J.-P Jaspart

• University of Liège

Ελατές διατομές γωνιακών χρησιμοποιούνται από τα πρώτα χρόνια των χαλύβδινων κατασκευών λόγω της εύκολης μεταφοράς και επί τόπου συναρμολόγησής τους. Ωστόσο, οι διατομές αυτές έχουν συγκεκριμένα χαρακτηριστικά (μονοσυμμετρικές διατομές με χαμηλή αντίσταση σε στρέψη και στρέβλωση, επιρρεπείς σε τοπικό λυγισμό, κ.ά.) που τις διαφοροποιούν πλήρως από...

Steel frames subjected to a column removal typically exhibit a complex load resisting mechanism characterised by three contributions: i) beam yielding mechanism, ii) compressive arch, and iii) catenary action. The development of compressive arch actions in the beams bridging over the lost column has not been yet thoroughly investigated in steel fra...

Thin‐walled cold‐formed sections are extensively used as primary structural elements in storage system structures or steel houses, or as secondary elements like roof and wall systems, floor girders, etc. Despite their many advantages, such as transportability and lightweight, these members are usually susceptible to lateral‐torsional buckling as th...

This paper presents a new analytical approach for predicting the plastic resistance of the sheared panel zone in steel beam‐to‐column joints. This approach has been developed within the framework of a larger research project dedicated to the prediction of the full non‐linear behaviour up to failure of the sheared panel zone. It is suggested as an a...

Lattice towers are extensively built in Europe and worldwide to serve power transmission purposes. Their members mainly consist of single angle profiles, while built‐up sections, such as star‐battened ones, are usually preferred for the strengthening of individual members or in case of very high compression loads. Recent upwards developments of the...

Steel angle members are widely used for the construction of lattice towers, mainly because of easy assembly on site and compact transport. Bracing members, especially, are connected directly or through gusset plates to the adjacent members with one or more bolts on one leg only. This type of connection provides some rotational restraint at the ends...

Component‐based mechanical models compliant with Eurocode 3 becomes a popular alternative to complex Finite Element (FE) analyses for characterising the behaviour of steel joints. However, several key aspects are not accommodated by the existing spring models, i.e., group mechanisms, component interactions, and the variation of the shear force on t...

An innovative mechanical model for the characterisation of structural steel joints is presented in this paper. The model relies on the so-called “component method” to simulate the joints through an assembly of extensional springs and rigid elements. The proposed approach solves the inconsistencies met in the existing spring models and allows bypass...

This paper presents the results of 10 laboratory tests performed on closely spaced built-up members fabricated from hot-rolled angle sections. Such members are of special interest in the construction and reinforcement of steel lattice towers used for telecommunication or electrical transmission lines. The angle sections used in this study were star...

The component method is widely used nowadays for the analytical prediction of the mechanical properties (rotational elastic stiffness, design resistance and ductility/deformation capacity) of steel and composite beam-to-column joints. The Part 1-8 of Eurocode 3 (EN 1993-1-8) provides expressions for the evaluation of the properties of many differen...

In the framework of a recent RFCS project, innovative joint solutions named FREEDAM were developed with the objective of proposing beam‐to‐column joints able to dissipate the seismic energy with limited or even no damages. The efficiency of the proposed solutions was validated through experimental, numerical, and analytical investigations on moment...

The built heritage is a collection of properties of heritage value that should be protected and preserved. Designed in Belgium and built in the Democratic Republic of Congo (DRC) at the beginning of colonisation, the steel‐framed houses in the province of Kongo‐Central are in an advanced state of damages due not only to the climatic conditions of t...

Angles profiles have been used since the very beginning of the steel construction due to their easy production, transportation, and ability to be connected. However, they exhibit some specific features that clearly distinguish them from other types of common sections, as they are monosymmetric sections with very small constants in both torsion and...

The roller‐straightening process is a steel cold production technique which consists of passing a steel element through a series of rolls that bend the member, what leads progressively to a reduction of the initial geometrical imperfections along its weak axis. In addition, this post‐treatment process induces a continuous yielding of the steel memb...

