László Dunai

László Dunai
Budapest University of Technology and Economics · Department of Structural Engineering

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129
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Publications

Publications (129)
Article
There is currently no reliable and simple design method available in international literature for the determination of the patch loading resistance of slender plate girders having multiple longitudinal stiffeners. Previous investigations focused mainly on girders having one longitudinal stiffener, which is not the common case for box‐girder bridges...
Article
Knee joints in steel portal frames with bolted connections typically present stiffeners to ensure proper load bearing resistance. Executing the same stiffeners with a reduced height allows for cost saving but must be paid off by considering its effects in the design verification of the joint. The gap of the partial stiffener has a height of 10% to...
Article
Current standards and specifications do not provide specific design methods to determine the lateral-torsional buckling (LTB) strength of girders with trapezoidally corrugated web. In the international literature there are some previous investigations available focusing on the LTB strength of corrugated web girders. Based on numerical calculations...
Article
Full-text available
Before the recent reconstruction, significant corrosion damages were observed on the deck system of the ~170- year-old Sz´echenyi Chain Bridge. Therefore, an advanced reliability analysis-based study is executed to assess the risk of failure of the structure in its situation until the refurbishment starts. The current paper has the aim to introduce...
Article
Safety and security of critical infrastructure networks is one of today’s top priorities, as they are getting increasingly complex and interdependent. Thus, their potential failure due to unforeseen and extreme events may result in excessive direct and indirect losses. Recently, focus has shifted from protection to resilience, i.e. the ability of a...
Article
In this paper the lateral-torsional buckling (LTB) behavior of steel trapezoidally corrugated web girders is studied by advanced nonlinear finite element (FE) analysis in order to develop new computer-based design method for the determination of the LTB strength of such innovative members subjected to pure bending. Due to the low number of previous...
Article
The Széchenyi Chain Bridge is a 170-year-old historical structure located in the downtown of Budapest. The superstructure of the bridge was reconstructed several times in its history and currently the renewal process of the bridge is under consideration. According to the current plans main girders, chain elements and cross-girders will remain the o...
Article
Steel I-girders with slender web are commonly used in the engineering practice. Previous research results proved that the current bending and shear interaction (M-V) check of the EN1993-1-5 does not always provide safe side resistance. The current research work focuses on the analysis of the M-V interaction behavior of longitudinally unstiffened an...
Conference Paper
Current standards and specifications do not provide design methods to determine the lateral-torsional buckling (LTB) strength of girders with trapezoidally corrugated web. In the international literature there is only a limited number of previous investigations available focusing on the LTB strength of corrugated web girders. Based on numerical cal...
Article
de Dedicated to Univ.‐Prof. Dr.‐Ing. habil. Frank Werner on his 70th birthday Zusammenarbeit zwischen Weimar und Budapest bei der rechnergestützten Modellierung von Stahl‐ und Verbundkonstruktionen Der Beitrag gibt einen Überblick über die langjährige Zusammenarbeit zwischen der Bauhaus‐Universität Weimar und der Budapester Universität für Technik...
Conference Paper
Full-text available
Steel corrugated web girders are increasingly used in buildings, industrial halls and bridges due to their well-known advantages. Numerous researchers highlighted and studied the advantages and favorable properties of the trapezoidally corrugated web girders in the past. However, there are only a limited number of available design proposals for the...
Article
Bridges with box cross-sections are usually stiffened by the combination of longitudinal and transverse stiffeners. The longitudinal stiffeners are loaded by axial force, and the transverse stiffeners should give sufficient support to them. The design of transverse stiffeners without direct loading can be done by the verification of the minimum sti...
Article
This article gives an overview on the rehabilitation of historical Danube bridges, which are located in the UNESCO World Heritage part of Budapest: Széchenyi chain bridge, Margaret bridge, Liberty bridge, and Elizabeth bridge. The bridges are briefly introduced and then their rehabilitations are presented. The special aspects of the design of recon...
Article
Full-text available
Previous studies on stressed skin effect of industrial steel buildings showed discrepancies between the ECCS formulae and experimental results. To clarify the discrepancies full-scale experimental test program was planned and executed by the Budapest University of Technology and Economics, Department of Structural Engineering. The aims of the full-...
