Experimental Study on the Overall Stability of Corroded H-Shaped Steel Beams

Abstract

The degradation of the overall stability of corroded rolled H-shaped steel beams under bending conditions has not been extensively studied. In the present study, monotonic tensile tests and overall stability tests were conducted on seven rolled H-shaped steel beams that were subjected to electrochemical corrosion in order to discuss the influence of corrosion on the material’s mechanical properties and the overall stability of steel beams under bending conditions. The test results have indicated that the strength, the elastic modulus, and the elongation of the steel declined with an increase in the corrosion rate of the steel beams, and an obvious plastic deterioration phenomenon was observed. In addition, all of the steel beams with different degrees of corrosion were subjected to overall flexural–torsional buckling failure. The stiffness and the overall stability ultimate bearing capacity of the corroded steel beams decreased with the increase in the corrosion rate, and the overall stability of the test beams with a high design corrosion rate degraded significantly. Furthermore, by using the finite element numerical simulation analysis software ABAQUS, a double-reduction corrosion model of the sectional dimensions and the material’s mechanical properties was established. The overall stability ultimate bearing capacities of the steel beams that were subjected to three-point bending and the corresponding load–lateral displacement curves were analyzed. In addition, the finite element numerical simulation results were compared with the test results for verification. Subsequently, the influence of the initial bending on the overall stability ultimate bearing capacity of the steel beams was analyzed by virtue of the verified finite element model. This study will provide a test basis for the evaluation of the bearing capacity of existing rolled H-shaped steel members, as well as an experimental basis and finite element model reference for the follow-up study on the degradation of the mechanical properties of the corroded rolled steel members.

Experimental Assessment of Mechanical Properties of Corroded Low–Alloy Structural Steel

“…When the average corrosion rate reaches 20%, the yield strength of the steel decreases by approximately 10%, and the ultimate strength decreases by approximately 8%. The influence of corrosion on the yield strength of the steel is slightly greater than that on the ultimate strength, which is consistent with the results of related studies in the literature [5][6][7][8][9][10][11][12].…”

“…The average percentage of elongation after fracture of the non-corroded steel in this test is approximately 28%. Formula (12) shows that when the corrosion rate of steel is about 12.5%, the percentage elongation after fracture can no longer meet the requirements of the code, indicating that corrosion has had a great impact on the elongation of the steel.…”

“…The main research results based on using the 'average corrosion' as the influencing factor are summarized in Table 4. From Table 4, it can be seen that there are different ways to describe the 'average corrosion', including the weight loss rate [5][6][7]11,12] and volume loss rate [9,10]. The concept of 'average corrosion' is converting random pitting corrosion into general corrosion, which is a relatively simpler and more practical method.…”

“…Garbatov et al [8][9][10] obtained natural corroded and marine-immersed corroded Q235B steel plates to study the influence of sandblasting and the sandpaper cleaning method on their mechanical properties and proposed a bilinear stress-strain model of the corroded steel plates. Other different accelerated corrosion methods, such as mechanical drilling [1][2][3]11], electrochemical corrosion [12] and finite analyses [4,11,[13][14][15], were adopted to obtain pitting corroded steel. Obviously, mechanical drilling and finite element simulation methods simulate pitting corrosion only from the perspective of geometric dimensions, neglecting the impact of chemical composition changes on the mechanical properties of steel.…”

“…Current research on the mechanical properties of corroded steel is mainly focused on mild steel [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15], and a few studies have been conducted on low-alloy corroded structural steel [16,17]. At the same time, studies of the micro-morphology of corroded steel are insufficient, especially the difference of the micro-morphology of corroded steel under different corrosion environments.…”