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Salam

Dr.Amjad Saqib!!! I love this person for his efforts to reduce the poverty with dignity. Founder of Akhuwat Foundation speaks from his heart,wondefully . Listen to his speech at TEDx

 

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  • Our picks

    • AoA all,

      Is it mandatory to do column concreting upto the soffit of the beam in a single pour ?

      What code says about the construction/cold joint location in column ?

      Majority of the contractors are pouring the column concrete upto the soffit of the beam (full height of the column), some contractors leave the column height about 9" to 12" below the beam level and then fill this 9" to 12" column height with the beams & slab concreting. On one site column concreting was stopped at the mid height and the remaining half was filled on the next day.

      Thanks

       

       
      • 4 replies
    • AOA 

      i am facing problems in shear wall design .what are the pier and spandral ?what will be the difference when we assign pier or spandral? without assigning these the shear wall design is incomplete .

      i am taking about etabsv16

      someone have document about shear wall design plz provide it 

      thank you

       
      • 9 replies
    • Salam Members,

      Congratulations to Engineers, PEC has become full signatory of Washington Accord, what are the benefits to Pakistani engineers for this agreement. 

       

      Regards   

       

       
      • 3 replies
    • Please clarify the following confusions one by one:-

       

      1. If we run P-delta analysis in ETABS, then should we ignore stiffness property modifiers for beams and columns? I have heard that if we perform P-delta analysis and apply stiffness modifiers at the same time then the moment magnification process is doubled...?

       

      2. ETABS considers selenderness of a column by applying moment magnification factors. If we run P-delta analysis also, does it mean that the selenderness of column is being over-estimated? I mean once the moments are magnified in P-delta analysis process and again through moment magnification process?

       

      Please help me understand the software myth and clarify above confusions.
      • 1 reply
    • Assalam o alaikum.
      According to ACI 12.5.2,
      development length for fc' = 3000, fy=60000, for normal weight concrete and epoxy less reinforcement, The required development length comes out to be
      for #3 = 8.2 inch
      for #4 = 10.95 inch
      for #6 = 16.42 inch
      for #8 = 21.9 inch
       
      And if in my case, ACI 12.5.3 is not fulfilled, it means now i have to provide ldh as mentioned above. ldh is STRAIGHT EMBEDMENT LENGTH + RADIUS OF BEND + ONE BAR DIAMETER as shown in figure attached. Now my question is, if in my case, main reinforcement of beam is of #6 and #4, minimum column size required will be 18 inch and 12 inch respectively. Lets say by any means, i can not select #4, #3 bars and size of column where bars are to be terminated is 12 inch, how to fullfil this development length???
      • 11 replies
    • Dear all,

      I am trying to design shearwalls through ETABS with temperature load applied over shell. At various location, spandral section fails in Shear due to temperature and piers (sometime in shear, mostly in flexure).  (See Attached Image)

      Certainly all the problem in Shearwalls are due to temperature. I don't want to increase cross section of spandral or pier at some location just due to temperature load case as it will appears non-uniform with rest of the wall. 

      I have seen stiffness modifier affect distribution of forces and also rigid/semi rigid daiphragm assumption. 

       

      Can anybody guide how to properly design the shear wall with temperature load applied in ETABS or share any similar experience. Thanks in Advance.    
      • 15 replies
    • ENGINEERS;
      I WILL LOOSE MY BRAIN FROM ETABS. 
      I DECIDED TO MAKE MANUAL MESHING FROM AREA ELEMENTS BESIDE EACH OTHER AND EVERY HING WAS FINE .
      BUT AFTER DEVISION SAY 7*7 ELEMNTS FOR EVERY BIG ELEMENT AND MAKING ETABS CHECH..................THEN 500 ERROR MESSAGE THAT ALL ELEMNTS ARE CLOSE TO EACH OTHER.  WHAT ARE GOING...... SOMEONE TELL ME PLEASE...... I WILL LOST MY WORK
      • 6 replies
    • Assalam o alaikum.
      I have just designed a frame structure with SMRF. The out put of shear seams weird to me. Column reports design shear Av/s as 0.045. (Images are attached). but when i right click the member, it must show me the most critical case HIGHLIGHTED AUTOMATICALLY. But it highlights load combo 38 (auto-generated combos have been used) which reports Av/s as 0.038. And 0.045 value is at combo 32. Is their any logic behind it?? More over how to interpret this Av/s?? means 0.045 in kip-in units means what? How can i convert this into spacing?? 
      • 9 replies
    • Hello everyone, I hope all of you will be fine. In etabs when we apply Response Spectrum loading on a multistoried building with 2 basement floors. At what floor level this loading will be applied as in equivalent static seismic analysis, we can apply EQX & EQY on any floor we like as this option is available in etabs but the problem is with response spectrum and time history analysis. please if someone knows and have the experince, share it i shall be very thankful.  
      • 5 replies
    • Salaikom dear professionals,
      First of all I would like to express my sincere thanks to the initiators of this forum for establishing such an exceptional atmosphere for knowledge/experience sharing, I it is really useful, In fact since I have found the forum I am mostly online and busy reading the posts. I would also like to thank the members for their professional comments and advice.
      As my first post in this forum I would like to ask the following queries:
      1-After running the analysis and design when I check the DESIGN DATA through Display >> Show Tables >> DESIGN DATA >> Concrete Frame Output, there is no specific message in Column Summary Data and Beam Summary Data, but in Joint summary data it is showing that “Joint B/C check not done”. Does anyone has any idea? I am sharing the ETABS model for your information and easy reference.
      ETABS MODEL.zip
      2- ETABS provides greater area of steel in the upper column than the column at BASE, perhaps due to higher moment. Could someone explain why this is so? In practice should we maintain maximum steel in both stories? Or we shall follow what the software suggests?
      3- Beside considering the minimum thickness required for deflection control of Beam as per Table 9.a Chapter 9 ACI-318 , using concrete crack behavior in ETABS and checking story drift, Do we have to check the deflection of beams for the serviceability propose elsewhere in ETBAS? If yes, Could anyone explain it?
      Regards, and look forward to any explanation
      • 13 replies
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    • By Waqas Haider
      Assalam o alaikum, 
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      Salam
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    • By Kasim
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  • Recent Discussions

