Die Wirtschaftlichkeit von Stahlbauten hängt insbesondere von der zuverlässigen Bestimmung der erreichbaren Dauerhaftigkeit von der Herstellung über die gesamte Nutzungszeit bis zum Ende der Lebensdauer ab. Insbesondere stellt sich im Rahmen von Sanierungs- und Reparaturvorhaben häufig die Frage nach der Schweißeignung von Stahl- und Eisenwerkstoffen, deren Erzeugung vor Mitte des 20. Jahrhunderts liegt und in vielen Fällen bis ins 19. Jahrhundert zurück reicht. Im Rahmen eines öffentlich geförderten Forschungsvorhabens sollte daher geklärt werden, wie sich die Restnutzungsdauer von reparaturgeschweißten Altstahlkonstruktionen unter zyklischer Beanspruchung verändert. Die vorliegenden Untersuchungsergebnisse lassen die Schlussfolgerung zu, dass bei vorhandener und auch eingeschränkter Schweißeignung eines Altstahles, die Restnutzungsdauer einer Konstruktion durch eine ordnungsgemäße schweißtechnische Verarbeitung nicht signifikant verändert wird, so lange diese frei von Kerben ist.

Useful lifetime of welded historic steel constructions under fatigue loading.
The economy of steel constructions depends in particular on the reliable determination of the attainable persistence over the entire period by making up to the end of life. In the context of renovation and repair projects, the weldability of steel and iron materials, which were made before the middle of the 20th century and in many cases also in the 19th century, has often to be clarified. In the context of a publicly-funded research project, it should be examined how to change the remaining utilization time of the repair welded old steel structures under cyclic loading. The results allow for the conclusion that for an old steel with a proper and also limited weldability, the remaining useful life of a construction is not significantly changed by a proper weldment, as long as it is free of notches.

In dem hier vorgestellten Forschungsprojekt wurden durch die TU Dortmund, die MPA Darmstadt und das Institut für Korrosionsschutz Dresden GmbH der wissenschaftliche und technische Nachweis eines sicheren Einsatzes der Feuerverzinkung im Stahl- und Verbundbrückenbau erbracht. Die Verwendung der Feuerverzinkung ermöglicht einen langlebigen, wartungsfreien und robusten Korrosionsschutz und bietet ökologische und ökonomische Vorteile gegenüber den aktuell eingesetzten Korrosionsschutzsystemen. Der Einsatz im Brückenbau mit zyklischen Belastungen war bislang - aufgrund fehlender wissenschaftlicher Untersuchungen zum Ermüdungsverhalten feuerverzinkten Stahls - nicht möglich. Die Ergebnisse dieses Forschungsprojekts ermöglichen den Nachweis des feuerverzinkten Stahls gegen Werkstoffermüdung nach EC 3-1-9 und weisen den sicheren Einsatz der Feuerverzinkung als Korrosionsschutzsystem nach.

Hot-dip galvanizing in bridge construction - Part 1: Using hot-dip galvanized mild steel for cyclic loaded structures.
In the here presented research project the scientific and technical evidence for the safe use of hot-dip galvanizing for steel and composite bridges were provided by TU Dortmund, MPA Darmstadt and Institut für Korrosionsschutz Dresden GmbH. The use of hot dip galvanizing offers a durable, maintenance-free and robust corrosion protection and provides environmental and economic advantages over the corrosion protection systems currently in use. The use in bridge construction with cyclic loading was previously not possible - due to a lack of scientific studies on the fatigue behavior of hot-dip galvanized steel. The results of this research allow the proof of hot-dip galvanized steel against fatigue according to EC 3-1-9 and demonstrate the safe use of hot dip galvanizing as corrosion protection system.

Der Einfluß der maßgebenden Parameter auf die Kaltrißgefahr bei Baustählen wird diskutiert und größenordnungsmäßig angegeben. Anschließend werden die Konzepte von DIN 18 800 Teil 1, DVS 1703 und BS 5135 zur Vermeidung von Kaltrissen hinsichtlich der maßgebenden Parameter überprüft und miteinander verglichen. Mit der Kenntnis des Einflusses der hier detailliert besprochenen Parameter auf die Kaltrißgefahr dürfte keine Schwierigkeit mehr bestehen, wenn erforderlich, von der 2-Formel abzuweichen.

