Steel Design at the Serviceability Limit State
Serviceability design of a steel cantilever rack in RFEM 6 with the Steel Design add-on, from the normative basis to optimized cross sections. The session starts with what EN 1990 and EN 1993 actually require — limits agreed with the client and three action combinations — and then sets up every input the deflection checks depend on: design situations, design supports that make the columns and arms cantilevers, the displacement references for members and surfaces, and the serviceability configuration with its limit values. It ends with the new cross-section optimization for the serviceability limit state and how far its approximation can be trusted.
Webinar language
EnglishRecommended skill level
Skills you will gain
- Create the characteristic, frequent, and quasi-permanent design situations with the combination wizard
- Classify columns and arms as cantilever segments by placing a design support at the start of each
- Choose the displacement reference for members and surfaces so that only the relevant deflection is checked
- Define deflection limits per direction and per action combination in a serviceability configuration
- Optimize parametric cross sections for the serviceability limit state and judge when another iteration is needed
This webinar includes
Webinar content
Andreas Hörold introduces Niklas Wanke, the main developer of the Steel Design add-on, who sets out the three topics: the normative basis for the serviceability limit state, the verification of serviceability in RFEM 6, and the cross-section optimization for serviceability that the session builds up to.
EN 1990 leaves the serviceability criteria to be agreed with the client or set by the National Annex, and defines the characteristic, frequent, and quasi-permanent action combinations. EN 1993 adds no limit values of its own. Exceptions such as crane runway beams and high-bay warehouses have more specific rules.
The example is a three-level cantilever rack: hollow-section columns and arms, a foot section on a nonlinear ground support with anchors, member sets for the columns, and line releases so each shelf acts as a single-span beam. After the loads are reviewed, the combination wizard generates the three serviceability design situations and about a hundred load combinations.
A design support at the foot makes RFEM classify the columns as cantilevers instead of beams, which changes the applicable limits. The check directions are compared, and a slide explains the displacement references: the undeformed system, and deformed segment ends, which the arms need so that the column sway is not counted as their own deflection.
Surfaces have their own deflection tab: the surface type, the reference length, and three displacement references — the undeformed system, a deformed user-defined reference plane through three nodes, and a parallel plane at the point of minimum nodal deformation. The shelves use the user-defined plane, so the rotation of the rack does not count as deflection.
The serviceability configuration holds the limit values: relative, absolute, or combined, set per direction and per action combination, with the defaults taken from literature rather than a standard. It also carries a simplified vibration check and the web breathing check for bridges. The first run leaves the columns and arms far above their limits.
Optimization has long existed for the ultimate limit state, but for serviceability the deformations do not change while sections are swapped. The add-on therefore scales them by the ratio of moments of inertia, weighted when both directions matter, an approximation the presenter is candid about. The column height and wall thickness are then optimized with the width held fixed.
Applying the optimized section and recalculating moves the result slightly, since the structure is not perfectly linear. Because the column rotation is what deflects the arms, a rule of thumb sets a lower target for the columns, and a second iteration brings every check below the limit. The design check details show how deformed segment ends subtract the deflection at the support.
Who this webinar is for
- Engineers who have to agree deflection limits with a client because the Eurocode leaves them open
- Engineers designing racks, platforms, or other steel structures where cantilever deflection governs
- RFEM 6 users who still resize sections by hand until the deflection check passes
Application areas:
Industry:
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Webinars review
I would like to thank you for the webinar on "Torsional Warping (7 DOF)". It was one of the best webinars I have ever seen. Thanks to your clear explanations and illustrative examples, I finally understood several things that I had not fully understood before.
Ing. Aleš Kupča
Statika KUPAL s.r.o.
I really enjoyed the coaching course on dynamic analysis. … It was a good introduction to the seismic design. A particularly positive feature is the option to use the various tools used in the training by downloading a demo version during the training—that was a really good addition.
Karen L.
TÜV NORD Ensys GmbH & Co. KG
I am a student at the Technical University in Nuremberg and am currently working on my master's thesis using Dlubal Software (RSTAB). The coaching course on dynamics (EC 8) was very helpful for me. The course was conducted in an extremely professional manner.
Gleb Chernyshev
Germany
The Concrete Structures EC2 with RFEM 6 course content was very satisfactory and well-structured, making it easy to follow. … In short, the course is interesting and introductory—a perfect introduction to the topic.
