Publications de Alain Nussbaumer

Deciphering tensile fatigue behavior of UHPFRC using magnetoscopy, DIC and acoustic emission

Eugen Brühwiler, Alain Nussbaumer, Jian Zhan

To explore the governing mechanism underlying the tensile fatigue behavior of Ultra-high Performance Fiber Reinforced Cementitious Composites (UHPFRC), this study tested eight specimens using four advanced non-destructive measurement techniques. First, mag ...

2025

Models and methods for probabilistic safety assessment of steel structures subject to fatigue

Alain Nussbaumer

The modelling of randomness and uncertainty in fatigue resistance and fatigue load variables are presented in some detail. This is followed by a review of the specifics of reliability analysis for fatigue limit states and a background on the semi-probabili ...

2025

High cycle tensile fatigue behavior of steel rebar reinforced - UHPFRC at high R-ratio

Eugen Brühwiler, Alain Nussbaumer, Jian Zhan

This paper investigates the high cycle tensile fatigue behavior of steel rebar reinforced − UHPFRC elements, at a fatigue load ratio, i.e., R-ratio of 0.3, representative for structural applications. Prior to testing, magnetoscopy is conducted on each spec ...

2025

Model uncertainties in action effects and load bearing capacity calculation in statically indeterminate reinforced concrete structures

Alain Nussbaumer, Aurelio Muttoni, Xhemsi Malja

For the dimensioning and assessment of structures, it is common practice to compare action effects with sectional resistances. Extensive studies have been performed to quantify the model uncertainty on the resistance side. However, for statically indetermi ...

Ernst & Sohn2024

Evaluation des ponts routiers existants avec un modèle de charge de trafic actualisé. Modélisation des dalles de roulement des ponts-poutres (Rapport interne EPFL n° 306891-2). - Édition 2024 V1.01

Alain Nussbaumer

EPFL Ecole polytechnique fédérale de Lausanne2024

Influence of fiber orientation on the high cycle tensile fatigue resistance of Ultra-High Performance Fiber Reinforced Cementitious

Eugen Brühwiler, Alain Nussbaumer, Jian Zhan

This paper quantitatively studies the influence of fiber orientation on the high cycle tensile fatigue resistance of ultra-high performance fiber reinforced cementitious composites (UHPFRC) within and beyond elastic domain. Eight tensile fatigue tests and ...

2024

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

Evaluation des ponts routiers existants avec un modèle de charge de trafic actualisé. Modélisation des ponts bipoutres (Rapport interne EPFL n° 306891-1). - Édition 2024 V1.03

Alain Nussbaumer

EPFL Ecole polytechnique fédérale de Lausanne2024

Evaluation des ponts routiers existants avec un modèle de charge de trafic actualisé. Modélisation des ponts dalles et cadres (Rapport interne EPFL n° 306891-3). - Édition 2024 V1.04

Alain Nussbaumer

EPFL Ecole polytechnique fédérale de Lausanne2024

A WIM-Based Assessment of Multiple Vehicle Presence Effects on Fatigue Damage of Highway Bridges

Alain Nussbaumer, Scott Walbridge, Matthew James Sjaarda

The fatigue provisions for bridge design in North America and Europe are highly simplified for the sake of practical implementation, in comparison with the state of the art in understanding of the true fatigue behavior. Historically, one significant simpli ...

2024

Evaluation des ponts routiers existants avec un modèle de charge de trafic actualisé

Eugen Brühwiler, Alain Nussbaumer, Dimitrios Papastergiou, Numa Joy Bertola, Matthew James Sjaarda, Paola Costanza Miglietta

Office fédéral des routes OFROU2024

Fatigue behavior of transverse attachments under constant and variable amplitude loading from a Swiss motorway bridge

Alain Nussbaumer, Davide Leonetti, Yukina Takai

This paper investigates the fatigue behavior of non-load-carrying transverse welded steel attachments by reporting on an experimental characterization under constant and variable amplitude loading. Fatigue cracks have been monitored using DIC and ACPD tech ...

Elsevier Sci Ltd2023

Exploring the potential of the critical shear crack theory for reinforced and post-tensioned glass beams: Initial analysis and experiments

Alain Nussbaumer, Pieter Christian Louter, Jagoda Cupac

In the evolution of structural glass beam elements, the requirements for post-fracture load bearing capacity and safe failure behaviour have led to the development of reinforced and post-tensioned beams. Maximum bending capacity in the post-fracture state ...

2023

Local relaxation of residual stress in HFMI-treated high-strength steel welded joints subjected to high-peak loads

Alain Nussbaumer

This study investigates the effect of high-peak loads on local relaxation of residual stress and fatigue damage in HFMI-treated high-strength steel welded joints. The finite element simulations are applied to consider the combined effect of geometry, mater ...

Elsevier B.V.2023

New developments on fatigue in Eurocode on steel structures

Alain Nussbaumer

The design rules for the verification of civil engineering steel structures against fatigue are compiled in the European harmonized design standard Eurocode EN 1993-1-9 released in 2005. This design standard is currently under revision, together with all o ...

Elsevier B.V.2023

Computational Investigation of Mode-I Fatigue Crack Growth in CFRP-Strengthened Steel Plates with a Cohesive Zone Model

Alain Nussbaumer

An increasing number of existing steel structures are nowadays at the end of their service lives and most of them are subjected to fatigue loading. To tackle the fatigue problem, carbon fiber-reinforced polymer (CFRP) composites have been proposed and succ ...

SPRINGER-VERLAG SINGAPORE PTE LTD2022

Experimental Study on the Static and Fatigue Behaviour of a New Mechanical Wedge-Barrel Anchor

Alain Nussbaumer

Post-tensioned steel strands have been traditionally used in different prestressed structures such as concrete girders, post-tensioned concrete slabs, cable-stayed bridges, post-tensioned walls, etc. for a long time. However, due to the vulnerability of st ...

SPRINGER-VERLAG SINGAPORE PTE LTD2022

Damage-Based Assessment of the Fatigue Crack Initiation Site in High-Strength Steel Welded Joints Treated by HFMI

Alain Nussbaumer

This study aimed to identify the fatigue crack initiation site of high-frequency mechanical impact (HFMI)-treated high-strength steel welded joints subjected to high peak stresses; the impact of HFMI treatment residual stress relaxation being of particular ...

MDPI2022

Development of a Strengthening System for Riveted/Bolted Steel Connections Using Prestressed CFRP Rods

Alain Nussbaumer

Among different details in old riveted railway bridges throughout the world, connections such as stringer-to-floor-beam double-angle connections are one of the most fatigue-prone details. These connections are subjected to fatigue loadings due to the secon ...

SPRINGER-VERLAG SINGAPORE PTE LTD2022

Flexural behaviour of post-tensioned glass beams: Experimental and analytical study of three beam typologies

Alain Nussbaumer, Pieter Christian Louter, Jagoda Cupac

The concept of post-tensioned glass beams builds on the concrete analogy of the reinforced glass beams. By additionally prestressing the reinforcement in a post-tensioned system, a compressive pre-stress is applied on the glass, enhancing the initial fract ...

2021