Publications by Alain Nussbaumer

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Tubular bridge design has to deal with fatigue issues. The fatigue susceptibility of these bridges, composed of circular hollow section profiles welded together in K-joints, is mainly due to stress concentrations, to welding imperfections and to tensile re ...

The fatigue design of bridges under variable amplitude traffic loads is not straightforward. To simplify the task, the current Eurocode provisions apply fatigue load model 3 and damage equivalence factors (lambda). However, the fatigue load model and the d ...

Investigations on the fatigue strength of steel reinforcement bars (rebars) mainly involves fatigue tests with hot rolled (HR) and cold worked (CW) steels. However, in the last few decades, HR and CW rebars were replaced by quenched and selftempered (QST) ...

Under strong earthquake motions, the liquid stored within large unanchored steel tanks can cause rocking and uplift of the tank base from the supporting foundation. Repeated rocking can lead to low-cycle fatigue fractures in the tank base-plate, and ultima ...

This paper clarifies the terminologies used to describe the size effect on fatigue behaviour of welded joints. It summarizes the existing research on size effect in the perspective of newly defined terminologies. It identifies knowledge gaps in designing t ...

Welded circular hollow section (CHS) joints typical to bridge construction have been examined in an experimental, numerical, and analytical study with respect to their fatigue strength. Evidence from this study has indicated lower fatigue strength for join ...

This paper presents the initial findings from a research project initiated in Switzerland with the objective of developing a new traffic load model for highway bridges that quantifies safety reserves more uniformly. The various proposed new load models and their performance when compared to results from traffic simulations are presented. A particular attention is directed towards the full- probabilistic reliability analyses and the interpretation of the results, to demonstrate how these analyses facilita

Following ICOM’s participation in the redaction of a new recommendation for the evaluation of existing railway-bridges, in collaboration with the SBB/CFF, new questions have been raised. Among those, the influence of a welded longitudinal attachment ends shape on its fatigue behaviour was of particular interest. Indeed, this detail has low fatigue strength (as low as detail category 56 according to SIA 263 [SIA 263]) and the possible shape improvements that are given in the code are costly to fabricate. The

This paper presented a new retrofit system for strengthening the stringer-to-floor-beam double-angle connections in a 92-year-old riveted railway bridge in Switzerland, using prestressed carbon fiber-reinforced polymer (CFRP) rods. The strengthening system ...

Beim Überprüfen der Tragsicherheit einer bestehenden Brücke können dank Messungen die zur Berechnung der Beanspruchung entwickelten Modelle kalibriert werden. Im vorliegenden Aufsatz wird ein neues System von Dehnmessstreifen vorgestellt, welches den erforderlichen Zeitaufwand für die Messungen erheblich reduziert. In wenigen Minuten sind das System installiert und die Messungen durchgeführt. Dies bedeutet für den Ingenieur ein neues Werkzeug, das so nützlich ist, wie für den Arzt das Stethoskop. Einige Anw

The aim of this paper is to propose a new framework for assessment of fatigue partial safety factors with focus on steel bridges welded joints. Fatigue resistance S-N curves for constant amplitude (CA) and variable amplitude (VA) loadings are defined using ...

This paper presents a comparative study of the geometrical optimization of mechanical wedge-barrel anchors for prestressed carbon fiber-reinforced polymer (CFRP) rods. Various anchor configurations were simulated using three-dimensional finite-element (FE) ...

This article examines the extent to which post-weld treatment by needle peening can improve the fatigue performance of tubular truss bridges. To do this, the various potential crack sites on several variants of a typical bridge are analyzed using a probabi ...

The weld-induced residual stresses in a tubular planar K-shaped connection made of construction steel grades S355J2H and S690QH are evaluated using three-dimensional finite element models in thermo-mechanical simulation of welding process. Both lumped sing ...

Numerous research studies are available in the literature on strengthening of steel members using carbon fiber reinforced polymer (CFRP) composites. Although it is clear that strengthening using prestressed CFRP plates has several advantages over non-prest ...

This study aims at clarifying the combined effect of different geometric parameters on the fatigue strength of longitudinal welded gusset joints. Statistical reanalyses with an up-to-date database for this detail were thus carried out on larger parameter r ...

The structural solution for cross girder bracings or box girder diaphragms in steel bridges is often made with tubular elements, specially efficient if compression is required for structural behaviour. The connection between the tubular elements and the gi ...

The concept of fracture for material elements at front of a crack for fatigue crack propagation was extended to the fatigue crack propagation of a cracked metallic member reinforced with a composite patch in this paper. From static mechanics and linear ela ...

Alain Nussbaumer

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Influence of welding residual stresses on stable crack growth in tubular K-joints under compressive fatigue loadings

Analytical approach for improving damage equivalence factors

Very high cycle fatigue tests with quenched and self-tempered reinforcement steel bars

On the low-cycle fatigue capacity of unanchored steel liquid storage tank shell-to-base connections

Size effect of welded thin-walled tubular joints

A critical examination of the size effect correction for welded steel tubular joints

Quantification of hidden safety reserves between different highway traffic load models based on probabilistic calibration analysis

Analysis of Stress Concentration at Longitudinal Attachment

Strengthening of Steel Connections in a 92-Year-Old Railway Bridge Using Prestressed CFRP Rods: Multiaxial Fatigue Design Criterion

Ein Stethoskop zum Überprüfen von Brücken

Calibration of partial safety factors for fatigue design of steel bridges

A reanalysis of the fatigue strength of steel plates with holes, for application of the notch stress approach

FE analysis and experimental validation of mechanical wedge-barrel anchors for CFRP rods

Probabilistic fatigue analysis of shop and field treated tubular truss bridges

Numerical investigation of welding residual stresses in planar bridge trusses made of CHS steel proﬁles

The mechanical behaviour of SentryGlas® ionomer and TSSA silicon bulk materials at different temperatures and strain rates under uniaxial tensile stress state

Stress Analysis of Unbonded and Bonded Prestressed CFRP-strengthened Steel Plates

A reanalysis of fatigue test data for longitudinal welded gusset joints in as-welded and high frequency mechanical impact (HFMI)-treated state

Fatigue behaviour of CHS tubular bracings in steel bridges

Modelling fatigue crack propagation of a cracked metallic member reinforced by composite patches