Conference Paper
Steel girders with trapezoidally corrugated web are widely used structural members in the civil engineering praxis due to their favorable behavior. The stress distributions and the bending-shear interaction of trapezoidally corrugated web girders have been already investigated in the case of compact flanges. Furthermore, the flange buckling behavio...
Article
Steel I-girders with longitudinally stiffened webs are commonly used in the civil engineering praxis, especially in bridges. These structures have usually longitudinal stiffeners on the webs, therefore the determination of the load carrying capacity of girders with longitudinally stiffened webs under the combined loading situation (interaction of b...
Article
Previous studies proved that the patch loading resistance model of the EN1993-1-5 can lead to significant underestimation of the patch loading resistance in case of longitudinally stiffened girders. Recently there are several research activities to improve the design method. In the current study experimental research program is executed on 8 large...
Article
A new direction of development in the field of light-gauge building systems is when the load bearing elements made of cold-formed steel (CFS) sections are encased in an ultra-lightweight material. This material, apart from heat insulation and fire protection effects, can provide bracing effect to the CFS elements, too, therefore can increase the re...
Article
The superstructure of the historical Széchenyi chain bridge in Budapest was reconstructed several times in the history and currently the renewal of the bridge is under design. The independent static check and expertizing tasks of the renewal process were completed by the Budapest University of Technology and Economics Department of Structural Engin...
Article
Civil engineering structures are subjected to enormous cyclic forces during a seismic event. Designing structures with dissipative zones provides an efficient solution to withstand these seismic forces. The zones, which dissipate energy through plastification, can be designated parts of the structural skeleton, or special, sacrificable elements tha...
Article
Girders with trapezoidally corrugated web are widely used structural elements in the civil engineering praxis due to their numerous advantages. However, there is a relatively small number of previous investigations focusing on the determination of the flange buckling resistance of the corrugated web girders. Previous experimental and numerical inve...
Article
Previous research has shown that the residual stresses in high-strength steel (HSS) members can be smaller than those in normal-strength steel structures. To investigate the residual stress distribution in HSS structures, a complex experimental and numerical research programme was carried out on welded square box sections at the Budapest University...
Article
Girders with trapezoidally corrugated web are widely used structural elements in the civil engineering praxis due to their numerous advantages. Despite, there are a relatively small number of previous investigations focusing on the determination of the bending moment resistance and the flange buckling behavior. Previous experimental and numerical i...
Article
A novel thin-walled structural system is under development which aims to utilise the beneficial effect of continuous bracing achieved by encasing CFS elements in ultra-lightweight-concrete. This paper deals with the experimental analysis of column-end joints. Altogether six types of end connection and four cross-sections were tested by 18 unbraced...
Article
Application of the corrugated web girders has been widely spread due to their numerous advantages in the field of bridges and buildings in the civil engineering praxis. This girder type has a special stress distribution and buckling behavior compared to conventional steel I-girders. Despite, there are a relative small number of previous investigati...
Article
Longitudinally unstiffened steel I-girders are commonly used structural elements in the engineering practice. Previous research results proved that the current design method of the EN1993-1-5 EN 1993-1-5 (2005) for M-V interaction check is not always on the safe side for longitudinally stiffened girders, however a systematic review of the M-V inter...
Article
Steel corrugated webs are likely used in the field of bridges in the last few decades due to their numerous advantages. The most favorable layout is the hybrid girder with upper and lower reinforced concrete slabs and with steel corrugated webs. During incremental launching – without concrete flanges – the steel girder can be subjected by the combi...
Article
Full-text available
The new Hárosi Danube bridge on the M0 highway around Budapest has been designed and erected between 2010-2012. The superstructure of the bridge is a continuous steel box girder with 3 spans (3 x 108.5 m). The independent static check in the final stage and during the launching phases are made by the BME Department of Structural Engineering. The cu...
