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Teil 1: Unterschiede bei der Stabilitätsausnutzung

Der Eurocode EN 1993-1-1 bietet grundsätzlich zwei Verfahren für den Stabilitätsnachweis von Stäben an:

(1) basierend auf Abminderungsfaktoren (Knickkurven) und

(2) basierend auf äquivalenten (eigenformaffinen) geometrischen Imperfektionen.

In diesem Artikel wird untersucht, wie sich diese beiden Methoden in Bezug auf die endgültige Stabauslastung Im Vergleich verhalten. Der Einfachheit halber betrachten wir nur eine einfache zentrisch beanspruchte Druckstütze, die auf Biegeknicken versagt. Für Fall (1) wird Kapitel 6.3.1 verwendet, während für Fall (2) angenommen wird, dass die Imperfektionen die Form der zum ersten Eigenwert gehörenden Knickfigur annehmen, und das entsprechende Kapitel ist 5.3.2 (11).

Offensichtlich sollten diese zwei Standardverfahren die gleiche Ausnutzung für das gleiche Problem ergeben. Dies ist jedoch im Allgemeinen bei weitem nicht der Fall.

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Gewöhnlich zeigt traditionelle baustatische Software die Verformungen von Balken mit ihren Querschnitten auf der verformten Schwerachse. ConSteel 15 dagegen benutzt eine fortschrittliche Methode für Deformationsdarstellungen, die feiner und realistischer ist. Natürlich sind die numerischen Ergebnisse identisch, aber mit der verfeinerten Visualisierung kann das 3D-Verhalten der Balkenstruktur besser erkannt werden.

Comparison of chosen methods for estimation of critical lateral torsional buckling bending moment of web-tapered I-beams. In this article, the elastic critical bending moments of the web-tapered I-beams calculated by the analytical and numerical solutions developed last years by researchers involved in the topic were compared with own calculations carried out with available common tools. The main goal was to verify the accuracy and convergence of the results provided by different modern methods and different finite bar elements 1D with 7 degrees od freedom at the node (7DOF).

Click the button bellow to download and read the full article. (PL)

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D. Czepiżak, A. Machowiak: Comparison of chosen methods for estimation of critical lateral torsional buckling bending moment of web-tapered I-beams. Inżynieria i Budownictwo Nr 5–6/2021

Consteel 14 is a powerful analysis and design software for structural engineers. Watch our video how to get started with Consteel.

Contents

This article aims to cover the theoretical background of the shear field stiffness determination methods implemented in Consteel. Modeling with the shear field stiffness based method will also be compared with shell modeling of trapezoidal deckings in Consteel.

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Modeling of tapered elements

Stability calculation of tapered members is always a difficult problem despite its popularity in steel hall construction.

Generally in analysis software for the stability analysis a segmented but uniform beam element method is used where a member with I or H cross section and with variable web depth is divided into n segments and the depth of each segment is taken equal to the real depth measured at the middle of the segment. The lengths of the segments were taken equal, except at both ends where additional shorter segments are added in order the better approximate the real depth of the elements to be modeled. Such model captures correctly the in-plane displacements, but cannot consider accurately the additional torsion coming from the axial stresses due to warping in the flanges which are not parallel with the reference line in case of tapered elements.

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Introduction

As you may already know, you can check the max, min and min-max envelope diagrams for (first and second order) analysis results in Consteel. But you can also create your own envelope figures…

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Introduction

In case of a model with a lot of load cases (wind in different directions, with and without internal pressure, snow,seismic etc.), hundreds of load combinations can be generated acc. to EC but many of these combinations are irrelevant. Running an Analysis on all of the load combinations can take a lot of time, that could be saved, if the relevant load combinations are calculated only.

GATE

The main objective of the research paper is to present the technical and economical results obtained for standardized structures with small and medium spans. The obtained results can represent a starting point for designers as well as for investors, who intend to build single storey steel structures. According to the research, there have been identified a series of interrelated factors which may represent sources of savings in the optimization process. The authors highlight the work strategy in creating standardized structural systems that will improve product performances. The paper analyzes three standardized configurations including the following structural solutions: frame structures made of hot rolled beams and columns, thin-walled frame structures and structures using trusses and rectangular hollow sections columns. All configurations have been analyzed using Consteel 7.0 design software, for Bucharest region, loads evaluation being performed according to the current standards. Free height of the building varies between 4.00m and 6.00m, bay between
4.00m and 5.00m, and the span between 8.00m and 12.00m. The article presents the principle of the structural configurations and gives reference charts in order to estimate the steel consumption per square meter, aiming structural performance in what concerns price per square meter and execution time.

Click the button bellow to download and read the full article. (ROU)

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Zs Nagy, A Jurcut, A Pop, I Mois: Technical and economical performance of thin-walled steel structures vs. Hot rolled profiles, Tendințe actuale în Ingineria structurilor Metalice, Lucrările celei de-a Xiii-a conferințe naționale de Construcții metalice, București, 21-22 noiembrie 2013

Nowe trendy w normach: EUROKOD 3 – efektywne globalne projektowanie konstrukcji.

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Szalai J, Papp F. Nowe trendy w normach: EUROKOD 3 – efektywne globalne projektowanie konstrukcji. Inzynier Budownictwa, 81/2, pp. 39-43. 2011.