关键词: 桥梁工程；钢桥面板；铁基形状记忆合金；钢条加固技术；有限元分析；应力强度因子

Abstract: To achieve active reinforcement of fatigue cracks in the U-rib webs of orthotropic steel decks (OSDs), an arrayed Fe-based shape memory alloy (Fe-SMA) strip reinforcement technique with active strengthening characteristics was proposed, which was based on the arrayed steel strip reinforcement technology. This technique realized active strengthening by introducing prestress into damaged regions. To verify its effectiveness, a finite element (FE) model with damaged steel plate reinforcement was established based on ABAQUS. Based on the proposed model, the influence pattern of key parameters such as steel strip thickness, arrangement spacing, Fe-SMA recovery stress, spacing between bolt holes and cracks, as well as symmetrical arrangement of Fe-SMA steel strips on the reinforcement performance of this technology was evaluated. The research results show the arrayed Fe-SMA strip reinforcement technique significantly reduces the stress intensity factor (SIF) at the crack tip by applying prestress to the damaged steel plate, with reduction ranging from 16.0% to 91.5% compared with the arrayed steel strip reinforcement technique, thereby effectively alleviating stress concentration at the crack tip. Steel strip thickness, arrangement spacing and Fe-SMA recovery stress affect the strengthening performance by influencing the prestress level of the reinforcement system. In contrast, the spacing between bolt holes and cracks as well as the symmetrically arranged Fe-SMA strips have a significant working condition dependence on the reinforcement performance. Under tensile and bending conditions, reducing the spacing between bolt holes and cracks will cause a decrease in the reinforcement performance of this technology, while the opposite is true under shear conditions. The symmetrical arrangement of Fe-SMA strips is beneficial for tensile and shear resistance but performs poorly under bending conditions.

Key words: bridge engineering; steel bridge deck; Fe-based shape memory alloy (Fe-SMA); steel strip reinforcement technology; finite element analysis (FEA); stress intensity factor (SIF)