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      Eid-ul-Fitr Mubarak   06/25/2017

      Happy Eid-ul-Fitr everyone. May Almighty shower HIS blessings upon you and your family members.
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  • Our picks

    • 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
    • Posting this thread to break the ice. Modelling domes is very easy in Etabs/SAP. All you need to do is to draw the curvature of the dome in elevation by a series of straight lines, but draw only the one half. Then using the apex at centre point, radially extrude the line say 24 times at 15 degree intervals (or 48 times at 7.5 deg intervals. This feature is under Edit> Extrude Lines to areas. You can further use this geometry for Finite Element Analaysis.
      • 22 replies
    • Hello,
       
      I am designing the mosque in zone 4 . The roof of the mosque is a Truss.I have following questions 
       
      1. Do truss rest on the beam ? if yes .? do i have to assign any support conditions ? or etab will selelct by default.
      2. what will be the grade of steel for the truss ? yield or tensile strength. some one told me go for A 36 ( 36,58)
      • 15 replies
    • I accidentally came across these useful case studies, which, I would like to share. You can use them if you are working on a commercial or residential building retrofitting project. These case studies provide insight about seismic retrofitting and also on analytical methods, that are used for building assessment. I would also like to give due credit to people who are involved in these studies. All these studies were performed under a US-Pakistani Joint Cooperation Project. The details for the project are.

       





       

      6-Storey Mixed Use Building in Karachi.pdf

      10-Storey Office Building in Karachi.pdf

      RS-4 Storey Academic Building in Karachi.pdf

      Five Storey Residential Apartment.docx

      Please visit the thread to download the attachments.
      • 2 replies
    • *SEFP Consistent Design*
      *Diaphragm Flexibility*
      *Doc No: 10-00-CD-0004*
      *Date: August 07, 2014*
      I am writing this article about a very important, but mostly neglected topic of flexibility of diaphragm. I used to assume that all reinforced concrete slabs can be treated as rigid diaphragms. But as it turns out, only the slab with span-to-depth (depth is length of slab in direction of lateral loads) ratio of less than 3 and without horizontal irregularity can be treated as rigid diaphragm. The more important thing is that the span-to-depth ratio and horizontal irregularity is not the only criteria and one other factor also needs to be kept in mind before assigning rigid diaphragm to concrete slabs in numerical model of building.
      Another important concept that I learned, and it was a moment of epiphany for me, is about TRANSFER diaphragms. I had posted a topic “Amplification Of Forces In Etabs” earlier in this forum but we were not able to reach at a satisfactory conclusion. Now, I have the answer to that query: Back Stay effect. Another article is required to explain it , and this concept is not discussed in this article. This article is about flexibility of diaphragm.
      Diaphragms are horizontal members of the lateral-force resisting system of building structures. Their function is to distribute inertial forces, generated at its own level, as well as other levels, to vertical members of lateral-force resisting system.
      One kind of diaphragm only distributes inertial forces generated at its own level. This kind of behaviour is observed in buildings where there is a continuity of vertical members of lateral-force resisting system: building should not have a setback or podium at lower levels, or below grade levels. The other kind of diaphragm, known as “Transfer diaphragm”,

      Read more: http://www.sepakistan.com/topic/1480-diaphragm-flexibility/

      • 4 replies
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  • Similar Content

    • By UmarMakhzumi
      Dear All,
      The forum has been recently upgraded with tons of new features. Please take a minute and explore the new items. Your feedback is much appreciated. You can check out the following thread that summarizes biggest changes to forum. 
      Thanks.
       
