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EngrUzair

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  1. Like
    EngrUzair got a reaction from Howard Roark in ERROR WARNING IN ETABS   
    This is related to Direct Analysis Method of AISC 360-05, given in Appendix 7 of Part 16.1 of AISC Steel Construction Manual 13th edition 2005.
    Application of this method, using ETABS, SAP2000 etc, has been explained in the following link:
    https://wiki.csiamerica.com/download/attachments/9538116/AISC360-05+Direct+Analysis+Method.pdf
     
    One-way of of checking practical implication of this message is to run the analysis & design twice. Once 'WITHOUT reiteration' and second time 'With reiteration' of analysis and design. Comparing the results of the two runs for the frame members affected by this error, you may very well be clear about how much crucial this error is.
    Please share the conclusions here too, for updating the knowledge of other forum members.
  2. Thanks
    EngrUzair got a reaction from Nawaz Qasim in Steel Deck Slab Design   
    Here are a few links that would give you basic information, to start with the design of steel deck slabs:
     
    1. Composite Steel Floor Deck - Slabs - Steel Deck Institute (http://www.sdi.org/wp-content/uploads/2013/04/SDI_ANSI_C_2011.pdf)
     
    2. COMPOSITE SLABS AND BEAMS USING STEEL DECKING-Best Practice Guide-SCI Publication P300 ( http://smdltd.co.uk/wp-content/uploads/2013/02/SCI-Publication-P300-MCRMA-TP-No.-013-Best-Practice-Guide-REVISED-EDITION.pdf)
     
    3. Composite Deck Catalog - ASC Steel Deck (http://www.ascsd.com/files/floordeck.pdf)
     
    4. Metal Decking Design Guide - New Millennium Building Systems (http://www.newmill.com/pdfs/DeckDesignGuide.pdf)
     
    5. Design of composite steel deck floors for fire (http://www.steelconstruction.info/Design_of_composite_steel_deck_floors_for_fire)
     
     
    If I remember correctly, there is a design example in composite floor design chapter of steel design textbook by McCormac, for calculating number and sizes of shear studs as well.
     
     
    Regards.
     
  3. Like
    EngrUzair reacted to UmarMakhzumi in Is it in my head or is this forum too quite?   
    Part of the reason the forum went quiet as I found out recently was our Anti-Spam system. Almost all new users that registered on the website are now tagged for manual approval by Admins. Since that takes some time, therefore, the new users don’t get approved right away and by the time they get approved, the question for which they wanted to come to the forum is probably solved. We are looking into it. Apart from that, this forum focuses on a very small subset of Civil Engineering professionals - we also do admit that participation level is low as target audience is very limited and there are some challenges that we need to overcome. 
    Thanks. 
  4. Like
    EngrUzair reacted to Waqar Saleem in Career Counselling for Fresh Engineering Graduates   
    Dear fresh engineering Graduates,
    I would like to elevate the engineering graduates and willing to guide them with their career. Anybody who needs to discuss  please feel free to contact me at watsapp 00 92 331 720 4875, text only please.
    I can not promise any job but i could guide you the way for a good career as engineer. I also request other seniors to do that also. 
    I request fresh engineers that do not waste your time in starting career, go for internships to design offices, construction companies, ask seniors to mentor you. When you go for an interview you must know about the company and the job requirements, do not go blunt. Prepare yourself for the job. Allah has blessed you with Engineering Degree, you are in top 5 percent of your Nation. 
    Select your area of practice and go to the seniors of the area ask them what to do and how to do most of them ll guide the way.
     
    Regards
  5. Thanks
    EngrUzair got a reaction from UmarMakhzumi in Bearing capacity   
    AA.  Soil bearing capacity is provided by the client in the shape of site-specific soil investigation report (SSSIR), prepared by a geotechnical engineer for the site area where building is to be constructed. If SSSIR is not available, client should be asked to arrange the same for proper design of foundation. 
    Regards.
  6. Like
    EngrUzair got a reaction from UmarMakhzumi in Billboard Design   
    Asssalam-o-alaikum!
     
    You might need to increase your main member (pipe) size (thereby increasing stiffness), or to add brackets and bracing, to reduce deflection.
     
    BTW... I am unable to understand, why are modelling pipe as shell, instead of frame? What is its basis, and to what advantages it may lead to?
     
    Regards.
  7. Thanks
    EngrUzair got a reaction from Omer Ahmed in Masonry Design Guidelines   
    In general, yes.
     
