Fatigue strength of corroded bolted connection

Carlo Pellegrino,Emanuele Maiorana,Paolo Zampieri,Andrea Curtarello

doi:10.3221/igf-esis.43.06

Carlo Pellegrino, Emanuele Maiorana + Show 2 more

Open Access

https://doi.org/10.3221/igf-esis.43.06

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Abstract

This note summarizes some recent investigation results on the behavior of corroded steel bolted joints under uniaxial fatigue loading. Fatigue test specimens, were made up using S355 structural steel plates joined together with preloaded M12 bolts of class 10.9 with a geometry that corresponds to the Δσ = 112 MPa EC3 detail category. The accelerated corrosion process was accomplished using an electrolyte consisting of an aqueous 5% NaCl solution whereby the specimens were treated. In particular, during the corrosion process specimens were repeatedly immersed for 2 minutes in the electrolyte and then removed keeping them 60 minutes long in free air at 35 °C. An atmospheric corrosion in marine-industrial environment is wellrepresented through corrosion test. Fatigue loading tests and surface morphology measurement of uncorroded and corroded specimens were performed and the results were compared.

Highlights

I n civil engineering, the structures most affected by mechanical fatigue are steel railway bridges that are subjected to a large number of traffic load cycles during their service life
Many studies were conducted on the corrosion and fatigue phenomena, there are few publications regarding their interaction in steel bridges
Aim of this paper is to investigate the influence of the corrosive phenomenon on the fatigue strength of a friction type joint made of high strength preloaded bolts (M12 class 10.9)

Summary

INTRODUCTION

I n civil engineering, the structures most affected by mechanical fatigue are steel railway bridges that are subjected to a large number of traffic load cycles during their service life. Sharifi et al [13] studied the notch factor in steel bridges due to corrosion and proposed two functions which could represent fatigue notch factor in terms of average corrosion penetration and time of weathering exposure to compare it with the one obtained for various classes of structural detail as classified in BS 5400. They concluded that the fatigue notch factor could well quantified the effect of corrosion on the fatigue life of steel bridge members. At the end of the procedure, it was possible to perform fatigue tests (R=0) to plot the S-N fatigue curve of uncorroded and corroded specimens

ACCELERATED CORROSION PROCESS

FATIGUE TESTS

Number of cycles

CONCLUSIONS