       
    • By UmarMakhzumi
      Dear All,
      I have just finished modifying a bunch of stuff related to member roles and I am very excited to announce it.
      There are some new member roles that have been created:
      1) SEFP Associate
      As you know that I have been requesting help with a number of stuff on SEFP and there are very generous people who have volunteered. To recognize their effort, I have created this role. An example is @Saad Pervez, who is doing an excellent job running our Social Media pages. From now onwards, you will find him assigned to SEFP Associates. Thanks Saad for your help.
      2) SEFP Contributor
      There are a few members who have been with us through thick and thin. Because, they have regularly answered questions and contributed to forum by not only providing information but their engineering judgement, this role has been created in recognition of their efforts.  @Ayesha has been assigned to this and we look forward to add more members to their club.
      3) SEFP VIP
      @EngrUzair deserves this without any question. He is the most senior member of the forum providing invaluable support. Not only this but he has also been a teacher at our beloved Alma Mater. I have created this category in recognition to his efforts.  We "might" be adding very few people to this role in upcoming years.
      4) Moderators and Super Moderators
      Our current staff consists of @waqar saleem, @Rana and @BAZ. @Rana and @BAZ have global moderation over the forum and @waqar saleem is currently moderating all the technical sections. They all are doing a great job and I am very thankful them. Because of overall moderation assignment, I have split moderators in Super Moderator and Moderators. Supermods might also get portion of Admin rights over coming years. I have a plan for that but nothing set in stone.
      Like always, please provide your feedback and let me know what else should be done/ undone.
      Thanks.
    • By UmarMakhzumi
      All,
      Starting today, I would be experimenting with some advertisement options on the forum. That would include making ads visible to guests (non-registered members) only. It would also help me estimate the amount this site can pay for itself. Right now, the estimated projections are very low in-terms of revenue (5-10% max of yearly budget). Members would always see a clean forum (no ads).  Guests, however would be subjected to Ads.
      Any suggestions or ideas are welcome.
      Thanks.
       
    • By UmarMakhzumi
      Hello Everyone,
      Here is a list of new features in the upcoming update:
      Updates to Editor ( @EngrUzair might like this one )
      Fluid Forum View ( @Rana check this out)
      Reactions
      Recommended Replies (Moderator Related Stuff)
      Content Messages (Moderator Related Stuff)
      Leaderboard Enhancement
      Richer Embeds
      Forcing Members to Complete Profile
      Improvements to Social Sign In
      Clubs  (Clubs will allow forum members to create their own groups in the forum and discuss things other than structural engineering)
      I am very excited about all these improvements. Stay tuned for more. This update is expected to roll out in summer.
      Thanks.
    • By UmarMakhzumi
      All,
      You can now get a free email @sepakistan.com. All you need to have is more than 25 posts (Title of Lieutenant).
      The email is a forwarding email, meaning that you get to keep your original email and all emails sent at your email@sepakistan.com will show up in your original email inbox. 
      Let me know if anyone is interested.
      Thanks.
    • By UmarMakhzumi
      Hello Everyone,
      If you ever wanted to contribute towards SEFP, here is your chance. We at SEFP need help with the following:
      1) 2 volunteers to help us run our Facebook page. If you don't mind taking 10 minutes out each day to share a few articles from this website to the Facebook page, then this position is for you.
      2) SEFP Mentoring Circle Coordinator is required. We are planning to start Mentoring Circle and would need someone to be the co-ordinator of the program. 
      If you are interested, please let me or any other moderators know.
      Thanks.
    • By Rana
      I think its time now to categorize questions based on the difficulty level.
      For example;
      A toddler asking very basic question like what is mass source or time period, should be classified under lets say Easy or 0 or Beginner or Simple etc category. And as such specific moderators should be assigned to take care of that forum.
      Then we can make other sections like moderate or difficult. Where one really need to relearn/review the question and think about the answer carefully.
      I think all the internet is full of the same basic questions like time period, base shear etc. Isnt it the time to take SEFP a step ahead and not just another forum full of the same basic questions? How can we re-categorize the SEFP sections to give it a new feel, not just like concrete, steel, software issues etc. What do you think?
    • By UmarMakhzumi
      Dear All,
      Please see the latest member rank hierarchy that has been implemented. Your feedback is more than welcome.
      Thanks.

    • By waqar saleem
      Dear Friends
      i would like to suggest that if we make city based SEFP chapters for more frequent interactive meetings. What are your suggestions? @admin. subject to admin approval.
       
