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About mathias

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  • Birthday 05/01/86

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    Berlin, Germany
  1. I found the following explanation in the book Structural Design of Steelwork to EN 1993 and EN 1994, page 23: "During rolling the whole of the steel section is initially at a uniform temperature, but as the rolling progresses some parts of the cross-section become thinner than others and consequently cool more quickly. Thus, as in the welded joint, the parts which cool last have a residual tensile stress and the parts which cool first may be in compression. Since the cooling rate also affects the yield strength of the steel, the thinner sections tend to have a higher yield stress than the thicker sections. A tensile test piece cut from the thin web of a Universal Beam will probably have a higher yield stress than one cut from the thicker flange. The residual stress and yield stress in rolled sections are also affected by the cold straightening which is necessary for many rolled sections before leaving the mills."
  2. Sarah welcome to! Have you checked the Concrete Centre's publication: 'Multi-Storey Concrete Car Parks'? It's free to download and on page 8 and 9 are presented 5 different concrete slab options for a typical 15.6 x 7.2m grid!
  3. By the way is there any good book or publication (except for EN 206-1...) about RC specifications for ordinary structures according to Eurocodes?
  4. Hello Dik and welcome to DTE! Your design experience will be really useful for all the members! I don't think that Eurocodes will be a problem for you as most of the threads are referred to general structural questions! mathias
  5. Francois, First of all, the wind loads should be calculated according to Eurocode 1 part 1-4 (EN 1991-1-4). There are some design examples on the internet and also a spreadsheet in the Downloads section but I am afraid that it would be difficult for a non-structural engineer to understand and apply them to calculate the wind loads on photovoltaic panels.
  6. Try "-scalelistedit" command! -scalelistedit (don't forget the dash in front of the word) > R (reset) > Y (yes) > E (exit)
  7. Welcome to!
  8. Welcome to! Feel free to post anything you want!
  9. Hi! I have to design a small inclined footbridge of 7m span between two concrete buildings of different height. I have never designed something like this before. Are there any particular aspects I should take into account? What about the supports? Thanks in advance!
  10. Mokshda I also forgot to ask you what is the distance x between the buildings... I think that the facade of your structure adjacent to the tall buildings will not be subjected to wind provided that z-hdis<0 and the area of the shield created by the buildings is greater than the dimensions of your frame. The other sides of the structure will be subjected to wind since they are not shielded!
  11. Hello Mokshda! What are the values of have (average obstruction height of neighbouring structures) h (height of the structure) and z? A multi-storey building has one reference height for every storey. Probably when zstorey-hdis is less than zero, the storey is not subjected to wind (the ground level is raised)!
  12. Hello aciyath! You are right! Sometimes in structural engineering we use simplified and conservative approaches in order to design our structures. The main reason we do this, is because some of the required calculations are very complicated and time consuming. The simplified curtailment rules for slabs are just some simple tips given by the Concrete Centre in order to design the curtailment of slabs easily. If you decide not to use the Concrete Centre's approach and calculate the curtailment lengths by hand you will end up with similar results but not exactly the same! You will easily find out that the results coming from the CC's approach are more conservative! Coming back to your initial question, the underlined percentages and values are coming from the scientific work (experiments, experience gained from numerous design projects etc) of the Concrete Centre's engineers and not from a particular theoretical model.
  13. Hello Takis and welcome to our forum! I hope you like it! You could use the excel spreadsheets from the downloads section... Moreover, this solved example from Access Steel might help you understand the basics for wind load calculations (email registration is required)! Unfortunately the online application Civiltools - EC1 Tools is not available any more... I would be happy to help you with whatever questions you may have about EC1!
  14. Does anybody know what are the appropriate serviceability checks that should be performed to verify the suitability of a cold-formed steel floor joist?
  15. I don't have any particular example for such a tall structure! If you use the British Standards don't forget to calculate the wind loads according to the Directional Method because the structure is higher than 100m. In case you use Eurocodes, the calculation of the structural factor cs*cd might be necessary! In general you have to be very careful with wind load calculations of tall buildings!