Opening reinforcement for box-section walls containing continuous elliptical holes in steel pylons

Abstract

This paper focuses on the reinforcing methods used for improving the compression behaviors of perforated box-section walls as provided in the anchorage zones of steel pylons to hold the cables. The rectangular plates investigated each have single-row continuous elliptical holes and are simply supported on four edges in the out-of-plane direction. Two types of reinforcing stiffeners named flat stiffener (FS) and longitudinal stiffener (LS) are considered. Uniaxial compression tests are first conducted for 46 specimens, of which 10 are unreinforced plates and 36 are reinforced plates. The mechanical behaviors such as stress concentration, out-of-plane deformation, failure pattern, and elasto-plastic ultimate strength are experimentally investigated. Finite element models are further developed to predict the ultimate strengths of plates with various dimensions. The FE results are validated by the test data. The influences of non-dimensional parameters including plate aspect ratio, hole spacing, hole width, stiffener slenderness ratio, as well as stiffener thickness on the ultimate strengths are illustrated on the basis of numerous parametric studies. Comparison of reinforcing efficiency shows that the continuous longitudinal stiffener is the best reinforcing method for such perforated plates. The simplified formulations used for estimating the compression strengths of reinforced plates are finally proposed.