Better and simpler possibilities of structural optimization due to increasing computational power but also for reasons of environmental sustainability, the use of materials and their reusability lead to greater acceptance towards more advanced numerically intensive, so-called ‘design by analysis’ methods like geometrically and materially non-linear analyses with imperfections (GMNIA). The general choice of imperfections and their combination in such models, especially for slender cross sections of intermediate length prone to an interaction between a global and local plate buckling, is crucial in terms of the reached load-bearing capacity. Annex C of EN 1993-1-5:2010 makes use of the ‘70 %-rule’ for the combination of imperfection modes and amplitudes. This rule postulates that two GMNIA calculations should be conducted when local and global interactive buckling may be dominant; one with 100 % + 70 % of the maximum specified amplitude in either case. In addition, extended information is provided on the choice and combination of imperfections in the newly introduced and currently available draft of the prEN 1993-1-14:2020 (design assisted by finite element analysis). Although information is provided on how the local and global imperfections should be combined, it is not stated when it is relevant to consider those. Based on conducted GMNIA simulations on SHS/RHS (square and rectangular hollow sections) and I-shaped sections, this article presents general decision support on the choice of equivalent imperfections. On the basis of numerical analysis, the developed flow chart and design routine allow for the decision whether the consideration of the interaction of local and global imperfections is required or not.

Extended keynote paper of Eurosteel 2021
This paper provides an overview of recent work regarding the revision of Eurocode 3 on the European level. Selected scientific and technical issues are described and there is a summary of the activities executed within European Standardization Committee CEN/TC250/SC3 “Design of Steel Structures” chaired by Prof. Dr.-Ing. Ulrike Kuhlmann. This includes the description of current normative developments for the 2nd Generation of Eurocodes, which aim at evolution through improvements and harmonization of the existing codes. In addition, a technical review of selected rules is given for several issues, which support the code revision and reflect well the recent tendencies in steel structures.

This paper discusses an innovative approach to the design of planar steel frames composed of prismatic and/or non-prismatic members. The method evaluates the member stability limit states using an inelastic eigenvalue buckling analysis configured with column, beam and beam-column inelastic stiffness reduction factors derived from the ANSI/AISC 360-16 Specification. The resulting procedure provides a relatively rigorous evaluation of all member strength limits accounting for moment and axial force variations along the member lengths, non-prismatic geometry effects, general out-of-plane bracing conditions and beneficial end restraint from less-critical adjacent, unbraced segments and/or from end conditions. The approach uses a geometric non-linear pre-buckling analysis based on the AISC direct analysis method to estimate the in-plane internal forces. Given these forces, an eigenvalue buckling solution is conducted to evaluate the overall member stability. Other limit states are addressed through cross-section strength checks using the internal forces determined from the geometric non-linear load-displacement analysis. Calculations using this approach are compared with results from recent experimental tests.

Kurita-Albrecht Best Scientific Paper Award - Steel at 12th Japan German Bridge Symposium, September 2018 in Munich
The temperature dependence of the mechanical behaviour of high damping rubber bearings (HDRBs) was investigated by way of cyclic loading tests at different ambient temperatures. As the number of loading cycles increased, so the difference between the ambient and internal temperatures of HDRBs increased due to self-heating, especially in subzero environments. It was found that the mechanical behaviour of HDRBs is governed by their internal temperatures, not by the ambient temperatures. A simple method for estimating the internal temperature is proposed. Previous cyclic loading tests results at different ambient temperatures have been re-examined based on the internal temperatures obtained from the proposed internal temperature estimation method. The temperature dependence of HDRBs is summarized in terms of the internal temperatures. The conventional temperature dependence based on the ambient temperature may underestimate the seismic response of bridges with HDRBs, especially for subzero environments.

Dedicated to Prof. Dr. Eng. Akimitsu Kurita on his 70th birthday, in honour of his scientific achievements, guidance and the education of his students.
Fire safety in bridge design is not as developed as fire safety in building design, even though a bridge failure can cause significant economic damage impacting on an area. This paper addresses an unanswered question with regard to fire safety, i.e. the capability to identify the governing failure mode of a bridge subjected to severe fire loading and ranking the regions of greatest fire exposure risk. Hence, this proposed methodology is also expected to support forensic work identifying the failure mode where a bridge has failed due to a severe fire, as will be shown using the 9-Mile Road Overpass collapse as an example. In an effort to mitigate fire damage, the fire protection panel (FFP) is introduced, which is part of a sacrificial structure shielding the bridge superstructure from exposure to fire from underneath.