The component method is widely used nowadays for the analytical prediction of the mechanical properties (rotational elastic stiffness, design resistance and ductility/deformation capacity) of steel and composite beam‐to‐column joints. Eurocode 3 Part 1‐8 (EN 1993‐1‐8) provides expressions for the evaluation of the properties of many different joint...

This paper addresses the analysis of planar frames with stiff semirigid joints. If they are stiff enough, a concept which is discussed with respect to the local stiffness of the neighboring beams and columns as well as the global flexibility of the whole structure, the joints can be modeled as fully rigid. This makes the structural analysis easier...

Winkelprofile gehören zu den beliebtesten Profiltypen im Bausektor, besonders im Mast‐ und Turmbau. Durch ihre einfache Herstellung und den einfachen Transport, im Zusammenhang mit der ausgezeichneten Anschlussfähigkeit, unterscheiden sie sich von anderen Profilen. Sie werden als Einzel‐ oder zusammengesetzte mehrteilige Profile, letztere mit paral...

Angle profiles are amongst the most common structural steel shapes for construction purposes. However, their specific features clearly discern them from other types of common sections, what inevitably leads to the need for the development of specific design provisions. In this paper, extensive numerical and experimental studies have been conducted...

This article addresses the problem of prediction of the plastic shear resistance of the panel zone (PZ) in welded steel beam-to-column joints under monotonic loading. As a first step, an extensive review of existing analytical models is proposed. The capabilities of the latter are then assessed through comparisons against available experimental dat...

Nominated for the Eurosteel 2021 Best Paper Award This short report has been prepared in the context of the Eurosteel 2021 Best Paper Award. It summarizes developments completed and in progress at the University of Liège designed to characterize the complete shear behaviour of the panel zone in steel beam‐to‐column joints in terms of stiffness, res...

Nominated for Eurosteel 2021 Best Paper Award The paper addresses the instability of large angle columns in high‐strength steel subjected to compression loads. It presents a number of compression tests on such columns with different eccentricities and slenderness and the resulting different buckling failure modes observed. The experimental campaign...

The characterization of the structural behavior of composite beams is directly affected by the determination of the effective slab width. Various codes propose their own definitions of the effective width based on the beam span and the slab width parameters. However, the evaluation of the effective width may be influenced by other parameters. The a...

Robustețea structurală și prevenirea colapsului progresiv sunt cerințe specifice de siguranță, care sunt prevăzute în normele și standardele moderne, inclusiv Eurocoduri. Aceste cerințe necesită o atenție deosebită din partea tuturor profesioniștilor implicați în industria construcțiilor, adică arhitecți, proiectanți, verificatori, constructori sau...

De constructieve robuustheid voor de beperking van progressieve instorting is een specifieke veiligheidsaspect die nu in moderne codes en normen, zoals de Eurocodes, wordt behandeld, die bijzondere zorg vereist van alle professionals die bij de bouwsector betrokken zijn, o.a. architecten, ontwerpers, constructeurs, controleurs en verzekeringsmanage...

Robustnost konstrukce pro zmírnění rizika progresivního zřícení je bezpečnostním hlediskem, které se řeší v moderních předpisech a normách, včetně evropských. Vyžaduje součinnost všech odborníků ve stavebnictví, architektů, projektantů, statiků, konstruktérů, státní správy a pracovníků pojišťoven. Důležitost robustního návrhu zvýraznily události, j...

La robustesse des structures visant l’atténuation de l'effondrement progressif est une considération de sécurité spécifique qui est maintenant abordée dans les codes et les normes modernes, y compris les Eurocodes, et qui exige une attention particulière de tous les professionnels impliqués dans l'industrie de la construction, y compris les archite...

La robustezza strutturale per la mitigazione del collasso progressivo identifica un aspetto specifico della sicurezza considerato dai moderni codici di calcolo e dalle normative, inclusi gli Eurocodici, e che richiede particolare attenzione da parte di tutte le figure professionali coinvolte nell’industria delle costruzioni, inclusi architetti, pro...