M.Sc. V. Zinkevych
Obermeyer Holding GmbH
I would like to thank you for the opportunity to try out RFEM 6. … I would like to mention that I'm excited about how much information and webinars you share.
Ing. Ida Grünwaldová
Czech Republic
Was an excellent Webinar | 2018 NDS CLT Design in RFEM 6! Thank you.
Juan Alberto Tello Fuente
CUMBRA INGENIERIA
Due to your webinars and test versions, I started a new job as structural engineer on January 1, 2023. For this, I would like to thank you and your team.
Dipl.-Ing. Ayman Al Shouha
Germany
Unfortunately, I didn't have the opportunity to follow the live webinar, but due to your recording, which I've watched, I am very excited about the current possibilities of RFEM 6. … I was particularly impressed by the speaker!
Prof. Dr.-Ing. Henning Lungershausen
University of Applied Sciences, Trier
Thank you, the webinar "The Most Common User Errors with RFEM and RSTAB" was very informative!
Dipl.-Ing. Adam Balogh
ThyssenKrupp Industrial Solutions AG
I would like to thank you again for the very good webinar "Stability Analysis in Steel Structures with RFEM and RSTAB". In some points, I was able to get clarity and it helped me a lot. I will probably use this more often in the future.
Dipl.-Ing. Johann Mair
MÜHLBERG Beratende Ingenieure GmbH, Mühlberg + Mair Beratende Ingenieure GmbH
The "Soil-Structure Interaction in RFEM" webinar presentation was excellent and the topic was very interesting.
Prof. Lazaros Vasiliadis
Democritus Univestity of Thrace (DUTH)
The webinar "Design Cold-Formed Steel Sections According to EC3" was great. It was my first webinar and I would like to follow more in the future. Especially for new users/students like me and if too fast, it is very good that it is recorded and you can watch it again.
Veronika Klöck
Germany
Thank you for the webinar "Design Cold-Formed Steel Sections According to Eurocode 3." I really liked it. The webinar recordings are a real plus point. Continue to do so!
Bernd Jäckel
Gesellschaft für Planung und Vermessung mbH
I really enjoy watching the webinars you showcase on YouTube. They helped me to convince my client to recently purchase RFEM. They provide a wealth of information.
William Lefort, P.Eng.
Danwill Canada
I have watched the webinar recording "Design of Cross-Laminated Timber Panels (CLT) According to Eurocode 5" on YouTube, and I am impressed by the program and the very good presentation.
Dipl.-Ing. Lothar Reichle
Ingenieurbüro für Statik und Baukonstruktion
The webinar about RWIND Simulation was very successful! From now on, it is possible to analyze wind forces on geometries of objects that are not regulated in the standard. The wind force assumption according to the standard was often a more or less good estimate.
DI Dr. techn. Wolfgang Billensteiner
Civil Engineering Office DI Dr. Tech. Wolfgang Billensteiner
Your webinar on RWIND Simulation was very impressive. Like the speakers at the info days, the speaker confidently described the performance of the new program.
Ing. Johann Tauß
Austria
RSTAB is a software program that I recently discovered and which is very helpful for the calculation of steel structures. With the webinars available on the Dlubal website, I have familiarized myself with the various functions of the program.
Daisy Amila
Algeria
I watched the webinar "Dlubal Information Day Online 2014 – Part 2: RFEM 5 – Structural Analysis with Finite Elements for Concrete and Steel Structures" from 2014. It is a good and powerful video!
Dipl.-Ing. Thomas Steinkühler
Bojda Planungsgruppe
I've attended the webinar on glass design. Excellent explanation. I don't design glass structures; however, it was very interesting to explore the potential of the software.
Ing. Simone Luca Tanghetti
Studio Tanghetti
I've been using Dlubal's programs for most of my university studies. In the beginning, RFEM was far from being a mainstream software, so I didn't have many colleagues to advise me, but thanks to the well-designed controls and webinars, I quickly learned how to work with it.
Ing. Martin Závacký
Brno University of Technology
The webinar Timber Connection Design in RFEM and RSTAB was very successful! I am particularly pleased that you explained how to select the SFS intec dowel system WS-T. Thank you very much!
Caroline Göttlein
SFS intec
Instructors
Niklas Wanke, M.Sc.
Product Engineering & Customer Support
Niklas builds the steel structure features in Product Engineering and answers the technical questions that users have about them.
Dipl.-Ing. (FH) Andreas Hörold
Marketing & Public Relations
Andreas creates technical content and public relations material for Dlubal and hosts the company's webinars in German and English.
