• Journal of Korean Tunnelling and Underground Space Association
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• v.18 no.2
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• pp.165-173
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• 2016

This paper dealt with contents on the performance evaluation of standardized steel and non-standardized steel of lattice girder. Lattice girder is arch type tunnel supports made of structural steel bar and it is girder used to ensure the stability of tunnel by suppressing any transformation of ground as much as possible during tunnel excavation. The performance evaluation of lattice girder can be conducted through bending strength test, tensile strength test and tunnel standard specification specifies that welding structural steel with over 500MPa yield strength shall be used. However, it is difficult to distinguish visually between standardized steel and non-standardized steel onsite if low-quality structural steel is used. Accordingly, this paper conducted performance evaluation of standardized steel and non-standardized steel of lattice girder to point out the issue of deteriorated yield strength of non-standardized steel, while proposed a method of verifying yield strength onsite.