Systematic derivation of safety factors for the fatigue design of steel bridges

This paper presents a probabilistic framework to derive the safety factors for fatigue of steel and composite steel concrete road bridges. Engineering models are used for the design and the safety factor is derived in such a way that the design meets the target reliability set by international Eurocode and ISO standards, estimated using measured...

Influence of inspection on the safety of fatigue loaded welded cruciform steel joints - comparison of simplified and advanced crack growth models

Probabilistic fatigue life prediction models of welded steel joints are often used to estimate the level of safety, which is given in terms of the probability of failure or the reliability index as a function of the applied load cycles. Prediction models based on fracture mechanics allow taking into account the effect of inspections on the...

Rivet clamping force of as-built hot-riveted connections in steel bridges

Hot-riveted connections have been widely used in the past for metallic bridges, of which a large part is still in service, making relevant the assessment of their fatigue life. Previous studies have shown that the fatigue behavior of hot-riveted connections depends on many factors; among these, the residual tensile force in the rivets that...

Probabilistic fatigue resistance model for steel welded details under variable amplitude loading – inference and uncertainty estimation

This paper presents a probabilistic fatigue life prediction model for welded details subjected to variable amplitude random loading, using the nominal stress approach. The proposed model makes use of CA S-N curves in combination with the relative damage rule which allows to globally account for load interaction effects, and the damage limit...

Fracture mechanics based fatigue life prediction for a weld toe crack under constant and variable amplitude random block loading—Modeling and uncertainty estimation

Estimation of the Structural Reliability for Fatigue of Welded Bridge Details Using Advanced Resistance Models

This present paper concerns the application of probabilistic fatigue life prediction models based on S–N curves aiming at the estimation of the safety level for a nonload carrying cruciform joint. The safety level is expressed in terms of the reliability index as a function of the number of applied cycles. Estimating the reliability of a...

Simplified contraint-modified failure assessment procedure for structral components containing defects

Two basic procedures are currently available to determine the critical condition of a flawed structure, at which unstable crack extension may occur. The first method based on elastic-plastic fracture mechanics is accurate but requires a time consuming elastic-plastic finite element analysis. The second method estimates the critical condition...

Fatigue life prediction of hot-riveted shear connections using system reliability

Before bolts were invented, hot-riveting was employed as technological process to produce built-up structural members of steel structures. Nowadays, these structures being still in service and susceptible to fatigue failure,they need to be assessed for their remaining service life. To estimate the fatigue life distribution of riveted connections...

Fatigue life prediction of hot riveted double covered butt joints

Many existing steel bridges are constructed by using hot-driven steel rivets as fasteners. It is known that the fatigue strength of these joints depends on their geometry, since it affects the load transfer mechanism and, therefore, the severity of the stress concentration. Attempts have been taken in the past to provide the characteristic...

Uncertainty analysis of constant amplitude fatigue test data employing the six parameters random fatigue limit model

Estimating and reducing uncertaintyin fatigue test data analysis is a relevant task in order to assess the reliability of a structural connection with respect to fatigue. Several statistical models have been proposed in the literature with the aim of representing the stress range vs. endurance trend of fatigue test data under constant amplitude...

Reliability-based fatigue life estimation of shear riveted connections considering dependency of rivet hole failures

Standards and guidelines for the fatigue design of riveted connections make use of a stress range-endurance (S-N) curve based on the net section stress range regardless of the number and the position of the rivets. Almost all tests on which S-N curves arebased, are performed with a minimum number of rivets. However, the number of rivets in a row...

Fatigue damage evaluation using S-N curves obtained by different data fitting methods

This paper investigates the differences in the predicted fatigue life of transverse butt weld joints and cover-plated beams considering statistically based fitting methods on fatigue test data and comparing the results with the S-N relation proposed in international standards. The test data fitting are performed by employing the Least Square...

Fitting fatigue test data with a novel S-N curve using frequentist and Bayesian inference

In design against fatigue, a lower bound stress range vs. endurance curve (S-N curve) is employed to characterize fatigue resistance of plain material and structural details. With respect to the inherent variability of the fatigue life, the S-N curve is related to a certain probability of exceedance, a percentile of the fatigue life. This paper...

Compatibility of S-N and crack growth curves in the fatigue reliability assessment of a welded steel joint. 2nd International Conference on Structural Integrity, ICSI 2017, 4-7 September 2017, Funchal, Madeira, Portugal

Reliability analysis is a crucial phase in assessing the safety status of new and existing structures. One of its applications is to predict the fatigue life of fatigue prone details. Two models are used to formulate the fatigue limit state: S-N curves in combination with Palmgren-Miner damage accumulation rule and linear elastic fracture...