The intention of this study is to investigate how vehicles on highway bridges affect the seismic responses of the bridges under strong ground motions. Most highway bridge design codes do not consider the live load in the seismic design of highway bridges because of the low probability of the two events of the critical live load and an earthquake occurring at the same time. As a result, little attention has been paid to the influence of vehicle loads on the seismic responses of highway bridges. However, considering the high probability of traffic jams on urban roads, it is preferable to examine and clarify the dynamic interaction effect of vehicles on road bridges while subjected to seismic loads. In this study, the vehicle-bridge-ground motion interactions are realized by combining ABAQUS and MATLAB. ABAQUS provides a GUI environment to establish the numerical bridge model and apply the seismic forces, while MATLAB provides a platform to control the iterations in both time and force increments. As a preliminary study, a simplified 3D pier-beam bridge model loaded with multiple vehicles with two degrees of freedom moving at a constant speed has been considered. When subjected to identical, strong seismic loadings, it was observed that the transverse accelerations of the bridge with moving vehicles are smaller than those without moving vehicles. Further, permanent deformation occurs after earthquakes because of yielding at the bottom of the pier; it was observed that the permanent deformations of the bridge with moving vehicles tend to be smaller than those without moving vehicles.

The 2010 AISC Specification for Structural Steel Buildings (AISC 360-10) forms the basis for the 14th edition of the AISC Steel Construction Manual. Both publications reflect changes in connection design requirements and practices. This paper summarizes the most relevant changes in connection design requirements and practices made in these latest versions of these documents.

Keine Kurzfassung verfügbar.

BVMB fordert bedarfsgerechte Finanzierung
Sicherheit am Bau: “Du hast nur 1 Leben!”
“Dem Handwerk einen Bärendienst erwiesen”

BVMB: Warum nicht in der Hand des Bundes?
Nur Meck-Pomm schwächelt im Supersommer
“Warum keine volle Nachrüstförderung?”

Enge Kooperation mit Bundestagsausschuss
Leichter Anstieg bei der Absolventenzahl
Fertighäuser legen am Markt weiter zu

Breite Zustimmung in der Bauwirtschaft
100-Tage-Bilanz der Bundesregierung kritisiert
Chance für eine sichere Bauwirtschaft?

Bau-Mittelstand bietet Unterstützung an
60 Mio. Euro Schaden durch Diebstahl am Bau
LKW-Maut erhöht die Baupreise

Steinbrecher strikt gegen Brückenteilzeit
Leichter Umsatzrückgang im ersten Quartal
“ÖPP schadet Mittelstand und Steuerzahler”

BVMB legt DB AG Lösungsansätze vor
Bauindustrie kritisiert Haushaltskürzungen
Ingenieurbüros klagen über Nachwuchsmangel

Steinbrecher warnt Merkel vor den Folgen
Tarifverträge am Bau allgemeinverbindlich
Am Ende bleiben im Schnitt 2, 6% der Forderungen

Keine Kurzfassung verfügbar.

Gemeinsame Vorgehensweise unerlässlich
“Bau-Mittelständler leiden unter Illegalität”
Deponieknappheit als Baupreistreiber

BVMB: Weg mit dem Vorschriften-Dschungel!
Massiver Gegenwind gegen “Staugebühr”
“Bauunternehmen tragen keine Schuld!”

Treffen des “who-is who” im Bau-Mittelstand
Kooperation statt Konfrontation
Ausgesprochen positive Herbstbilanz am Bau

BVMB sieht keinen zusätzlichen Bedarf
BG BAU fordert zu Präventionsmaßnahmen auf
Kritik an geplanter neuer EU-Entsenderichtlinie

Unzulässigkeit von Direktvergaben der DB AG angedeutet
Bauwirtschaft: Orderplus im zweiten Halbjahr
Über 1.000 Eisenbahnbrücken abbruchreif