Article
Full-text available
In frame of the tramway network development in Budapest a new tramway line has been established on the south part of Budapest, which crosses the Danube on the Rákóczi-bridge. The bridge superstructure is a continuous double-cell steel box girder having 6 spans with the largest span of 98.52 m. The bridge was originally designed to carry four traffi...
Conference Paper
Full-text available
Steel girders with trapezoidally corrugated webs are increasingly used in the field of bridges, especially in case of hybrid and composite bridges. During incremental launching of the bridge the main girders are subjected to bending moment (M) with accompanying shear (V) and transverse forces (F) in the same cross-section, which can result in a cou...
Article
Girders with corrugated steel web is likely used in bridges as well as in building structures due to its numerous favourable properties. It is known from previous investigations that due to the web corrugation the normal and shear stress distribution in the flange and web plates of the corrugated web girders are different from the stress distributi...
Article
In the field of structural engineering the design of cost efficient structures is highly important. This led to the development of cold-formed steel structures (CFS). An advanced CFS structure is introduced in this paper, which uses a special type of polystyrene aggregate concrete (PAC) as bracing material. This material has beneficial insulating a...
Article
In the field of structural engineering the design of cost efficient structures is highly important. This led to the development of cold-formed steel structures (CFS). An advanced CFS structure is introduced in this paper, which uses a special type of polystyrene aggregate concrete (PAC) as bracing material. This material has beneficial insulating a...
Article
The paper presents a study on the buckling of corroded equal-leg angle-section members. The remaining load-bearing capacity and the prospective behaviour modes are analysed by experimental and numerical research. The diversity of the corrosion is taken into consideration in the analysis; the corrosion is modelled by thickness reduction. Compressive...
Article
Full-text available
During the last decades orthotropic steel decks have become a widely used component of steel bridges, however high numbers of fatigue cracks have been recently detected in these structure types. It is well known, that the orthotropic decks are sensitive to fatigue damage, therefore safe fatigue design is important for the safety assessment of bridg...
Article
This paper is on the numerical analysis of concrete filled Buckling Restrained Braces (BRBs), which are typically used as diagonal bracing members of steel braced frames designed for dissipative behavior and lateral load resistance under seismic action. BRBs are typically composed of a slender steel core which is continuously supported by a concret...
Article
Steel girders with corrugated webs are increasingly used in the field of bridges, especially in case of composite bridges. During launching of a bridge structure the girder can be subjected by the combination of bending moment (M), shear (V) and transverse forces (F) which result in a complex stress field in the girder and in an interacting stabili...
Article
Full-text available
The paper presents the details and results of an experimental study on bolted end-plate joints of industrial type steel building frames. The investigated joints are commonly used in Lindab-Astron industrial buildings and are optimized for manufacturing, erection and durability. The aim of the research was to provide an experimental background for t...
Article
Full-text available
A cikk fejes csapok hegesztett kötéseinek nyírási teherbírási és fáradási viselkedésének laboratóriumi vizsgálati eredményeit mutatja be. Az együttdolgozást biztosító nyírt fejes csap mind magasépítési öszvérszerkezetekben az acél főtartó és vasbeton födémszerkezetek kapcsolataiban, mind öszvérszer-kezetű hidak főtartóinak és vasbeton pályalemezéne...
Article
During launching of a bridge structure large bending moment, shear and transverse forces can often occur at the same time in the same cross section which can result in governing situations for the design. In case of these structures the interacting stability behaviour should be taken into consideration. Bridge structures have usually longitudinal s...
Article
If steel structures are subjected to the combination of bending, shear and patch loading, the interacting stability behaviour in the design should be taken into consideration. The combined loading situation can often occur in case of bridge girders during launching, therefore the determination of the load carrying capacity under the combined loadin...
Article
Corrugated steel plate has been increasingly used in the last 20 years for beam webs in hybrid and composite bridges. Girders with corrugated webs have many advantages over traditional structures with flat webs, but due to the new structural layout, there are still many design questions that need to be solved. In cases with girders with trapezoidal...
Article
In this paper, the behavior of deep trapezoidal sheeting with perforated webs is studied. The analyzed panel has longitudinal stiffeners both in the webs and flanges, which improves the load-bearing capacity but makes the behavior more complicated. The considered panel is produced with and without web perforations. When web perforation is applied,...
