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Rana last won the day on January 27

Rana had the most liked content!

About Rana

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    NUST + Heriot Watt
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    FEA, Tall/long structures, Dynamic analysis, Seismic, Travelling, Writing

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  1. Foundation Design

    Foundation should be designed for response spectrum cases too if they are used for super structure design also.
  2. raft punching

    Moments should not differ by that much amount (10x in your case). Yes you can calculate punching directly based on 450kn.m like in RCM Builder. We use it daily, its my company software. Or you can calculate manually or by any sheet. I dont know why you are getting huge moment in SAFE. Probably because of the loading from raft? check your model again or try checking only on self weight...
  3. FEM- internal meshing

    Yes the program still divides it. Thats why I say ETABS is not a true FEA tool. They have made it damn easy for majority of the engineers. It is not for FEA analysts.
  4. Structural Systems according to UBC-97

    There is no seismic design category in UBC. Its simply zone 2B in UBC. What you probably meant is the equivalent seismic design category of ASCE 7 related to zone 2B of UBC. If so, then you have to convert your zone 2b spectra to ASCE 7 spectra and to find out S1 and Ss. After that you can find out the sdc from ASCE tables based on this S1, Ss and Fa and Fv.
  5. Calculate T in ETABS

    Who said so? For majority of the buildings (low rise) dynamic time period is way lesser than 1.4Ta. Read code to understand about these limits. It should have been; if Tmode>1.4Ta then T=1.4Ta. Just a typo mistake i think, but inside ETABS it takes it correctly for both UBC and IBC/ASCE codes. Don't worry.
  6. moment of inertia in shear walls

    pretty simple check stresses in walls, if they are more than modulus of rupture they are cracked, use 0.35 otherwise they are un-cracked so use 0.7. Then iterate. Cracked walls will be in high rise with more seismic loads. See above.
  7. Temperature Loading on walls.

    What are the restraints to circular walls? Is it open from top? The circular shape is it self restraining (hoop stresses). Outward and inward? Yes, if bowing action but you need to apply gradient temperature then in softwares. Sign will determine if it bows outwards or inwards. Which software you are talking about? Yes application of any load in any software and even in papers depends on the direction in which you want to apply. Yes 1.2 factor for T, but not all combinations. You need to find out logically where you will need to use 1.2T. I mean effects should not be counteracting.
  8. Cost per square feet

    I can connect you with some on this if you like...
  9. Raft Modeling In Etabs

    Make one and post for us please!
  10. Shear wall design

    How do I know what is your confusion without you writing it down for me?
  11. Bearing Capacity

    I dont think code dictates that but yes common sense sure does. I wouldnt design foundation unless from some source I have the bearing capacity information. Even if it is preliminary design and you put a note that "the foundations have been designed assuming.....capacity", you should do some research of nearyby buildings. You cant just guess, i think.
  12. Required force method

    First off, is your Limcon cracked or purchases? If cracked, there are certain variables in the software that are "FIXED". They do not change if you change values. So beware!
  13. raft punching

    Depends if the sheet is correct? Does the sheet take into account moments?
  14. Structural Systems according to UBC-97

    Really? Moment frame type has nothing to do with location except some limitations in codes. Can't you have special moment frame in Zone 2? Yes, you can! Type depends on the ductility and framing of building system. Do you think it has enough ductility? If yes then it could be special even in Zone 0. But obviously it will cost more to provide that ductility and detailing for zone 0. But generally speaking, you could design special frames in zone 2B or ordinary in higher zones, depends on the framing.
  15. Assigning Of Temperature Load In Etabs And Safe

    not true in all cases. uncontrolled internal temperature has the same effects like outside sun heat on the structure. There are usually documents stating weather station data. You should use mean yearly average highs and lows not daily. It also depends on approval authority. For example in Dubai, limit is 45m. Expansion joints are nice from structural point of view only. As a structural engineer, Id try my best to avoid them. Construction isnt that easy for expansion joints. What about water leakage? Except ground floor columns and walls that will have huge forces due to restrain (supports). This is my opinion. I don't think T+E should be added.

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