Distortion-Induced Fatigue Reassessment of a Welded Bridge Detail Based on Structural Stress Methods

Vencislau Quissanga,José Da Silva,Rui Calçada,Abílio De Jesus,Guilherme Alencar

doi:10.3390/met11121952

Vencislau Quissanga, José Da Silva + Show 3 more

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https://doi.org/10.3390/met11121952

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Abstract

Typically, bridge structural systems are affected by random loads that can cause significant damage. One challenging problem in this field is the high-stress amplitude associated with distortion-induced fatigue. In this study, the hot-spot method and the master S-N curve method were validated for the evaluation of fatigue resistance induced by distortion in welded joints of steel bridges. Validation of the master S-N curve method in this research was a necessary prior step for application of the method in real case studies of road bridges, which will be subject to loads of variable amplitudes in the near future, ensuring the basis for the application. The method of validation was based on an important available full-scale fatigue test database, which was generated decades ago to serve as the foundation for the assessment of distortion-induced fatigue. Modelling was carried out based on the finite element method with the aid of ANSYS software, considering the shell and solid elements and equivalent structural stresses. The experimental results were compared with the numerical ones obtained with the two methodologies, and the difference, in terms of global and local tension, was less than 1%.

Highlights

The fatigue phenomenon in welded connections, which significantly affects the useful life of metallic structures, is an important case study in the field of structural engineering.This phenomenon is caused by cyclic loadings capable of causing the failure of a structural element at lower stress levels compared to the strength limit of the material itself [1,2,3,4,5,6].The fatigue life of welded bridge structures subjected to dynamic loading is governed by the fatigue behaviour of their joints [7]
Two methods were validated for the assessment of distortionIn the present study, two methods were validated for the assessment of distortioninduced fatigue strength in metallic bridge welded details using shell/solid finite element induced fatigue strength in metallic bridge welded details using shell/solid finite element modelling and structural equivalent stresses
The hot-spot stress method has already been extensively validated for different types of loading and weld geometries in already been extensively validated for different types of loading and weld geometries in the literature, to our knowledge, this paper highlights the first application of the master the literature, to our knowledge, this paper highlights the first application of the master

Summary

Introduction

The fatigue phenomenon in welded connections, which significantly affects the useful life of metallic structures, is an important case study in the field of structural engineering.This phenomenon is caused by cyclic loadings capable of causing the failure of a structural element at lower stress levels compared to the strength limit of the material itself [1,2,3,4,5,6].The fatigue life of welded bridge structures subjected to dynamic loading is governed by the fatigue behaviour of their joints [7]. Existing design procedures (on fatigue) provide recommendations for mitigating the effects of distortion-induced fatigue caused by differential vertical movements between adjacent longitudinal girders under traffic loading, but do not directly address secondary out-of-plane strains, nor provide guidance for determining the magnitude of out-of-plane stresses in beams. In this sense, distortion-induced fatigue cracking results from second-order stresses, typically due to out-of-plane deformations and incompatible deformations at intersecting structural elements [5,9,10]

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