La robustez estructural y la mitigación del colapso progresivo es una consideración específica de la seguridad de las estructuras y las construcciones que se empieza a abordar ahora en las normas y los códigos modernos, incluidos los Eurocódigos, y que requiere una atención especial por parte de todos los profesionales involucrados en la industria...

A robustez estrutural e mitigação do colapso progressivo é uma consideração específica de segurança atualmente abrangida pelos códigos e normas modernos, incluindo os Eurocódigos, que requer particular cuidado da parte do todos os profissionais envolvidos na indústria da construção, incluindo arquitetos, projetistas, empreiteiros, fiscais e segurad...

Odporność konstrukcji i łagodzenie skutków katastrofy postępującej to specyficzne aspekty bezpieczeństwa uwzględniane we współczesnych wytycznych i normach, również w Eurokodach. Aspekty te powinny być brane pod uwagę przez specjalistów związanych z branżą budowlaną, w tym architektów, projektantów, konstruktorów, pracowników nadzoru budowlanego, j...

Die Robustheit zur Vermeidung eines progressiven Kollapses ist ein spezifischer Sicherheitsas-pekt, der in den modernen Normen, einschließlich der Eurocodes, thematisiert wird. Er erfor-dert von allen in der Bauindustrie beteiligten Fachleuten, einschließlich Architekten, Designern, Bauunternehmern, Bauprüfern und Versicherungsmanagern, besondere A...

Lattice towers are extensively built in Europe and worldwide to serve telecommunication or power transmission purposes. Their members are usually made of equal leg angle profiles that are bolted at their extremities. Such types of towers are mainly designed to EN 1993-3-1 and EN 50341-1, based on a first-order linear elastic structural analysis of...

Composite steel-concrete columns utilise the advantages of both materials, by combining high strength and ductility of steel with the compressive strength of the concrete. But the wide adaptation of composite structures is limited, mainly because of the lack of cheap and easy to construct connections, as many of which require costly and timeconsumi...

Angle profiles belong to the most common structural steel shapes used in construction. They exhibit specific features that distinguish them from other types of common sections. This paper presents specific rules for the classification of angle profiles as well as formulas for the design cross-section resistances. The rules are based on theoretical-...

The paper discusses the stability behaviour of large angle columns in high strength steel subjected to compression loads. It presents a number of compression tests on such columns that have been performed at University of Liege with different eccentricities and slenderness and, as a result, different buckling failure modes observed. The experimenta...

The present work aims at studying the field of interest of high strength steel rolled sections (fy>460 MPa) for steel structures from an economic point of view. Whilst these high strength steel profiles do not exist yet, steelmakers are able to produce more resistant steels through more efficient production processes and a future emerging of these...

This article addresses the problem of prediction of the plastic shear resistance of the panel zone (PZ) in welded steel beam‐to‐column joints under monotonic loading. Existing analytical models are first critically reviewed through comparisons with available experimental data. These comparisons reveal that none of them is able to accurately capture...

The current paper resumes the design of a steel lattice transmission tower carried out in the framework of the RFCS-funded research project ANGELHY. The scope of ANGELHY is the establishment of analysis methods for lattice towers and the development of design rules for steel and hybrid angle sections, as well as built-up members composed of angles....

Lattice towers are extensively built in Europe and worldwide to serve telecommunication or power transmission purposes. The structural members of such towers are frequently made of equal leg angle sections that are often preferred to tubular sections due to their easy connection that results in a simple erection, a requirement set by most telecommu...

This paper focusses on the buckling resistance of compression members made of back‐to‐back connected angle sections. The studied built‐up members are connected through bolted packing plates. Due to the flexibility of this connection, these members generally do not fully work as a single member but the connection stiffness has to be accounted for. I...

In the framework of the ongoing revision of EN 1993-3-1, the RCFS funded research project ANGELHY has performed experimental, numerical and theoretical studies on angle sections and lattice towers. This paper presents a particular aspect of the ANGELHY project and focusses on a theoretical study concerning the behaviour of angle section members. Fi...

