WR1

Revit is super easy (BIM) also learn Robot I would recommend you to go deep in one specific structural software like ETABS and after that learn other softwares. I would recommend you LUSAS, STRAND7, DYNA (each one of them has its own lovely features) then also try learning ARUP GSA. then there are RISA and MIDAS. Personally I am captivated by STRAND7 and GSA right now. ETABS is too common. Bring some variety on your cv. Also explore other materials like glass and aluminium. But learn one software first, later on, on other softwares, you just have to learn the GUI that where are releases option, where are shear or flexural results etc. But first get familiar with all these terminologies in one specific software.

I am working on my thesis that is "Behaviour of super tall buildings under long-period ground waves". Its not totally what you are looking for! It is specific to tall buildings and then retrofitting them for long-period waves like in Japan. Let me know if i can be of any help to you.

u need to study about mesh convergence from any FEA book! it's an art! for usual geometries and normal problems, default values of 1.0 in etabs or safe are okay! but mesh should not affect reactions. it affects strains, displacements, stresses but the reactions in columns which are 1d elements should not be affected. i mean the equilibrium is satisfied!

mesh size of? reinforcement or finite element mesh?

Apart from what Uzair has suggested, I would also recommend you the software for metal deck design. It is COMDEK by Tata Steel. Update: I think they have changed it to "ComFlor" and the link is here http://www.tatasteelconstruction.com/en/about-us/building-envelope-and-structural-decking/technical-information/comflor/software

yeah im talking about this solid block thing! Anyway yes please share. I myself also starting on DIANA and little bit exp on Strand7

One more thing, this is a plain strain problem, where we consider out-of-plane strain to be 0. But there still exists out-of-plane stress that is equal to Poisson's ratio ( normal stress in 1 direction + normal stress in 2 direction). But as you are modelling brick elements, thats not any more a case. Now you are not assuming that certain strain is zero or not! You are now dealing with all stress and strain components turned on!

Very well written Muneeb! Nice effort! Lot of new things for me

Fatima, I am not much exp in brick elements. What brick element you are using? Hex8? If yes then try using higher order elements like Hex16 for example. Because if this is happening due to shear locking then any element that has mid nodes can correct this problem. I think you cannot use plate elements here, but if you were to use plate elements, then there would not be any out-of-plane shear forces Sxy & Syz.

My dear, you must hire a structural engineer for that purpose

you should hire/consult a structural engineer for that. It's not that simple to talk about it here. It involves so many things! Like what is the seismic zone, height of building, use of building, soil type, material strengths etc.

Muneeb thanks for your efforts. You can attach by going to "More Reply Options"

I did some study on this topic on pouring problem of 4.5m thick raft...let me just remember that

Very confusing discussion to me! Some notes: mhdhamood; please be clear and easy in your questions! Let me say what I think about slab system for this issue; 3 different cases 1. Only gravity load is present Slab is checked against out-of-plane bending Punching is checked against P and M arising from these loading 2. Only E loading (actually assume E as horizontal load because E and gravity loads are always accompanies together). Slab will resist this by axial stiffness (in-plane or diaphragm design). And columns will resist this load by bending stiffness. So in slabs, no out-of-plane bending..right? No slab will also have bending moment out-of-plane. Model a one-bay frame and apply a horizontal load of 100KN at LEFT-TOP joint and see the moments in beam. In this case, you will check slab design against axial load and this out-of-plane bending. For punching in this case, you will use this same M. And for axial force (P) P = 0 for one story frame (refer to frame model) P = P from column above for multi-story 3. When E and gravity both acts. For example in combinations including D+L+E There will be additional component of moment here called, P-Delta So you will use M = moment from p-delta + moment from step 1 + moment from step 2 and use P = P from step 1 + P from step 2 of the column above the slab you will use this P and M for calculating punching anywhere in slab location. If you are calculating punching for shear wall, it will follow the same procedure. Having said all this, please correct me if my understanding of this is not upto the highest standard. Thanks. Simplicity is sexy

and how did u apply the axial load? as a point load on a node? if as a point load, then yeah the column will exp some (fake) shear stresses because in reality there is no point load, it should be uniformly distributed on the top surface of this column mesh (remember to reduce load to half on edge nodes, read about consistent vs lumped loads in FEA). Are you using 3d brick elements for the mesh? After doing this, you also need to turn of poissons ratio effect if there is any. Make v=0 and then all shear stresses should be zero.

Attached image is not clear! Does it gives shear stresses near the fixed support? How did you model the fixed supports? One middle point fixed or how?

You must check punching for all load cases. If (1.2Dead+1Live+1EQ) giving you more forces you should check punching on that. But also remember that, you should check both axial plus moment. So may be you are getting more M in in this combination but axial force is less. So you should check which load combination is giving you more shear stress. You should all load combinations whether it is EQ or gravity or W anything.

In my understanding these are NOT 2 different methods; This is just a differentiation; There are two torsions; 1. Compatibility torsion (where redistribution of moments take place) like slab on beams 2. Equilibrium torsion (where there is no path available for redistribution of moments, like a cantilever slab resting on a beam) These are not two different methods of analysis in ACI or ETABS. This is just to distinguish the cases. That is why it does not matter in ETABS because in ETABS loads will follow the paths that is available. So does not matter if it is case 1 or 2, apply J modifiers but watch for slab moments. Also make sure your detailing handles all these issues. For example if the beam is torsionally too stiff as compared to slab, it will take more moment as compared to slab, and if you are applying less J modifier to beam then make sure the detailing also follows the same approach. (try to increase bottom reinforcement of slab).

Well, I am not sure what you are asking, but punching is when the load acts lateral (perpendicular) to the surface...Like gravity load on slab and then below is the column that can punch through. But EQ is lateral loading which comes on vertical elements let's say a shear wall which is supported by top and bottom slab. So you mean to say, you wanna check punching of shear wall through slab horizontally?

They are doing it right. It depends on you. It is the beauty of the structures that they will behave the way you designed them. When reducing the torsion modifier for beams that are failing to a value approx equal to 0 then watch for the increased moments in slabs. If you put the reinforcement in slab for additional moment then it is ok! It depends upon the relative stiffness of beam and slab that how much load beam will take (Torsion, moment etc).

Yes Muneeb is right about sudden geometry irregularity in column size. Please make sure you take this effect.

a. yes I agree with you b. It might be SAFE, it might not. depends on the moment diagram which depends on the base fixity (pin or fixed). You must design it properly. If this is an interior column then it should be okay (only P and no M). c. If it was enlarged eccentrically, yes you have to account for the moment M = P.e

Yeah you are right but I was doubtful abt your model if the moment is less than the cracking moment. But good finding.

I am sure SAFE is doing it properly but I cannot think an example which can clear your doubts. When you are specifiying additional reinforcement it is affecting the whole model not just the cantilever slab. So it is changing the I eff or I crack of whole model. (Reinf changing I so I affects M).

Muneeb, this is automatic feature. As you keep on posting more posts, it will automatically be removed.