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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

 

Edited by UmarMakhzumi

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  • Our picks

    • Dear All,

      The forum has been updated today with a lot new features.

      You can find the list of all the new improvements by visiting this website.

      Some highlights are:

      1) Improved Search Features


      2) Emoji

      Emoji support is now available in all editors.


      Do check out the link posted above for the complete list.

      One additional announcement that I would like to make is that with reference to last forum update post (read below),  @Rana and @BAZ are forum Admins now. I think it was important to do as it brings more transparency for the forum and also helps spread the responsibility. The forum belongs to the members so it never made sense for one person to be Admin,

      As always, feedback is much appreciated.

      Thanks for taking the time out to read this update.

      Cheers!

       
      • 2 replies
    • Hi guys just to discuss with you my understanding of crack widths in Environmental structures according to ACI. 

       

      ---------------------------

      Normal structures

      ---------------------------

       

      1. ACI 318-95 based on statistical method of Gergely & Lutz 1968 limits Z based on exposure. We are calculating crack widths here. (Normal structures)

       

      2. ACI 318-99 proposed limiting the spacing and removed actually calculating the width and also removed the exposure conditions. For example for beams and one-way slabs s (in) = 540/fs -2.5cc or in other words limiting the fs=0.6fy  (For normal structures)

       

      3. ACI 224R-01 references method 1 and 2 above and 3 european codes.

      The most confusing part is the table in which Nawy suggests 0.1mm crack width for water-tight structures. The whole document is for normal structures except this line. And people are following this line and refer to this document for water tight structures. I mean its just a suggestion and by the way this method 1 is obsolete now since ACI 318-99 (see point 2 above).

       

      ---------------------------

      Water tight structures

      ---------------------------

       

      1. ACI 318-08 states clearly that for watertight structures ACI 350-06 codes should be used. 

       

      2. ACI 224.4R-13 also specifically states that for watertight structures walls in section 7.4, we should use ACI 350-06. 

       

      3. ACI 350-06 for water tight structures does not recommend calculating a number for crack width but rather limiting max steel stress in bars to be 20k ksi or fs=0.33fy for normal conditions.

       

      ---------------------------------------------------------------------------------------------------------

      To sum it up, 

       

      Philosophy of crack width control is not to calculate probable crack widths but to limit the max stress in steel bars.

       

      For normal structures: fs=0.6fy and for water tight structures fs=0.33fy
      • 1 reply
    • Hi

      I want to know the use of diaphragms in etabs. i discus many people who are use etabs but i can't get justified answer about the application of etabs.

      I read the Technical reference  of  Etabs, where they write about Diaphragms. i get two type of diaphragms (plate or shell and joint or beam). 

      My question.

      1. When do i use Shell diaphragms (if floor present ) 

      2.When do i use joint diaphragms ( grade beam level where no slab are provide) 

       

      NB: Diaphragms use to transfer the lateral load to the resisting element ( frame such as column. beam,shear wall) 
      • 2 replies
    • *SEFP Consistent Design*<br style="color:#272a34">*Pile Design*<br style="color:#272a34">*Doc No: 10-00-CD-0005*<br style="color:#272a34">*Date: Nov 21, 2017*<br style="color:#272a34">
       

      This article is intended to cover design of piles using Ultimate Limit State (ULS) method. The use of ULS method is fairly new for geotechnical design (last decade). The method is being used in multiple countries now (Canada, Australia etc). The following items shall be discussed:

      Overview


      Geotechnical Design of Piles (Compression Loads, Tension Loads and Lateral Loads)


      Structural Design of Piles (Covering both Concrete and Steel)


      Connection of Pile with the foundation (Covering both Concrete and Steel)


      Pile Group Settlement


      Things to consider



       

      1. Overview

      Piles provide a suitable load path to transfer super-structure loads to foundation where shallow foundation are not suitable - this can be due to a number of reasons like existing space constraints or suitable soil strata is not present immediately below structure. Other uses can be to meet design requirements like to have reduced settlement etc.

      This article shall cover the use of straight shaft cast-in-place concrete piles and straight shaft driven steel pipe piles. There are a number of additional piles types like belled concrete piles, precast concrete piles, screw / helical steel piles etc but the discussion to choose a suitable pile type is not in the intended scope of this article. The article is intended  to discuss design requirements for straight shaft piles only (both concrete and steel) . The aforementioned topic about pile selection is a very diverse subject and requires a separate discussion on its own.

      Click on the link to read the full article.
       
      • 9 replies
    • I am suppose to design a pile foundation for a machine weighing approximately 50 tons and with an operational loading of 100 tons. 
      I ll appreciate your help in terms of guidance & provision of notes...  
       
      Thank you..
      • 36 replies
    • Material behavior can be idealized as consisting of an 'elastic' domain and a 'plastic' domain. For almost 200 years, structural design has been
      based on an elastic theory which assumes that structures display a linear response throughout their loading history, ignoring the post-yielding
      stage of behavior. Current design practice for reinforced concrete structures is a curious blend of elastic analysis to compute forces and moments, plasticity theory to proportion cross-sections for the moment and axial, load, and empirical mumbo-jumbo to proportion members for shear.

       

      From the book "Design of Concrete Structures with Stress Fields" by A. Muttoni,  J. Schwartz and  B.Thurliman.

       
      • 0 replies
    • 9th International Civil Engineering Conference (ICEC 2017), December 22-23, 2017, Karachi, Pakistan
      Dear Fellow Researchers, Academicians, and research students,

       

      NED University of Engineering & Technology in collaboration with Institution of Engineers Pakistan (IEP) is organizing 9th International Civil Engineering Conference (ICEC 2017) on December 22-23, 2017 at Karachi, Pakistan.