This work deals with the prediction of the bearing resistance of elementary shear connections constituted by gusset plates and square hollow sections fastened with long bolts. The research is motivated by the lack of specific rules in international codes for this particular configuration. In fact, while in lap shear connections, single or double-si...

The stability of columns made of large angle profiles in high strength steel and subjected to centric and eccentric compression loads is investigated through experimental tests, numerical simulations and normative approaches. The aim is to widen the knowledge on such columns and so to complement previous experimental studies that focusing on smalle...

Short- and long- term loss of preloading in slotted bolted connections

Eurocode 3, in its Part 1-8 on the design of structural joints, and Eurocode 4 provide designers with assessment procedures for the initial rotational stiffness and the resistance of steel and composite joints respectively. These design procedures refer to the so-called component approach and have been validated through numerous comparisons with te...

The paper presents some different developments performed in the last years at the University of Liège. In particular, complete component-based analytical procedures to predict the resistance of steel bolted connections subjected to combined bending moments and axial forces (M-N interaction) are introduced and commented. These analytical procedures...

Due to the increase in terroristic attack and catastrophic events, the engineering structures are more and more likely to be subjected to abnormal loading conditions. Moreover, exceptional and unpredictable fatalities (extreme wind actions, explosions, car impacts…etc.) could lead to dreadful consequences, such as the partial or total progressive c...

The « component method » is nowadays recognised by the European codes as the reference method to design and characterise steel and steel‐concrete composite joints. This method, which may be seen as a macroscopic application of the finite element method, consists in dividing the joint into a series of zones through which the forces are transferred,...

Nominated for the Bernt Johansson Outstanding Paper Awards at Nordic Steel 2019 The ”column web panel in shear“ is known to be a key component in the design of steel and steel‐concrete composite joints as it can provide a reserve of ductility at the joint when activated and appropriately designed. Therefore, its behaviour has been studied for years...

Present paper focuses on the critical assessment of the response of an electric transmission tower designed under gravity and wind loads according to available dedicated norms. Available numerical tools are used, with reference to different types of structural analyses. The tower has been initially designed according to the existing rules and under...

Nowadays, modern design norms require to the civil engineer to design robust structures in order to limit the occurrence of failures under exceptional loadings. In steel and steel-concrete composite construction, this request for robustness mainly focusses on the joints between structural members, these joints generally being the « weak » elements...

Much work has been conducted in the past on the influence of the rigidity of structural joints on the behavior of steel frames. Buckling of a column is fundamental to the design of load bearing structures mainly when the analysis of such frames takes into account the effect of the connection flexibility. The present work deals with such an effect o...

Background:Recent catastrophic events have pointed out the need to ensure the integrity of structures under “exceptional” events. Since many years, the University of Liège is involved in different activities and projects related to the robustness assessment of structures. The robustness of a structure is the ability of the system to remain globally...

Backgrounds: The deformation capacity of beam-to-column connections strongly influences the robustness of earthquake-resistant Moment Resistant Frames (MRFs) when subjected to a loss-of column scenario. As a consequence, with the aim of foresee the structural response up to the failure, an accurate modelling of the ultimate behaviour of the joints...

The analysis of steel-framed building structures with full strength beam to column joints is quite standard nowadays. Buildings utilizing such framing systems are widely used in design practice. However, there is a growing recognition of significant benefits in designing joints as partial strength/semi-rigid. The design of joints within this partia...

Cold-formed steel elements are being used more frequently on construction sites because of the good strength-to-cost ratio. Researches on such structures show that, in most cases, the behaviour of the constitutive joints is semi-rigid. However, insufficient studies are published examining the properties of these joints. This paper presents a study...

The analysis of steel-framed building structures with full strength beam to column joints is quite standard nowadays. Buildings utilizing such framing systems are widely used in design practice. However, there is a growing recognition of significant benefits in designing joints as partial strength/semi-rigid. The design of joints within this partia...

Recent catastrophic events have pointed out the necessity of ensuring the integrity for structures under " exceptional " events. Since many years, the University of Liège is involved in different activities and projects mainly related to the robustness assessment of structures. The robustness of a structure is the capacity of the system to remain g...

