Jump to content
  • Welcome to SEFP!

    Welcome!

    Welcome to our community forums, full of great discussions about Structural Engineering. Please register to become a part of our thriving group or login if you are already registered.

Hira Malik

GLASS DESIGN IN ETABS 2015

Recommended Posts

Attached below is screen shot of a canopy model. the cantilever portion is 24ft glas with supporting beams and 20psf live load. I am not sure how to check the design for a glass slab. How to check shear? What would be the limiting value of shear stress? Like for RC slabs it is 60psf (1.1*SQRT(fc'). What else do i need to check? Like in RC slabs for the moment we provide reinforcement, but how to deal with glass?

Capture.JPG

Share this post


Link to post
Share on other sites

CONSIDER THE SLAB AS SIMPLY SUPPORTED ON BEAMS AND CALCULATE THE MOMENT THEN CALCULATE THE REQUIRED THICKNESS OF GLASS BY COMPARING THE MOMENT WITH THE TENSILE STRENGTH OF GLASS (TENSILE STRENGTH OF GLASS WILL BE PROVIDED BY THE MANUFACTURER)

 

Share this post


Link to post
Share on other sites

jazakAllah. Yes we have demanded the specs from manufacturer. Do i need to change/edit stiffness modifiers for glass? why and how? I have never played with these in any structure before, but now i have been asked to do so ad i have no idea how.

Share this post


Link to post
Share on other sites

Modifiers are related to cracking and loss of stiffness before reaching ultimate limit state (ULS) which happens in concrete. You wouldn't provide stiffness modifiers for steel or glass as there is no cracking before and change in stiffness. Cracking of glass is failure.

Thanks.

Share this post


Link to post
Share on other sites

For the steel canopies with the glass on the top you have to consider few things for the design. As others mentioned you the strength of the glass can be and should be provided by the manufacturers according to your spans and wind load requirements. There is a small software for the glass thickness check saflex which is available for free on net check that to get approximate glass thickness you can put in your initial assumptions for the glass like tampered double glazed with air space  with assumed size etc . This glass thickness can be used for the dead weight calculation to be used in calcs. 

Now for modelling you can model the frame and assign the area shell element with weightless properties. And put your dead loads for glass as well as the framing of the glass with will be provided on the steel to hold the glass panels as oneway loadings on the area elements. Put your live loads mainly for the cleaning purpose on the main steel members as point loads take impact load and apply as pressure load point load on the area element as the glass is tested against the impact of any thing falling on it from a height check the codes there is a value I don't remember now but you can check its steel ball impact test. Also apply the canopy wind loadings you can calculate that from ASCE-7-10 or the check internet for the Australian code it has a special clause for canopy wind laodings. 

Once these loadings are done make you appropriate load combinations and complete your analysis. No need to change any modifiers for steel structure. 

You can check your shear and axial values all along the beams to calculate the connections required for holding the glasses. There area special pressure plates and tobbler coneectors normally supplied by the glass suppler and they are enough for holding the things but still you can verify the small screws provided by the details. 

Please excuse as the dicription is soo long but I hope this will help you. 

Share this post


Link to post
Share on other sites
On 2016-12-16 at 8:59 PM, Yasir Saleem said:

Sir Umer sorry for replying so late as I just saw this today and didn't realize that it's a year old.. 

Thanks for your informative reply @Yasir Saleem. You are more than welcome to contribute to topics irrespective of their posted dates.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Our picks

    • *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
    • 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
    • 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
  • Recently Browsing   0 members

    No registered users viewing this page.

×

Important Information

By using this site, you agree to our Terms of Use and Guidelines.