    However, be careful to check other requirements (especially minimum sizes & reinforcement of confining members, with reference to wall density) for confined masonry design, as given in the document referred in para 1-b of my previous post, and the following guideline (more recent):
     
    http://www.world-housing.net/wp-content/uploads/2011/08/ConfinedMasonryDesignGuide82011.pdf
     
     
    Regards.
  8. Thanks
    EngrUzair got a reaction from Omer Ahmed in Masonry Design Guidelines   
    Junaid,
     
    1. If you go through the following threads, you will find several good references on the subject:
     
       a.   http://www.sepakistan.com/topic/1652-load-bearing-structure-design/?hl=masonry#entry4141
     
       b.   http://www.sepakistan.com/topic/1326-seismic-design-guide-for-masonry-buildings/?hl=masonry
     
       c.   http://www.sepakistan.com/topic/1313-modulus-of-elasticity-of-brick-masonary/?hl=masonry#entry2495
     
       d. http://www.sepakistan.com/topic/1680-the-seismic-performance-of-rcc-frame-buildings-with-masonry-infill-walls/?hl=masonry
     
     
    2. In case of a 3-story house, it would be better to use a framed or confined masonry structure, if the structure would be constructed in a location of seismic zone 2 or higher. Moreover, you would be requiring RC walls too,  for the basement portion. 
     
    Regards.
  9. Like
    EngrUzair got a reaction from Nawaz Qasim in Vierendeel girder   
    The complete reference to the book referred by @Rana is as under:
    'Modern Structural Analysis
    Modelling process and guidance
    By Iain a Macleod
    Published in 2005 by Thomas Telford Publishing.'
    Regards.
  10. Like
    EngrUzair got a reaction from Waqar Saleem in Steel sections & roofing sheets availability in Pakistan   
    AA. Link of a catalogue, providing information about cross-sectional details & weights of different types of steel shapes available in Pakistan, is given below. It also contains list, thicknesses and weights of plain and corrugated steel sheets. Moreover, information about steel door chowkhats is also given therein. Shared for the benefit of all those interested.
    Regards.
    Link:-
    https://www.mwpbnp.com/downloads/Catalogue-mwpbnp.com.pdf
  11. Like
    EngrUzair got a reaction from M.Nisar in Minimum Steel Ratio In Mat   
    Minimum reinforcement in a mat footing, is to be provided as per Section 7.12.2 of ACI 318-08, as specified in ACI Section 15.10.4.
     
    The amount of reinforcement to be provided (e.g., 0.0018 b h for Grade 60 reinforcing steel), is for each face (top or bottom).  This is because of the fact the mat reinforcement is provided to resist tensile stresses (rather than temperature or shrinkage) on the relevant (top or bottom) face of the mat, similar to minimum reinforcement provided in RC beams.
     
    Regards.
  12. Thanks
    EngrUzair got a reaction from UmarMakhzumi in Building Code of Pakistan 2021   
    Assalamo alaikum!
    Good quality seismic hazard maps of BCP-2021 and Tabulated values of Short-period Spectral Acceleration Ss & Long-period Spectral Acceleration S1 etc. for major cities of Pakistan, are available at this Link.
    Regards.
     
  13. Thanks
    EngrUzair got a reaction from UmarMakhzumi in Building Code of Pakistan 2021   
    Assalamo Alaikum!
    Building Code of Pakistan 2021 edition has been printed. PDF version of the same is available at the following link.
    https://drive.google.com/file/d/154K6RIJ0QZJCJ0Q4HsYl-KVqMuJZZF_o/view?fbclid=IwAR3mWSF1X5xBWywdz3-l1kKt7C4HSQi6D4RYZ5RMS0q-eRZ9GGIj8-vJEUk
    Regards.
  14. Thanks
    EngrUzair got a reaction from Howard Roark in Building Code of Pakistan 2021   
    Assalamo Alaikum!
    Building Code of Pakistan 2021 edition has been printed. PDF version of the same is available at the following link.
    https://drive.google.com/file/d/154K6RIJ0QZJCJ0Q4HsYl-KVqMuJZZF_o/view?fbclid=IwAR3mWSF1X5xBWywdz3-l1kKt7C4HSQi6D4RYZ5RMS0q-eRZ9GGIj8-vJEUk
    Regards.
  15. Like
    EngrUzair got a reaction from Talha Farrukh in Building Code of Pakistan 2021   
    Assalamo Alaikum!
    Building Code of Pakistan 2021 edition has been printed. PDF version of the same is available at the following link.
    https://drive.google.com/file/d/154K6RIJ0QZJCJ0Q4HsYl-KVqMuJZZF_o/view?fbclid=IwAR3mWSF1X5xBWywdz3-l1kKt7C4HSQi6D4RYZ5RMS0q-eRZ9GGIj8-vJEUk
    Regards.
  16. Like
    EngrUzair got a reaction from Mina Kromer in ERROR WARNING IN ETABS   
    This is related to Direct Analysis Method of AISC 360-05, given in Appendix 7 of Part 16.1 of AISC Steel Construction Manual 13th edition 2005.
    Application of this method, using ETABS, SAP2000 etc, has been explained in the following link:
    https://wiki.csiamerica.com/download/attachments/9538116/AISC360-05+Direct+Analysis+Method.pdf
     