Robustness of Moment Resistant Frames (MRFs) designed according to current seismic codes and subjected to a loss-of-column scenario is strictly linked to the deformation capacity of beam-to-column connections, which are usually subjected to combined axial and bending loads. In the seismic design of steel frames, once avoided the yielding of columns...

In the framework of a RFCS project entitled " FREEDAM-Free From Damage Connections " , innovative friction connections activated as dissipative zones in case of seismic actions are studied, with the objective to avoid any damage in the structures not only for frequent and occasional seismic events, but also for destructive earthquakes. These fricti...

Recent events such as natural catastrophes or terrorist attacks have highlighted the necessity to ensure the structural integrity of buildings under exceptional events. For more than 10 years, the University of Liege is strongly involved in researches on the response of structures further to such exceptional events through participations to nationa...

Robustness of Moment Resistant Frames (MRFs) designed according to current seismic codes and subjected to a loss-of-column scenario is strictly linked to the deformation capacity of beam-to-column connections, which are usually subjected to combined axial and bending loads. In the seismic design of steel frames, once avoided the yielding of columns...

In the framework of a RFCS project entitled “FREEDAM ‐Free From Damage Connections”, innovative friction connections activated as dissipative zones in case of seismic actions are studied, with the objective to avoid any damage in the structures not only for frequent and occasional seismic events, but also for destructive earthquakes. These friction...

The present work deals with the effect of beam-column joint flexibility on the elastic buckling load of plane steel frames. A simple and effective mechanical model is proposed and the corresponding stiffness matrix is presented. The model consists in the development of comprehensive approach taking into account, simultaneously, the effects of the j...

Recent events such as natural catastrophes or terrorism attacks have highlighted the necessity to ensure the structural integrity of buildings under exceptional events. For more than 10 years, the University of Liege is strongly involved in researches further investigating the response of structures to such exceptional events [1, 2]. The present pa...

Moment-resisting joints is a general term used to cover all joints which transfer significant bending moments between the connected members, but also shear and/or axial forces. These joints may be rigid or semi-rigid, in terms of stiffness, and may exhibit a full or a partial strength resistance level. This chapter first addresses the characterisat...

Fillet welds and butt welds are widely used in construction. They represent 80% and 15%, respectively, of all welds found in structures. For the remaining five per cent, plug and fillet all round welds are mostly used. Butt welds are used between adjacent plates in so-called butt and tee-joints. Contrary to a butt weld, a fillet weld requires no pr...

The basic elements of joints in steel structures are mechanical fasteners like bolts or pins. In steel construction, the most typical mechanical fasteners to connect plates or profiles are bolts, or more precisely: bolt assemblies (sets) including the bolt itself, a nut and one or more washers. The two main categories, dependent on the loading appl...

Simple joints are assumed to transfer no bending moments and should be designed accordingly. This chapter presents various joint configurations where simple joints are likely to be used. They are grouped in five categories: beam-to-column joint configurations; beam-to-beam joint configurations; beam splice joint configurations; bracing joint config...

EN 1993 adopts the component method as a reference for the design of joints in steel structures. This chapter reviews recent developments on the application of the component method to various loading situations, including fire, earthquake, impact and explosion. Guidelines on how to apply the component method for the evaluation of the initial stiffn...

This chapter describes the various approaches that can be used to design steel frames with due attention being paid to the behaviour of the joints. For the design of steel frames, the designer can adopt one of the following design approaches: traditional design approach and integrated design approach. In the traditional design approach, any joint i...

EN 1993-1-8 gives detailed application rules to determine the static design resistances of uniplanar and multiplanar joints in lattice structures composed of circular, square or rectangular hollow sections. Also, uniplanar joints in lattice structures composed of combinations of hollow sections with open sections are covered to a certain extent. Th...

The design of a frame and its components is a two-step procedure involving a global frame analysis followed by individual cross section and member design checks. Traditionally, frame analysis is performed by assuming joints as perfectly pinned or perfectly rigid. It is important that the joints are subsequently designed and detailed to behave in a...

