رفتار خمشی تیرهای فولادی
Abstract
1. Introduction
2. Experimental program
3. Test results and discussion
4. Prediction of flexural strength
5. Conclusions
Declaration of Competing Interest
Acknowledgements
References
Abstract
Experimental research is conducted to investigate the flexural behavior of corroded High Performance Steel (HPS) beams. Four beams with various corrosion damage are designed and subjected to electrochemical accelerated corrosion process. 3D scanning technology is employed to analyze the geometric features affected by the corrosion damage. Flexural tests are carried out, and the impact of corrosion on the flexural response is discussed. Considering the randomness of corrosion pits in each area, predictive models are proposed for the flexural strength of corroded beams with an idealized elastic-plastic and linear-hardening constitutive relationship model. An analysis comparing the proposed models with Chinese and American codes is made. Results show that increasing the corrosion damage leads to a decrease of discreteness in the residual sectional area and causes a transformation in the compressed flange from noncompact to slender. A corrosion loss less than 10% leads to slight deterioration of both strength and stiffness degradation, while further corrosion damage results in a significant decrease. The depth and length of the buckling wavelength for corroded beams decreases gradually as the corrosion damage become more serious. The analytical models IEM and LHM or the GB50017-2017 may be suitable for predicting the lower and upper limit values of the ultimate flexural moment, respectively, and results predicted by AISC are conservative.
Introduction
High performance steel (HPS) is considered to have higher strength, better ductility, and a lower thickness effect than ordinary steel and many significant applications have been carried out because of the exceptional properties of HPS, such as the Minato Ohashi Bridge [1], the Millau Bridge [2], and National Stadium (Bird’s Nest) [3]. Extensive research has been conducted to investigate the mechanical properties of HPS on the basis of material tests [4,5]. Some efforts [6–۸] on flexural ductility and buckling behavior have also been carried out. Felkel et al. [9] conducted monotonic and cyclic tests and computer simulations of HPS 70W girders. Barth et al. [10] evaluated the application of a simplified moment redistribution to hybrid HPS 485W bridge girders in negative flexural region. The above studies of the intact specimen are significant for the HPS application of new structures. Additionally, HPS has various definitions in different countries according to the excellent properties adopted, and this paper focuses on high strength steel. Corrosion is a common deterioration cause in engineering structures, especially for steel members exposed to a wet and salt spray environment [11,12]. For example, it is reported that 15% of the highway steel bridges replacements and some 50% of the railway bridges replacements in Japan were caused by corrosion [13].