       The congress details are available at its website www.neduet.edu.pk/icec

       Also attached is congress flyer for information and dissemination among your peers.

       Abstracts submission deadline has been extended till October 31, 2017.

      Please click on the link to see the full description.
      • 0 replies
    • 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

       

       
      • 5 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

       
      • 10 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
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  • Similar Content

    • By UmarMakhzumi
      Dear All,
      The forum has been updated today with a lot new features.
      You can find the list of all the new improvements by visiting this website.
      Some highlights are:
      1) Improved Search Features

      2) Emoji
      Emoji support is now available in all editors.

      3) Member profile cover photos are now clickable and can be viewed as a full image. Do check out mine as it is a very beautiful waterfall snap taken by yours truly. 😃
      Do check out the link posted above for the complete list.
      One additional announcement that I would like to make is that with reference to last forum update post (read below),  @Rana and @BAZ are forum Admins now. I think it was important to do as it brings more transparency for the forum and also helps spread the responsibility. The forum belongs to the members so it never made sense for one person to be Admin,
      As always, feedback is much appreciated.
      Thanks for taking the time out to read this update.
      Cheers!
       
    • By miqureshi77
      Dear Developers of SE PAKISTAN, 
      I would like to congrats you for making this useful website and thanks for your efforts and dedication for continues working on this site.
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    • 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.

  • Recent Discussions

  • Latest Forum and Club Posts

    • Could you help me understand how moment will be distributed in two ends of beams if one end of beam is fixed and other end is partially fixed? Say, previous 24ft beam with 15k/ft udl....FEM are -720 k-ft both sides.....now one of end has been partially released so that it can develop 360k-ft how will moment be distributed to other end...I am getting 900 k-ft at fully fixed end and shears at 2 ends became 157.5 and 202.5 kips..., I fail understand how to solve this indeterminate beam with one partial fixed end...   Thanks for your help
    • The settlement is likely due to weakening of soil support beneath the columns. There may be several reasons for this, like ingress of moisture in the underneath soil, sudden subsidence of some underground cavity etc. This may be investigated through some geotech engineer. Underground water tank, some nearby leaking water supply or sewerage line might also be the reason for weakening of the soil. To start with, these should also be checked & any leakage observed should be promptly & properly rectified.  Futher advice can be given on knowing the results of geotechnical investigation, carried out for determining the most likely cause of settlement.
    • Thanks for your reply. Actually your blog was one of the first I studied before doing it. 
      I understood it now. ETABS is using equation like M=(n/(n-1))*4EI/L*theta. so rotational stifness constant k=(n/(n-1))*2EI/L. If you are reducing stiffness on both sides consider using spring constant of (n/(n-1))*2EI/L n=% of moment to be resisted.....for n=1 we will get fully fixed, for n=0 we will get fully hinged.  The graph can be considered to be n(Y-Axis) and (n/(1-n))*2 as X axis. The data makes sense now. i am worried about 3D now, I have 55 story building in which i have to model connection loss in terms of decrease of stiffness. I don't know if I could use 
    • What kind of foundation system is there. you can consult a geotechnical engineer as well to get some option interms of soil improvement etc. From a structural point of view, you can  always introduce more columns and reduce load per existing column to reduce settlement. Thanks. 
    • plz help me out of this problem.. the foundation is settling down week by week. it is a warehouse. a big  Under ground water tank is adjacent to the failed column. we have only little space to work. this is in dubai. Suggestions please what so i can do. plz do reply
    • First, the stiffness of this beam is 2EI/L. See here; http://classes.mst.edu/civeng217/concept/12/03/index.html Second, see the fixed end beam in this link, hope it clarifies. Do share the findings afterwards please. https://waseemrana.com/2013/04/16/how-to-partial-fixity-in-etabs/
    • I am trying to understand how rotational spring constants work in ETABS. I have considered 24ft long beam with 15kips udl applied so that fixed end moment is 720k-ft I assume that spring constant will be function of EI/L. I assumed that ETABS would have linear spring, so that if I find lowest spring constant to give me 720k-ft fixed end moment, I would half that spring constant to give me half restain so that moment will be 260k-ft. In reality results are far from it. the graph attached shows factor which I multiplied to (EI/L) to get spring constant in kip-in/rad in X axis and Y axis shows corresponding end moment/720. Can somebody explain how etabs spring constant work so I find factors representing fraction of total restrain.
    • Did you got the answer of your question?
    • PEB structures are a special type of steel structures. These are less common in our country, as compared to RC structures . Accordingly, very few firms or structural engineers design these structures. Some locally known such firms include Zamil Steel, PEB Steel, Mammut, Izhar Steel etc. Larger firms have their own design manuals (and in some cases, their own special  software as well), which you may search on the internet.  UmarMakhzumi  has pointed out to the proper source & authority dealing with this type of structures.  Analysis & design of PEB structures is similar to normal steel structures. However, MBMA Manual provides better design aids (based mainly on ASCE 7), especially with reference to application of wind loads to this type of steel structures. In addition, it has several detailed wind analysis examples dealing with Enclosed, Partially Enclosed & Open type steel buildings. This manual will be a very useful source for understanding the design of steel & PEB structures covered in MBMA , in case you already have a good command on the use of AISC Manual of Steel Construction.  
    • MBMA guidelines might be used in PEB structures. I know @BAZ used to have a MBMA design document. http://www.mbma.com/  
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