Article
Full-text available
The EN 15129 standard specifies the requirements for anti-seismic devices in Europe. The nonlinear displacement dependent device (NLD) group collects solutions that typically use the nonlinear properties of their material to dissipate energy and mitigate seismic damage. EN 15129 controls the cyclic hardening behavior of NLDs with a set of stringent...
Article
Full-text available
The development of a steel material model in order to follow the cyclic plastic behaviour is essential in seismic design. The authors present an improved Chaboche model for the cyclic mechanical behaviour of structural steel. The model is based on the combination of nonlinear kinematic and multi-linear isotropic hardening with a parameter refreshin...
Article
Full-text available
The paper is on the behaviour of corroded angle section members under centric compression. The structural elements, with different cross-sections and slenderness, are studied by finite element analysis. The joint effects of various corrosion parameters are studied. The behaviour modes are determined in the function of the parameters of the corrosio...
Chapter
The main aim of the current research is to develop an efficient classification system for cross-section of structural members under cyclic loading. This classification system has to take into consideration the complex cyclic stability phenomena of the different elements of the profile in a simpler way, similarly to the cross-section classification...
Chapter
Current study intends to analyse the behaviour of the corroded angle-section members under eccentric compression. The arrangement and volume of the corrosion are various on the elements. Two different end supports are applied in the tests and the effect of them on the behaviour and on the resistance are studied. The applied supports are bolted conn...
Chapter
In case of steel beam-to-column joints the bending resistance is significantly influenced by the shear strength of the web panel. The compression side resistance of the joint is limited by the web panel in shear component and in case of special geometries it can give a relatively strong limitation for the bending resistance of the whole joint. In t...
Article
The corrugated steel plate is a widely used structural element in many fields of application because of its numerous favorable properties. Due to the web corrugation the normal and shear stress distribution in the flange and web plates are different from the stress distribution of the conventional I-girders under in-plane bending and shear. The foc...
Article
Due to its advantages corrugated steel plates are widely used in various applications. Engineers realized a potential application field in bridges, especially in composite bridges. When such a bridge is incrementally launched, the girder is subjected to combined action of bending moment, shear and transverse forces, resulting in a complex stress fi...
Article
The study deals with the mechanical behaviour of laterally loaded structural glass laminated with polyvinyl butyral (PVB) interlayer. To evaluate the influence of the mechanical behaviour of PVB in structural glass plates, a finite element model was developed. The numerical model was verified on the basis of the results from the literature and by o...
Article
The study deals with the mechanical behaviour of laterally loaded structural glass laminated with polyvinyl butyral (PVB) interlayer. To evaluate the influence of the mechanical behaviour of PVB in structural glass plates, a finite element model was developed. The numerical model was verified on the basis of the results from the literature and by o...
Article
Full-text available
The research activity presented in this paper focuses on the effect of sliding clips and intermediate elements (bridge system) on the secondary load-bearing beams (Z-purlins) in standing seam roofs. The main aim is to determine the lateral stiffness of the system to be used in the stability checking of Z-purlins. The representing element of the roo...
Article
Full-text available
The aim of this work is to study the effect of corrosion on the buckling behaviour and resistance of corroded steel angle section members. The influences of the corrosion location and the loss of cross-section are studied by experimental investigations, where the corrosion is modelled by artificial thickness reduction. Compressive buckling tests ar...
Article
In this paper the use of mixed time integration is proposed to increase the efficiency of welding simulation. A technique similar to the one commonly used in sheet metal forming is applied to the welding of steel plates. The welding procedure can be divided into two very distinguishable parts with significantly different characteristics. The first...
Article
The corrugated steel plate is a widely used structural element in many fields because of its many favourable properties. This structural layout has spread in the field of bridges, too, especially for steel and composite bridges. Against of the numerous applications there are no standard design formulas for the patch loading resistance of girders wi...
Article
The subject of the ongoing research work is to analyze the composite action of the structural elements of composite slabs with profiled steel decking by experimental and numerical studies. The mechanical and frictional interlocks result in a complex behaviour and failure under horizontal shear action. This is why the design characteristics can be d...
