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EngrUzair

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EngrUzair last won the day on October 11

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About EngrUzair

  • Rank
    Lieutenant Colonel

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  • Gender
    Male
  • Location
    Rawalpindi
  • University
    MSU USA & UET Taxila
  • Employer
    GoP
  • Interests
    Structural loading, RC design, Steel design, Fire damaged structures, Structural evaluation & rehabilitation

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  1. Thickness of footing

    To the point background & design examples prividing step-by-step procedure for the design of combined footings, including determination of thickness, is available at the following link. Design calculations are based on ACI 318-05 requirements. Combined footings Regards.
  2. Plinth Beam

    WA. Spacing of ties for RC columns located in earthquake zone 3 & 4 is governed by Section 21.4.4.2 of ACI 318-05, and other related sections. You may check the required minimum & maximum tie spacing yourself, using the structural information (columns dimensions and bar diameters) for the columns used in the building under consideration. Regards.
  3. Dear colleagues, AA. I am analysing a 2-storey RC frame structure in ETABS version 9. Geometry of the building was first modelled in Autodesk Revit 2017, and then transferred to ETABS using Revit to ETABS exchange file. The model was updated in ETABS 9. However, on trying to save the file, every time following error was encountered. "Error saving text file Separator Wall/Slab Properties-Error 0" (See the attached image.) The model was however being saved, alongwith displaying above-mentioned error message. In the end, when I tried to run the structural model, the program did not run analysis & stopped, after displaying the following message:- "Unable to complete operation 'Run Analysis'!" Keeping in view above situation, here are my questions: a. What may be the source or reason of this error? b. How this error can be rectified using ETABS 9? Regards.
  4. Ductility

    ASTM A615 requirements are given in the attached image.
  5. Ductility

    Elongation Limits are given in the material specifications applicable to the reinforcing bars under consideration. For example, in case of American Codes, these limits are available in relevant ASTM standards (e.g., ASTM A706, ASTM A615 etc.), depending upon which of these specifications correspond the rebars being used. In case of eurocodes, elongation limits should be available in respective eurocode or British Standard (BS 4449 etc), as applicable. Regards.
  6. Difference between Etabs 9.6 vs Etabs2015

    Many major changes & enhancements have been made in ETABS between versions 9.6 and 2015. Details of these enhancements are given in following links:- 1. ETABS 2013 Release Notes v1300.pdf 2. Latest etabs release notes Regards
  7. Shear capacity of Column

    Following article (particularly its first paragraph) may help you understand the role of column ties in resisting shear during an earthquake:- EQ Tip 19.pdf Regards.
  8. Response spectrum

    Check the following link for the required information:- https://wiki.csiamerica.com/display/safe/Import+response-spectrum+load+case+from+ETABS+into+SAFE Regards.
  9. Flange brace design

    I would like to add the following comments to what has been said earlier: 1. The document referred by @BAZ, is available at following link:- AISC-Bracing for stability 2. Additionally, the following research report (especially its chapter 6 & Appendix B ) provides useful information on undrstanding & design of bracing:- Bracing Requirements for Elastic Steel Beams HTH Regards.
  10. Pile Cap Design

    Following link that provides reference to several good documents related to pile cap design (including design examples), might be helpful in this regard:- Pile cap design
  11. Base isolated structures (rubber isolators)

    Do a little search on Google, & you will find a lot of information on Base Isolators. For example, check the following link:- Rubber-based Base Isolators Regards.
  12. Detailed information on Theory, Design & Installation of hilti anchors is available at the following web link:- https://www.hilti.com/content/hilti/W1/US/en/engineering/design-centers/rebar.html Reference guide & software may also be downloaded from this website. Regards
  13. Response Spectrum

    See the reply at the following link:- http://www.sepakistan.com/topic/2441-elcentro-1940-response-spectrum/ Regards.
  14. Elcentro 1940 Response spectrum

    Check the following link:- http://www.vibrationdata.com/elcentro.htm Regards.
  15. ETABS 9.7.4 Runtime Error Message

    AA. Here is the progress & update regarding the problem described in my original post, for the benefit of the interested SEFP users. 1. Automeshing was adopted in the original ETABS 9 model, with a maximum mesh size of 3 ft for the slabs & walls. The slabs included a raft slab as well, for tranferring the reactions to SAFE. 2. The model was being updated in steps, by refining the geometry along various edges of the slabs according to architectural plans at different floors. Model was running fine at all the steps. 3. The problem most probably occurred when the whole model (including the raft slab) was selected through 'Select all' command & automeshed again as stated in para-1 above. This action meshed the raft slab as well.The meshing of raft slab was haphazard in some regions, because of orientation of slab outer edges in different directions. 4. Following steps were taken in order to sort out the error:- a. Trials were made by automeshing the model at two different maximum mesh sizes of 4 ft & 2 ft (one at a time), but without any positive result. b. Third trial was made using 'default' meshing option ( meshing at grids & in Automesh options, by keeping the 'Further subdivide shell/wall in maximum element size of' option UNCHECKED. This trial helped in running the analysis completely, with 2 Warning Messages indicating presence of unconnected point & frame objects at the specified locations. Deletion of these extra objects removed the warning messages. c. Another trial indicated that thr problem is with the meshing of slabs, and not the walls. d. Trying to locate affected element # 22836 through the procedure advised by Rana, indicated that the relevant output table designates the slab & wall elements by the number types F### for slab elements & W### for wall elements. It followed that element numbers (like 22836 etc) are generated during analysis only. The same facts have been stated above by Saad Pervez. Thus, the affected element could not be traced once again. e. Keeping in view suggestion made by EngrJunaid, the affected model was opened in ETABS 2016. This time the affected element was located & found to be present in the automeshed Raft Slab, provided at the base level merely for exporting the Base Reactions to SAFE for further processing there. 5. Replacing the affected Automeshed Raft Slab, with a new unmeshed raft slab & remeshing the floor slabs & rc walls (after selecting the floor slabs & walls separately) at desired maximum mesh size finally solved the problem. In the end, thanks to all (especially @EngrJunaid) for contribution to reach the solution of subject problem, by suggesting various courses of action. Regards.
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