thus, the buckling resistance of leg members is crucial in determining the overall stability of TL towers. This paper discusses forensic failure investigation of a 220 kV prototype tested TL tower with unfilled bolt holes in stub members. An analytical expression based on local and flexural buckling interaction, considering the local plate buckling near the vicinity of unfilled bolt holes on the compressive strength of stub member, has been investigated to understand the failure. Detailed component-level experimental, numerical and analytical investigations as per IS 802 (Part 1/Sec 2): 2016/ASCE 10-15: 2015 and BS 8100-3: 1999 standard design specifications have been carried out to simulate stub member failure due to the presence of unfilled bolt holes. Based on these studies, it is observed that premature failure occurred due to the local buckling of stub members with unfilled bolt holes. Hence, to prevent the failure of existing TL towers in the field, it is recommended to fill all unfilled bolt holes in stub members with dummy bolts to ensure their structural adequacy.

Language: en

Keywords

Compression capacity; Failure analysis; Plate buckling; Stub member; Transmission line towers; Unfilled bolt holes