  • Latest Forum and Club Posts

    • salam everyone  how to calculate spring constant from soil report data and it will be assign through the length of pile .?  
    • Yes sir, agree just forget to put that one in.  Thanks,
    • Thanks for the great reply Yasir. I will just add that the member nodes should be continuous (able to transfer moment + shear) once they are broken or else the model would be unstable. Thanks.
    • As Uzair mentioned up there that is one way for the modelling of sag rods, but as per my experience it do not give satisfactory results. several reasons behind this one as it depends upon your building geometry like size of purlins or beams you want to bridge and there length as well. The sag rods behave as pin elements at the ends and they are most of the time lose tight with the main member which is a bit difficult to model, they come to action only in case of severe loading (Normally they are just holding the alignment of main beams). if you model them as per above method you have to break the main member at the connection point to send through the force to them so they act as tension member but as same time you have to make them pin assign due to which you will get very strange deflection shapes for the model, even the force distribution changes alot  in some cases again depending upon geometry. Some time you hit the right nodes but most of the time results are a bit strange and some compromise is done in design of members, the best way i figured out is that you model line elements (with none material or frame property just null element) as sag rods and apply loading keep the main member as one piece without break and take out the member force generated in the null element. Design the tension rod or sag rod for that force manually as per required code.   The above method is more suitable for building braces for lateral actions or tension rods for hanging cantilevers where high loads are expected.  Thanks
    • Dear colleagues! Assalamo-alaikum. Congratulations to all on 70th anniversary of independence of Pakistan. May Allah bless us & make it Pakistan (i.e., the land of pure people) in the real sense. Regards.  
    • SALAM to all members, I am doing my master research in PBD for tall building ....i have applied response spectrum analysis on my building....My supervisor asked me to calculate momment in my shear wall for the first governing modes of my building so that I can assign fiber hinges at where momment is critical.........(as far as my knowledge I can calculate displacement or  velocity  for each mode and then combine them by CQC or SRSS manually as given in alan william and many other books).My question is that how can we calculate momment for suppose first two modes (both manually and procedure to calculate it by  ETABS) through out the wall.........I shall be very thankfull to all senior members who would help me in this regard as early as possible.
    • Hello Rahim, I have lost the document while changing laptops. Sorry. Thanks.
    • Sir, can you kindly provide the above Supplement pdf
    • 1. AFAIK ETABS 2016 has the capabilty to design CMU (Concrete Masonry Units) Shear Walls only. The design is carried out in accordance with ACI 530-11 requirements. See the following link for the relevant Design Manual: https://www.google.com.pk/url?sa=t&source=web&rct=j&url=http://docs.csiamerica.com/manuals/etabs/Shear%20Wall%20Design/SWD-ACI-530-11.pdf&ved=0ahUKEwjfxIbNqcPVAhXGto8KHbPiAhgQFggtMAE&usg=AFQjCNHg0YZpIutlVDDoPos320qUvD_90g 2. Several masonry design software, other than Prokon ( https://www.prokon.com/design/masonry-design ) mentioned in previous post, are available  on the internet. Here are the links of a few of thesr masonry design software:- a. MasterKey - BS & Eurocodes based ( http://www.masterseries.com/product-specific/masonry-design) b. NCMA Structural Masonry Design software; IBC, TMS402 & ASCE 7 based ( http://www.ncma-cpu.org/ProductSubCats.aspx?SubCatID=42) c. MASS - Canadian code based ( www.masonryanalysisstructuralsystems.com ) d. GEO5 Masonry Wall; Euro code & Australian code etc ( http://www.finesoftware.eu/geotechnical-software/masonry-wall/) e. DigitalCanal Masonry Wall - ACI 318-11 & IBC 2012 ( http://digitalcanalstructural.com/masonry-wall/ 3. A simple internet search will yield names & links for many more masonry design programs, if needed. Regards.
    • Try to use Prokon to design brick/concrete masonry.. Its design is straightforward .. from load distribution of slab, corresponding slab load transferring into the supporting walls are calculated, the load keeps on adding down from each floor together with the wall line loads down the wall footings. Fk for characteristic compressive strength for the wall is calculated from the ultimate loads, the fk of the bricks or concrete blocks used taken from the manufacturer is checked then with the calculated one, if the brick/concrete blocks are adequate to bear the ultimate loads. Try to consult ACI 530-1999 or BS 5628-1985 for this type of design. 
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