Publications associées à Calibration of partial safety factors for fatigue design of steel bridges

Boosting likelihood learning with event reweighting

Andrea Wulzer, Siyu Chen, Alfredo Glioti

Extracting maximal information from experimental data requires access to the likelihood function, which however is never directly available for complex experiments like those performed at high energy colliders. Theoretical predictions are obtained in this ...

Springer Nature2024

Strain-based analysis on the influence of local undercut geometry on fatigue crack initiation life

Alain Nussbaumer, Heikki Tapani Remes, Abinab Niraula

The local undercut defects at the weld toe provide a potential initiation site for fatigue cracks and significantly impact the structure's fatigue strength. The influence of continuous undercut depth on fatigue performance is widely studied, but the resear ...

2024

Geometric tolerances of welded connections with inelastic panel zones

Dimitrios Lignos, Andronikos Skiadopoulos, Ce Wen

Prequalified beam-to-column connections in steel moment resisting frames usually concentrate inelastic deformations in the steel beam ends. As such, nonlinear geo-metric instabilities (i.e., local buckling) may occur in these regions at modest lateral drif ...

Ernst & Sohn2023

The new Chapter 9 of Eurocode 8 Part 3 for Seismic Assessment of Existing Steel Structures

Dimitrios Lignos

The seismic assessment of existing steel structures necessitates the development of practice- oriented engineering models for use in nonlinear static and dynamic analysis procedures. These models should encompass the full range of the anticipated nonlinear ...

2023

Experimental Investigation of Instability-Free Welded Moment Connections With Simplified Weld Details

Dimitrios Lignos, Andronikos Skiadopoulos

In capacity designed steel moment resisting frames, inelastic deformations are mostly concentrated in the steel beams and the column fixed ends of the first story. This design concept limits the participation of the column web’s panel zone in the energy di ...

2023

Experimental Investigation of the Inelastic Cyclic Behavior of Concrete-Filled Double-Skin Tubular Beam-Columns with Corrugated Inner Skins and Ultrahigh-Strength Corner Tubes

Mojtaba Farahi, Dimitrios Lignos

This paper presents the experimental results from nine full-scale concrete-filled double-skin tubular (CFDST) beam-columns. The test specimens exploited two fabrication strategies, featuring either hollow steel inner skins with corrugated geometry or ultra ...

ASCE-AMER SOC CIVIL ENGINEERS2022

Full-scale testing of European steel beams with reduced beam section under reversed cyclic loading

Dimitrios Lignos, Hiroyuki Inamasu

Steel beams with reduced beam section (RBS) are often used as part of prequalified connections in seismic regions. However, RBS connections are not as common in Europe. Reasons relate to easiness in fabrication, which requires on-site welding, and the seis ...

Springer Nature2022

Enhancement of riveted steel bridges by adding a trough in UHPFRC acting in composite action

Eugen Brühwiler

Riveted railway bridges are commonly considered as being “old”, having fatigue damage and are therefore replaced. While this practice should be by now obsolete by using novel engineering methods like structural monitoring, prolongation of the service durat ...

Taylor & Francis2021

Reduced-order Models for Simulating Coupled Geometric Instabilities in Steel Beam-columns Under Inelastic Cyclic Straining

Alexander Riley Hartloper

Numerical models that can simulate coupled geometric instabilities in steel beam-columns are required for the seismic assessment of certain steel moment-resisting frames. Reliably simulating coupled instabilities requires that the steel material is precise ...

EPFL2021

Cyclic metal plasticity model parameters with limited information: a constrained optimization approach

Albano António De Abreu E Presa De Castro E Sousa, Dimitrios Lignos, Alexander Riley Hartloper

Tensile test data for structural steels are ubiquitous. Yet, the information monotonic loading provides with respect to the material's characteristics is limited. Notably, features of inelastic response to cyclic loading, such as the Bauschinger eect, can ...

2021

Probabilistic and deterministic full field approaches to simulate recrystallization in ODS steels

Roland Logé, Flore Villaret

Mechanical and functional properties of Oxide Dispersion Strengthened (ODS) ferritic/martensitic steels are strongly related to their microstructures. Thus, numerical modeling of microstructure evolution during ODS forming is of prime importance. In this w ...

ELSEVIER2020

Steel column stability and implications in the seismic assessment of steel structures according to Eurocode 8 Part 3

Dimitrios Lignos, Alexander Riley Hartloper

Seismic performance assessment of new and existing steel structures based on nonlinear static (pushover) analysis necessitates the use of engineering‐oriented models that trace the nonlinear response of structural steel elements under static and cyclic loa ...

2020

Multiaxial fatigue analysis of high-strength steel welded joints using generalized local approaches

Martin Antonio René Garcia

The objective of this thesis is to improve methods for predicting the fatigue life, multiaxial or not, of mild- and more particularly high-strength steels using local approaches that have the capacity to be applicable to almost any cases, hence the term ge ...

EPFL2020

Fiber-based hysteretic model for simulating strength and stiffness deterioration of steel hollow structural section columns under cyclic loading

Dimitrios Lignos

An efficient component model has been developed that captures strength and stiffness deterioration of steel hollow structural section (HSS) columns. The proposed model consists of two fiber-based segments at a member's ends along with an elastic segment in ...

2020

Performance of Embedded Bolt Shear Connectors

Scott Walbridge, Matthew James Sjaarda

A laboratory research program carried out at the University of Waterloo featured the testing of three large-scale steel-concrete composite beam specimens with embedded bolt shear connectors. A detailed assessment of the connector performance was made, faci ...

TAYLOR & FRANCIS LTD2020

Recommendations for Improved Welding Procedures for Thick Steel Plates Through Thermo-Mechanical Analysis

Dimitrios Lignos

Welding of steel plates is accompanied by residual stresses that increase as the constraint provided by the welded components becomes greater. Consequently, crack initiation has been reported after welding thick plates due to the high residual stresses dev ...

2019

Multiaxial ultra low cycle fatigue in welded high strength steel structural components

Alain Nussbaumer, Albano António De Abreu E Presa De Castro E Sousa

Extreme events often subject regions of structural steel components to large inelastic strains. In conditions such as earthquakes, exceptional winds gusts or tides the loading scenario is cyclical, variable amplitude and frequently multiaxial in nature, an ...

2019

Residual stresses of friction melt bonded aluminum/steel joints determined by neutron diffraction

Jean-Marie Drezet

Near interfacial residual stresses are investigated in a joint composed of aluminum alloy and dual phase steel. A small step neutron diffraction scan was initially performed to determine the weld interface position along the measured transverse cross secti ...

ELSEVIER SCIENCE SA2019

Strain-based approach to fatigue crack initiation on high-strength-steel welded joints under multiaxial loading

Alain Nussbaumer, Martin Antonio René Garcia, Heikki Tapani Remes

A recently novel strain-based approach recently proposed by Remes (Remes 2013) for the fatigue strength modelling of welded steel joints is extended here to consider multiaxial loading conditions and three dimensions finite element models. Only the first s ...

CRC Press (Taylor & Francis)2019

Contributions to Likelihood-Based Modelling of Extreme Values

Léo Raymond-Belzile

xtreme value analysis is concerned with the modelling of extreme events such as floods and heatwaves, which can have large impacts. Statistical modelling can be useful to better assess risks even if, due to scarcity of measurements, there is inherently ver ...

EPFL2019