Fatigue design and assessment guidelines for high-frequency mechanical impact treatment applied on steel bridges

Abstract

Structural design of bridges in Europe should be carried out in accordance with Eurocode regulations. However, there is no guideline demonstrating how the fatigue design is to be conducted when high-frequency mechanical impact (HFMI) is used to enhance welded joints in steel bridges. The aim of this paper is to present the different design rules and equations and apply them to some example bridges enhanced by HFMI treatment. Fatigue verification of some welded details in these bridges is carried out via either “damage accumulation” or “λ-coefficients” methods in the Eurocode. Four fatigue load models are used in the fatigue verification (FLM3 and FLM4 for road bridge assessment, and LM71 and traffic mix, for railway bridge assessment). The effect of steel grade, mean stresses, self-weight, variation in stress ratios, and maximum stress on the treatment efficiency is considered in both examples. It is found that HFMI treatment causes a significant increase in fatigue lives in all studied cases.

Research on heavy-haul adaptive technology and strengthening measures for existing railway steel bridge

“…Some of them have already exhibited fatigue problems caused by structural defects. Based on the above, research is conducted in three aspects regarding the adaptability of existing railway steel bridges to heavy hauls and strengthening measures (Sun, 2014; Li & Luo, 2013; Walbridge & Liu, 2018; Cui, Zhang, Bao, Kang, & Bu, 2018; Wang, Wang, Duan, Wang, & Zhai, 2019; Li & Zhang, 2019; Zhang & Li, 2017; Wang, 2016; Zhang & Sun, 2019; Liu & He, 2020; Wang, 2018; Guo & Xu, 2017; Li, 2020; Al-Karawi, 2023; Han, Zhao, & Zhang, 2022; Wallin, Leander, & Karoumi, 2011; Han et al. , 2022; Yu, Shan, Yuan, & Li, 2018; Xiao, Luo, Liu, & Wang, 2020):Overall analysis of the adaptability of existing steel bridge structures to heavy hauls.Evaluation of fatigue life for existing steel bridges.Study of strengthening measures for existing steel bridges.…”