      Regards
       
    • By UmarMakhzumi
      Hello Everyone,
      I would like to draw your attention to questions being asked in message boxes instead of being posted on forum. The reason I am raising this is that recently I have seen a spike of inbox messages addressed to me asking for solutions rather than the question being posted on the forum. I assume others are getting similar messages. FYI, I don't have access to inboxes and all your conversations are 100% private. I would like to request everyone to please ask questions on the forum and discuss it on the forum instead of inboxes. The reason being that the discussion can be beneficial for the rest of the community and also other members can then critique or appreciate an opinion.
      Let me know should you have any questions.
      Thanks.
  • Recent Discussions

  • Latest Forum and Club Posts

    • thank you for sharing this. I have question about the box shape wall. shouldn't we assign the same pier to the wall that works together? i have highlighted them in the attached Pic.  Furthermore, how do you draw this in Section designer considering having different pier label? 
    • Hi, I was wondering why in some cases when i want to check torsional irregularity in etabs and use Story Max/Avg Drift from Modal explorer,  the software shows both Y and X direction ratio for Earthquake in X direction Or vice versa.  as far as i know when checking for EX with plus and minus Eccentricities, it should only report ratios for X direction not Y!  i should mention that this happen only in few cases!! in most of the time software report only X direction ratio for EX! thanks in advance for your time.
    • WA. Dear Junaid, 1. Your research topic is very important, being directly related to the professional engineering practice. Please do share the results & conclusions here, on completion of your research, for the benefit of forum users. 2. For obtaining relevant literature, you may adopt following methods: a. Your university will certainly be having subscription to one or more research publishing websites (like ScienceDirect etc). If so, you may search & download relevant research material from these websites. b. You may also request your colleagues studying in other universities to do a similar search on the websites subscribed by their institutions, in case their subscribed research sites are different.  c. Use Google search (with pdf option) to find out relevant research material from many other resources (international universities, research sharing sites like Research Gate & more), downloadable free of cost in several cases. Wish you best of luck in your research. Regards.
    • @Ayesha As we are using half scaled Model in our experiment so the objective of this similitude study is to determine a set of principles,correlation and conditions upon which our scaled model can be related to the prototype for predicting prototype performance.
    • In order to study the effect/performance of infill walls we are providing infill walls in our half scaled 2-story RC Frame model which we will be testing on 6DOF Shake Table here in Earthquake Engineering Center, UET Peshawar...
    • Interesting. I also don't have any experience with Similitude Study. I am curious to ask that what is the objective of this study?   
    • Wa alaikum us salam, I dont have any relevant info regarding similitude study but I found your research topic very interesting. By the way, Are you going to consider effect of infill walls as well? Best of luck.   
    • AoA , I am going to start my M.Sc. research on "Similitude study of scaled 3D RC Frame for seismic testing on 6DOF Shake Table". Need your expert opinion on this topic. It will be of great help if anyone on this forum have work on Similitude Study and share their experience,relevant research papers etc Thanks
    • Your question is not clear. If you explain your problem in a bit detail, you may get a more specific reply. However, if the purpose of your question is to know about general procedure of interpreting reinforcements given by SAP2000 software, it is given below. 1. When we design a concrete frame in SAP2000, it gives following different types of reinforcement: a. In case of columns, required areas of main (or vertical) steel bars and lateral (or ties) reinforcement. b.In case of beams, results are in the form of reinforcement areas for bottom & top main bars as well as stirrups. 2. Given area of steel for column vertical bars is to be converted to suitable number of bars (using theoretical bar areas, as we do for manual calculations) according to code requirements in such a way that the provided steel area is either equal to or a bit more than the area required by SAP2000. Similarly, reinforcement areas given for bottom & top bars of beam members are converted to suitable number & sizes of bars, such that provided steel area is either equal to or a bit more than the area required by the software. 3. Reinforcement areas provided by SAP2000 for column ties & beam stirrups can be converted to suitable tie & stirrup size and spacing, similar to that explained in the following thread for ETABS case: HTH Regards.
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