1 Steel Structures

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					 Steel Structures

                                                                                                                              B. Froschmeier
                                                                                                         B. Braun

                                                                                                                                                        A. Zizza
 Thin-walled Steel-Profiles susceptible to lateral Buckling
Thin-walled steel-profiles susceptible to lateral        (FEM) were executed. With the aid of these
buckling are frequently used in bridge design,           results several design concepts were assessed.
e.g. tied-arch bridges in box section shape. The         Additional imperfections for the calculation with
application of high strength steel and the tenden-       2nd order theory were defined. This project was
cy towards lightweight structures leads to the use       executed in cooperation with the Universität
of such thin-walled slender steel-profiles. These        Dortmund, where open thin walled sections were
members are subjected to two different types of          studied. Part of the work has been realized by Dr.
stability failure, local plate buckling and global       Luka Pavlovics, Ljubliana.
                                                                                                                    Tied-arch bridge
buckling. The design concepts for the determina-
tion of the load bearing capacity of these profiles
given in the European codes are deficient, becau-
se the calculated load bearing capacity in compa-        Acknowledgement is made to the German
rison to the experimentally determined can be            Commission for Steel construction (DASt) for the
safe-sided as well as insecure. In the frame of          funding of the research project AiF 15025 within a
this project, the influence of the interaction effect    research programme of the Federal Ministry of
between the two different failure modes is resear-       Economics and Technology (BMWi).
ched. Based on tests of welded and cold formed
columns under compression and bending load,                                                                         FE-simulation of the compressed RHS
                                                          Contact person: Dipl.-Ing. Bernadette Froschmeier
numerical studies using the finite element method                                                                   (shown for a half cross-section)

 Combined Steel Walls
Frequently with the building of quay constructions       load-carrying capacity takes place and so the
combined steel walls, consisting of H- shaped king       former load and/or safety level can easily be
piles and Z- shaped infill sheet piles, are used to      achieved. In the recent project P813 “Develop-
bridge over large spans. The calculation of              ment of efficient dimensioning for the king piles of
examples showed that after introduction of the           combined steel walls” the support will be quanti-
new stability verification according to EN 1993-1-1      fied by experimental and numerical investigations,
problems arise for the king piles in terms of oversi-    efficient design rules will be developed and publis-
zing compared with constructions, which are in           hed for the practical use. The research is realized
use today. In order to guarantee an efficient stabili-   in cooperation with Prof. Dr. Grabe, the chair of
ty calculation, new basics for the application of the    Geotechnics, TU Hamburg-Harburg.
European rules have to be created.                       Acknowledgement is made to the German
The aim is to allow the consideration of the             “Forschungsvereinigung Stahlanwendung e.V.
support of the king piles by the infill sheet piles on   (FOSTA)” for the funding of the research project
one hand and the embedment in the ground on              P775/13/2007 and also the new project P813, that
the other hand in design. Investigations in the          is funded within a research programme of the
context of the FOSTA short study P775 showed             Federal Ministry of Economics and Technology
that with the calculation of small (rotational)          (BMWi).
embedding values already a large increase of the          Contact person: Dipl.-Ing. Bernadette Froschmeier

 Buckling Interaction of slender Plates
Modern steel constructions are characterized by          beams with longitudinal stiffeners and interaction
slender structures and the optimization of their         of bending and shear loading. The aim of this
manufacture. The steel plates then tend to buckle        project is a description of the load bearing behavi-
due to the fact that they often achieve high             or considering the torsional rigidity of the longitudi-
slenderness.                                             nal stiffeners used nowadays. This leads to
The European RFCS project COMBRI and                     complex multiaxial stress state for which an
COMBRI+ concentrated on experimental and                 adapted equation has to be developed. A contribu-
numerical investigations on combinations of shear        tion on general questions regarding the numerical
                                                                                                                    Bridge erection by incremental launching
and patch loading. The results have been worked          verification of complex structures with FE will be
out to a manual which can be downloaded from the         made.
institute’s homepage. In the context of a national
AiF-DASt-project (together with RWTH Aachen, Acknowledgement is made to the German
TUM Munich) in order to facilitate the appliance of Research Foundation (DFG) for the funding of the
EN 1993-1-5 a guide has been developed additio- current research project.
In the frame of the current DFG-project and in
collaboration with the University of Ljubliana            Contact persons: Dipl.-Ing. Benjamin Braun
experimental investigations will be conducted for                          Dipl.-Ing. Antonio Zizza                 Bending- and shear test

               Institute of Structural Design
               Steel-, Timber- and
               Composite Structures
               Prof. Dr.-Ing. Ulrike Kuhlmann

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