Problem of behaviour and ultimate strength of the centrically patch-loaded steel I-girders without longitudinal stiffeners and with largely spaced transverse stiffeners is analysed. The research is ...focused on two parameters - load length and initial geometrical imperfections of a girder web. This paper presents the experimental research, while the companion paper includes a numerical analysis of the problem.
The experimental campaign is described in detail. Results, comments and conclusions from seven tests are presented. The observed increase of the ultimate strength with the load length increase is not quantified due to the scatter of results which is typical for all previous experimental studies in this field. The scatter of results is a consequence of the intricate initial geometrical imperfections of the web which were measured on the most of the specimens. Following conclusions from the experimental research are used in the companion paper to develop reliable numerical models of the experimentally tested girders. It is necessary to model in detail the contact between load block and loaded flange, to account for the variation of contact pressure during the load application. The initial geometrical imperfections of the web in the load introduction zone have more significant influence on the development of lateral web deformation and thereof the ultimate strength, compared to the web imperfections adjacent to the unloaded flange.
Finally, based on the performed experimental research, the companion paper presents a detailed parametric numerical analysis of the problem and proposes a correction factor for the load length.
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•An experimental research on four I-girders subjected to patch loading is presented.•Increase of girder ultimate strength with load length increase is observed.•It was not possible to quantify this increase due to scatter of experimental results.•The main reason for the scatter of results is intricate geometrical web imperfections.•Based on the experimental research a numerical analysis is performed in the companion paper.
The research deals with structural response and ultimate strength of patch-loaded steel I-girders without longitudinal stiffeners and with largely spaced transverse stiffeners. Part-I of the ...research, i.e. experimental research is presented in the companion paper. Numerical analysis of load length influence on the ultimate strength of the girder is presented in the current paper.
Based on conclusions from the experimental research geometrically and materially nonlinear finite element models of experimentally tested girders were developed. Special attention is paid in modelling the contact between load block and loaded flange and in modelling the approximate geometrical imperfections of the web that best fit the experimentally measured imperfections. Detailed validation of numerical models is done by comparison of numerical and experimental results. Following data are compared: ultimate loads, deflections of loaded flange, vertical strains at measuring points on the web and lateral web deformations. Good agreement between numerical and experimental results is achieved.
Quantification of load length influence on ultimate strength as a main objective of the research is made through parametric numerical analysis. Numerical base containing 143 runs is created in which the load length and web thickness are varied. Other geometrical characteristics and material properties of girders, as well as initial geometrical imperfections of the web, are kept constant which could not be provided in the experimental study. By regression analysis of the results of parametric study a simple correction factor for load length is proposed. Accuracy of the proposed expression is proved through statistical analysis over concerned numerical base.
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•Geometrically and materially nonlinear finite element models of experimentally tested girders are developed.•Approximate web imperfections and contact between load block and loaded flange are simulated.•Good agreement between numerical and experimental results is achieved.•Numerical base containing 143 tests is created.•Simple empirical correction factor for load length is proposed.
K-joints of welded aluminium lattice structure made of circular hollow section (CHS) profiles are analysed. Aluminium alloy EN AW 6082 T6 was used.
The paper topic is determination of design ...resistance of K-joint in aluminium lattice structure. Change of mechanical properties of material in welding zones due to high temperatures is important characteristic of aluminium. Level and manner of influence of aluminium softening in zone of welded joint on design joint resistance have been analysed in paper.
Theoretical, experimental and numerical analysis by means of finite elements method (FEM) with 12 specimens of K-joint have been done. European Standard for aluminium structures EN 1999 does not define design resistance of joint in welded aluminium lattice structures. Therefore expressions from standard for steel structures were used. The aim of the paper was to investigate up to which level expressions from EN 1993-1-8 for design resistance of K-joints in welded steel lattice structure may be used for aluminium alloys structures, having in mind change of material properties in welded joints. After comparative analysis, correction and upgrade of expressions from steel structures standard have been proposed, in order to enable their implementation for determination of design resistance of K-joints in aluminium lattice structures.
•Aluminium is contemporary material with increasing application in lattice structures.•European standard for aluminium structures does not define calculation procedure for joints in welded lattice structures.•Change of aluminium mechanical properties in the vicinity of welds is important factor for K-joint resistance.•Design calculation of aluminium structures is based on design calculation methods for steel structures.•Design resistance of K-joint with CHS profiles might be determined by means of aluminium softening reduction factor.
Analysis of locally loaded steel plate girders Aleksić, Srđa; Rogač, Milivoje; Lučić, Duško
Journal of constructional steel research,
October 2013, 2013-10-00, Letnik:
89
Journal Article
Recenzirano
The paper deals with the problem of ultimate load capacity of thin-walled steel I-girders under the patch load which acts in the web plane of the girder. It considers the patch load type “a” ...according to EN1993-1-5. The analysed problem is very complex with the girder carrying capacity loss due to buckling of the web under the loaded flange. An experimental research of twelve plate steel girders subjected to patch loading is presented. The mathematical model for calculating ultimate load capacity of thin-walled steel I-girder under the patch load is proposed. Experimentally obtained ultimate loads and ultimate loads calculated by EN1993-1-5 are compared with those calculated by the proposed model. Experimental database consists of 52 tests from the experimental researches which were done at the Civil Engineering Faculty, University of Montenegro.
•An exp. research of steel plate girders subjected to patch loading is presented.•Ultimate load is reached due to buckling of the isolated web plate under the load.•The mathematical model for calculating ultimate load capacity is proposed.•The proposed model is stable and it provides a realistic prediction of ultimate load.•The EN1993-1-5 model shows signs of instability and underestimates ultimate load.
A numerical analysis of the flange impact on the critical load level of thin-walled I-girders subjected to patch load. The analysis is done by forming a 3D model in Abaqus software based on the ...finite element method, through variation of flange to web thickness ratio. 2D numerical models of girders web as isolated plate are also created. Matching of the 2D numerical results with results of existing analytical model, is the real basis for the expected accuracy of the 3D model.
This paper presents the bond stress – slip behavior of a newly developed grouted splice connection fabricated by glass fiber-reinforced polymer (GFRP). A total of twenty seven specimens were tested ...under increasing axial tension load. Results from the test specimens were adapted to model a bond stress – slip law to be compared with the requirements provided by design codes and provisions. The results show that by reducing mid-length diameter, higher bond strength and load capacity are generated in the tapered splice sleeves.
A numerical analysis of the flange impact on the critical load level of thin-walled l-girders subjected to patch load. The analysis is done by forming a 3D model in Abaqus software based on the ...finite element method, through variation of flange to web thickness ratio. 2D numerical models of girders web as isolated plate are also created. Consistence of 2D numerical and existing analytical results is the real basis for the expected accuracy of the 3D model.Original Abstract: U radu je prikazana numericka analiza utjecaja pojasnica na razinu kriticnog opterecenja tankostijenog l-nosaca opterecenog koncentriranim opterecenjem. Analiza je provedena formiranjem 3D modela u programskom paketu Abaqus na temelju metode konacnih elemenata, varirajuci odnos debljine pojasnica prema debljini hrpta. Podudaranje rezultata 2D numerickih modela hrpta nosaca kao izdvojene ploce s rezultatima postojeceg analitickog modela predstavlja realnu osnovu na kojoj se temelji ocekivana tocnost 3D modela.
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