    One-way of of checking practical implication of this message is to run the analysis & design twice. Once 'WITHOUT reiteration' and second time 'With reiteration' of analysis and design. Comparing the results of the two runs for the frame members affected by this error, you may very well be clear about how much crucial this error is.
    Please share the conclusions here too, for updating the knowledge of other forum members.
  17. Like
    EngrUzair got a reaction from G_Farooq in Load Bearing Structure Design   
    Assalam-o-alaikum!
     
    The term 'load bearing structure' is commonly referred to a structure, in which the superstructure loads are transferred to the foundation, through masonry walls. These walls may consist of plain or reinforced masonry. Here are a few good books dealing with design of structural masonry:
     
    1. Manual for Des of Plain Masonry in Building Structures, Institute of Struct Engineers, UK, 1997
     
    2. Design of Structural Masonry by McKenzie, 2001                            (BS & Eurocode 6 based)
     
    3. Structural masonry designers’ manual by  Curtin et al., 2006          (BS 5628 based)
     
    4. Masonry Structural Design by Klingner,  2010                                 (IBC 2009 & MSJC-2008 based)
     
    5. Design of Reinforced Masonry Structures by Narendra Taly, 2010  (IBC 2009 & MSJC-2008 based)
     
     
    Besides, you may find several other resources on the internet, dealing with design of load bearing masonry structures.
     
     
    Regards.
     
     
     
     
  18. Like
    EngrUzair got a reaction from Hussam Almustafa in UBC 97 Response Spectrum Seismic Provisions   
    Yes. When following procedures of UBC Section 1631.2, R value is not to be used
  19. Like
    EngrUzair got a reaction from UmarMakhzumi in Masonry Design Guidelines   
    In general, yes.
     
    However, be careful to check other requirements (especially minimum sizes & reinforcement of confining members, with reference to wall density) for confined masonry design, as given in the document referred in para 1-b of my previous post, and the following guideline (more recent):
     
    http://www.world-housing.net/wp-content/uploads/2011/08/ConfinedMasonryDesignGuide82011.pdf
     
     
    Regards.
  20. Like
    EngrUzair got a reaction from UmarMakhzumi in Masonry Design Guidelines   
    Junaid,
     
    1. If you go through the following threads, you will find several good references on the subject:
     
       a.   http://www.sepakistan.com/topic/1652-load-bearing-structure-design/?hl=masonry#entry4141
     
       b.   http://www.sepakistan.com/topic/1326-seismic-design-guide-for-masonry-buildings/?hl=masonry
     
       c.   http://www.sepakistan.com/topic/1313-modulus-of-elasticity-of-brick-masonary/?hl=masonry#entry2495
     
       d. http://www.sepakistan.com/topic/1680-the-seismic-performance-of-rcc-frame-buildings-with-masonry-infill-walls/?hl=masonry
     
     
    2. In case of a 3-story house, it would be better to use a framed or confined masonry structure, if the structure would be constructed in a location of seismic zone 2 or higher. Moreover, you would be requiring RC walls too,  for the basement portion. 
     
    Regards.
  21. Thanks
    EngrUzair got a reaction from UmarMakhzumi in Algo Centre Mall Demolition   
    Assalam-o-alaikum!
     
    Here is the case of a civil engineering building, located in Canada, that had to be demolished, after developing structural problems soon after completion of construction. Worth reading by civil, and particularly structural engineers:
     
    http://en.wikipedia.org/wiki/Algo_Centre_Mall
  22. Like
    EngrUzair got a reaction from Rizwanhanif95 in Special Seismic Data Input In Etabs   
    Special seismic data in ETABS, is used for the enhancement of normally calculated seismic forces, in specific conditions as required by Division IV of Chapter 16, or Chapters 18 through 23 of UBC-97.
     
    Inclusion of special seismic data, results in the use of special seismic load combinations of UBC section 1612.4, for the design of structural members. Parameter 'Em', used in these special load combinations, is described in section 1630.1.1 of the code. 
     
    Generally, special seismic load effects should be included in ETABS models, for all those structural elements for which the code (UBC) requires the use of special seismic load combinations of section 16.12.4.
     