Article
2010-ben készült el a nemzetközi viszonylatban is különlegesnek számító, szolnoki gyalogos-kerékpáros Tisza-híd: a Tiszavirág híd, amelynek átfogó statikai és dinamikai próbaterhelési vizsgálatait a BME Hidak és Szerkezetek Tanszék végezte el. Tekintettel a fesztávra, a speciális ív- és pályaszerkezetre, függesztő rudakra, a híd karcsúságára, már a...
Article
Full-text available
The subject of the ongoing research work is to analyze the composite action of the structural elements of composite floors by experimental and numerical studies with a special focus on the rolled embossments on the steel surface. The mechanical and frictional interlocks result in a complex behaviour and failure under horizontal shear This is why th...
Article
The corrugated steel plate is a widely used structural element in many fields of application because of its favourable properties and has been applied since the 1920s. For the last 20 years it has been increasingly used in the web of steel and composite bridges. When such a bridge is incrementally launched, buckling of the thin steel web may occur....
Article
Full-text available
In this paper results of an ongoing research on cold-formed C-section members are presented. The research aims the development of design methods for structural arrangements directly not covered by the standard, based on laboratory tests and numerical modelling. In the paper laboratory tests on C-section compression members are presented: arrangemen...
Article
Full-text available
The corrugated steel plate has been increasingly used as web of steel and composite bridges. When such a bridge is incrementally launched, the web panels are often subjected to combined shear and patch loading. There are only a few investigations available in the literature which are dealing with this interaction type, therefore the current researc...
Article
This paper presents an experimental study of a newly developed composite floor system, built up from thin-walled C-profiles and upper concrete deck. Trapezoidal sheeting provides the formwork and the fastening of the sheet transmits the shear forces between the C-profiles and the deck. The modified formation of the standard self-drilling screw in t...
Article
The paper presents the details and results of an experimental study on bolted end-plate joints of industrial type steel buildings. The investigated types of joint are common used by Lindab-ASTRON-Butler Co. and these are optimized from the manufacturing, erection and durability point of view. The aim of the research was to provide with an experimen...
Article
Full-text available
The state-of-the-art geodetic and remote sensing techniques can prove their potential through particular engineering applications. Besides the traditional surveying terrestrial laserscanning broadens its application. field in. civil engineering projects. The Department of Photogrammetry and Geoinformatics has long experience in the measurement meth...
Article
This paper deals with the investigation of laserscanning in load test measurements of the Megyeri bridge. It discusses the procedure of the simultaneous measurement of two scanners and the processing of the laserscanned point cloud. The (graphical and numerical) evaluation of results is extended by recommendations for further application of lasersc...
Chapter
The paper deals with the numerical fatigue analysis of the steel orthotropic bridge decks. The main focus is on the welded connection of the longitudinal rib and the deckplate. Advanced numerical model is developed to predict the fatigue-life of this structural detail on the basis of hot-spot-stresses, using the recommendations of the IIW and Euroc...
Chapter
An extended experimental and numerical research program is completed on plate girders fabricated by automatic single sided fillet welds. The imperfections of the test specimens are measured and characterized. Load-bearing tests are carried out to study stability behaviour modes: local and shear buckling, web crippling, lateral torsional buckling. A...
Article
In this paper experimental and standard-based analyses on C-profiled cold-formed compression members under supporting conditions and arrangements not fully covered by standard calculation methods are presented. The specimens used in the two cases are made of a single asymmetrical C-section. The third type of specimen consists of two C-sections stic...
Article
The subject of this paper is the analysis of end-plate joints under cyclic and monotonic loading conditions by experimental and analytical studies. The experimental programs are performed on bolted end-plate type joints of composite members under cyclic loading conditions with the purpose to study the seismic response of the considered connection t...
Article
Full-text available
Terrestrial laserscanning broadens its application area in the civil engineering industry. This paper discusses the potential of the technology through the example of the deformation measurement of a new Hungarian bridge on the Danube during its load testing procedure. The paper discusses the complex procedure from the field measurement through pri...