Vol.25, No.2, 2025, pp. 189–192
https://doi.org/10.69644/ivk-2025-02-0189

REPAIR AND STRUCTURAL INTEGRITY ASSESSMENT OF A LARGE SPHERICAL TANK

Nikola Kostić1 , Ivica Čamagić1 , Aleksandar Sedmak2* ,

Snežana Joksić1 , Simon Sedmak3 , Vojin Milić4, Zijah Burzić5

1) University of Priština , Faculty of Technical Sciences, SERBIA

N. Kostić https://orcid.org/0009-0007-9494-5767 ; I. Čamagić https://orcid.org/0000-0003-4706-6333 ;

 S. Joksić https://orcid.org/0009-0002-1909-2462

2) University of Belgrade, Faculty of Mechanical Engineering, Belgrade, SERBIA

A. Sedmak https://orcid.org/0000-0002-5438-1895 , *email: aleksandarsedmak@gmail.com 

3) Innovation Center of the Faculty of Mechanical Engineering, Belgrade, SERBIA

S. Sedmak https://orcid.org/0000-0002-2674-541X 

4) TÜV Rheinland Group, Belgrade, Serbia

5) Society for Structural Integrity and Life, Belgrade, SERBIA

Z. Burzić https://orcid.org/0000-0002-4759-9853 

 

Abstract

Cracks are found during regular periodical NDT (MT and UT) in a large spherical tank, produced in 1974 of low carbon high quality steel of yield strength 385 MPa, similar to A516 Gr.60. Crack length was between 5 and 150 mm, with depth up to 13.8 mm, more than half of vessel thickness (26 mm). Repair was performed in the usual way, by grinding and surface welding. The waterproof testing of the repaired vessel was performed according to standard procedure with additional strain measurements using strain gauges positioned at surface welded regions to assess the vessel structural integrity. Also, acoustic emission was used to follow vessel behaviour during the waterproof test. Since no signal was recorded and strains were linear during the test, it was concluded that the repair was successful, and structural integrity is proved as well.

Keywords: • repair welding • large spherical tank • acoustic emission • strain gauges  

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