    According to Division IV of UBC Chapter 16, special seismic load combinations are to be used in following cases, among others:
    a. For elements supporting discontinuous systems, as described in Section 1630.8.2.
    b. For collector elements, splices, and their connections, in accordance with Section 1633.2.6.
     
     
    Regards.
  23. Thanks
    EngrUzair got a reaction from Omer Ahmed in Shear Reinforcement In Etabs   
    Seismic detailing of beams requires the placement of shear reinforcement at a closer spacing within a length, equal to twice the beam height, from the support face. This is close to span/4 of the beam in many practical cases. Dividing the beam in 4 segments will give you 12 shear reinforcement values in total, with 3 values for each beam segment. Without dividing the beam into segment, you are getting only 3 values for the 18 ft span beam. With 12 values, you can more easily calculate stirrup spacing by adopting a suitable value applicable to each beam  segment. Thus, it would be a lot more easy to detail the stirrups, as compared with the present situation of a single beam without segments or subdivision.
    HTH
    Regards.
  24. Thanks
    EngrUzair got a reaction from Omer Ahmed in Shear Reinforcement In Etabs   
    1. In the following explanation, I am referring to ETABS version 9.7.4, with active units of 'kip-in' for all quantities. You are probably using ETABS 13 or later version. In these later ETABS versions, systems of adoptable units have been improved, and new options of units have also been implemented. However, in order to understand the explanation given in the following, you will need to change active system of units your model to 'kip-in' for all quantities. Otherwise you might miss some important point.  
    2. In case of beams supported at both ends, shear force (& accordingly, shear reinforcement) is more near the beam ends, as compared to middle portion of the beam. For these beams, ETABS indicates shear reinforcement at 3 points along the beam _ at the start, at the middle and at the other end of beam span. If the beam is not subdivided into smaller parts, shear reinforcement value would generally be larger at both ends, as compared to that for the middle portion of the beam.(Beam in your attached image is indicating the similar results.)
    3. Calculation of required stirrup spacing is similar, to that described for the ties in case of columns in my earlier post.
    4. Upto which distance, what stirrup spacing is to be provided depends upon the shear force distribution along the beam, as will be clear from shear force diagram for the controlling load combination. This spacing will however subject to relevant provisions of ACI 318-08 Chapter 21, depending upon the earthquake zone or design category of the area in which your structure is located.
    5. Now referring to the beam shown in your attached image, the value shown in the middle (0.1000), indicates maximum required shear reinforcement applicable to middle portion of the beam, whereas the other two values (0.1521 & 0.1351) are the maximum required shear reinforcement, to be placed at the relevant beam portions adjacent to supports (columns) on the relevant ends.  In case your lengths in 'inches', and shear reinforcement in in 'sq.in/in.' units, you may calculate required stirrup spacing, similar to column tie spacing discussed earlier, keeping in view relevant ACI requirements. 
    6. For exact detailing of the 18 ft span referred beam, following further information is required:
      a. Overall Beam size (width & height)
      b. Image showing required shear reinforcement values, after changing the active units to 'kip-in' for all the structural parameters, similar to ETABS 9. It would be better & simplify the detailing a lot, if the beam is subdivided into 4-equal parts, before analysis.
      c. Earthquake zone or seismic design category of the area in which the structure is located.
      c. Structural frame system used (OMRF, IMRF, SMRF,  etc.)
      d. Minimum reinforcing bar size used for flexural reinforcement of this beam
      e. Preferable bar size for stirrups (Normally #3, or #4 bars are used).
     
    Regards.
     
  25. Thanks
    EngrUzair got a reaction from Omer Ahmed in Shear Reinforcement In Etabs   
    Assalam-o-alaikum!
     
    Shear reinforcement values indicated on the column member are generally the maximum values for the two shear axes, whether these are from on load combo or from two different load combos. Right-cIick on the member reinforcement diagram generally leads straight to load combo resulting in the maximum longitudinal or maximum shear  reinforcement. However, as you have indicated, I am unsure, why this does not always happen. Surely, someone else might be able to explain this.
     
    Interpretation of shear reinforcement value 'Av/s', given by ETABS, is not very difficult.
     
    Since your units are 'kip-in", Av (i.e. cross-sectional area of ties) is in 'sq.in.' and s (i.e., spacing) in 'inches'.
     
    For your case,  Av/s = 0.045.
     
    For 2-legged #3 ties, Av = 0.11x 2 = 0.22 sq. in.
     
    Substitution of value of Av in above equation, results in required tie spacing,  s = 0.22 / 0.045 = 4.88 in.
     
     
    Regards.
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