In the framework of a RFCS project entitled “FREEDAM -Free From Damage Connections”, innovative friction connections activated as dissipative zones in case of seismic actions are studied. The main aim of the research is to provide a new joint typology able to withstand not only frequent and occasional seismic events, but also destructive earthquake...

The research into a specific type of unstiffened extended end‐plate joint used to connect I‐shaped beams to concrete‐filled rectangular hollow section columns is presented in this paper. The main idea is to use long bolts passing through the column to connect the beam end‐plates in order to… avoid intermediate connecting elements (e.g. a reversed c...

This book details the basic concepts and the design rules included in Eurocode 3. Design of steel structures: Part 1-8. Design of joints. Joints in composite construction are also addressed through references to Eurocode 4. Design of composite steel and concrete structures. Part 1-1: General rules and rules for buildings. Attention has to be duly p...

This chapter provides design rules i.e., Eurocode 3 Part 1-8 (EN 1993-1-8) for mechanical fasteners. The designer will find here application rules for different types of mechanical fasteners: bolts, injections bolts, anchor bolts, rivets and pins. The very basic connection is composed of a bolt assembly connecting two steel plates. Eurocode 3 disti...

The design of a frame and of its components consists of a two-step procedure involving a global frame analysis followed by individual cross section and member design checks. This chapter recalls the available methods of structural analysis and design, but with a special focus on the integration of the joint response into the whole design process. T...

In the construction field, fillet welds and butt welds are widely used, and plug welds, and fillet all round welds to a lesser extent. Reliability of welding depends on several factors including properties of parent and consumable materials, welding process, tolerances, preparation of surfaces, and storage and handling of consumables. For weld desi...

This chapter expresses the way on how to characterise the mechanical response of the individual components, covered by Eurocode 3 Part 1-8 (EN 1993-1-8). It addresses the assembly procedure problem successively in terms resistance, stiffness, and deformation capacity. According to the component method approach used in EN 1993-1-8, a joint is consid...

This chapter describes the various approaches which can be used to design steel frames with due attention being paid to the behaviour of the joints. The design process is ideally aimed at ascertaining that a given structure fulfils architectural requirements, on the one hand, and is safe, serviceable and durable for a minimum of global cost, on the...

This chapter gives a short introduction to the design of hollow section joints. Eurocode 3 Part 1-8 (EN 1993-1-8) gives detailed application rules to determine the static design resistances of uniplanar and multiplanar joints in lattice structures composed of circular, square or rectangular hollow sections. The design resistance of joints between t...

This chapter presents design rules for beam-to-column, beam-to-beam configurations and column bases. With the aim of establishing a full design approach according to the general design principles stated in Eurocode 3, design sheets for header plate and fin plate connections were so prepared at the University of Liege and discussed at several meetin...

This chapter reviews recent developments making the application of the component method possible to various loading situations, including fire, earthquake, impact or explosion. In Eurocode 3 Part 1-8 (EN 1993-1-8) and Eurocode 4 Part 1-1 (EN 1994-1-1), guidelines on how to apply the component method for the evaluation of the initial stiffness and t...

The aim of this paper is to provide a formulation able to predict the resistance of simple shear connections realized by fastening a plate to a hollow square section by means of long bolts. The research is motivated by the fact that the rules currently provided by EC3 for defining the bearing resistance of steel connections are limited to the case...

The competition in the field of storage racking structures is so that companies are always looking for new structural solutions aiming at containing construction time and expenses. This paper focuses the bearing failure of shear joint using long bolts through thin tubular members with the purpose to check the reliability of Eurocode 3 formulation....

The demand for economic and eco-efficient solutions in construction industry is particularly enforcing efficient design and construction methods. The design of composite construction according to the plastic hinge theory in combination with semi-rigid joints provides one contemporary promising answer to these demands. This combination enables to mo...

An overview of plastic-hinge model for steel frames under static loads is carried out in this paper. Both rigid-plastic and elastic-plastic methods for framed structures are reviewed, including advantages and disadvantages of each method. It concerns both analysis and optimization methodologies. The modeling of 3D plastic hinges by using the normal...