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  2. I found another thread on the forum where isolated foundation rotation was discussed. The author (posted excerpt from Pauley and Priestley ) recommends modelling isolated foundation using a rotational spring to avoid unexpected column hinging at top of lower story columns. FYI, Thanks.
  3. Today
  4. I posted the query because I recently read two articles: one is FOUNDATIONS FOR SHEAR WALL STRUCTURES by J.R. Binney and T Paulay, and the other one FOUNDATIONS FOR CAPACITY DESIGNED S T R U C T U R E S by P.W. Taylor and R.L. Williams. @Rana : This is not enough. These details ensure the development of column hinge at the bottom if it is possible. And that "if" depends on the soil-structure interaction and the strength of the soil. If the soil is strong enough to resist bearing pressure corresponding to forces (axial load + moment) that it may experience when the column will be in inelastic range (capacity design approach), and if you have designed the footing for the moment that it may experience when hinge (capacity design approach) will form in the column, which is, of course, greater than the moment that you will get from ETABS for the design Earthquake, then the hinge will form in the column. If the above scenario is not feasible then you may proportion the footing to allow the rocking behavior so that energy may be dissipated provided footing rotation is in permissible limits, which will depend on the soil-rotation relationship. @umer: In MAT, or other connected foundation types, the third option is to allow nonlinear behavior in the foundation. In that case, the foundation should be detailed for attaining necessary ductility levels. These things are not discussed in the ACI code. I have not read these things in RCC books as well.
  5. Thanks Rana. This would be applicable for all foundations. @BAZ, Sir when you mentioned isolated foundations only, is there any specific item other than what Rana has described that you would were thinking. I don't have any idea about this topic other than that isolated foundations can rotate but don't know how that would be related to this discussions. Thanks.
  6. Modeling of pile with soil behavior

    thank you for your guidance
  7. what else is required in conventional codal design other than proper detailing and developing bars for ductility? I found this useful; https://www.housingauthority.gov.hk/tc/common/pdf/business-partnerships/resources/concrete.pdf
  8. 2D-Plate Analysis -Safe

  9. Look for the staad manuals for software related nomenclature. structural concepts are same and you could refer to any good book on rc/masonry design or can ask a specific question here.
  10. Modeling of pile with soil behavior

    1-as we have To follow simplified approach in structural software to model geotechnical properties,as you are right that modulus of different soil will be different therefore i have uesd a word" accordingly". 2-anyway there are many other ways to incorporate the lateral stiffness/vertical stiffness approxiamately,Thanks .
  11. Thanks Umar this will help (y)
  12. Yesterday
  13. Can anyone tell me how to do traditional Design of residential buildings in Pakistan using STAAD PRO? Any tutorial will be appreciated
  14. Does anyone practice the design philosophy that ensures the formation of plastic hinges at the bottom of the column, near the foundation, for isolated footing?
  15. 2D-Plate Analysis -Safe

    Yes, 2D plate analysis should be used. 3D analysis will give wrong results as the raft has confinement on all sides. If you are using the 3D analysis, then you must add lateral springs as well to get better results.
  16. Lower compressive strength of concrete

    1) Refer to ACI 214R-02 Page No. 214R-9,10,11 and 13 2) Refer ACI 301M-99 3) Refer ACI 318 M-11 Page No. 74

    Transfer slab/beam, and their supporting members, requires to be detailed for the forces resulting from the inelastic response of pick -up the column.
  18. Reading results in STAAD Pro

    WSalaam Hali, The following topic discusses how to resolve forces in lb-in/in or any other format for plates, shells etc. The discussion is for SAP2K but I would assume the same would be applicable for Staad (you can check its manual). Thanks.
  19. 2D-Plate Analysis -Safe

    Plate elements by default consider shear deformations. If you use shell elements, then then would ignore the shear deformation. I think your question should be that Is the analysis using Shell Elements is correct for deep rafts as they ignore shear deformations.

    What are your specific concerns? Do you want to discuss the important things to consider while designing pick up column?
  21. Modeling of pile with soil behavior

    Thanks for the great reply. I will just add that modulus of different soil layers is different so the pile to be divided either equally within each layer. Thanks
  22. Last week
  23. RT @alowid: بدأت تأليف كتاب في سيرة الشيخ #وليد_العلي مع تضمين مواقف للشيخ #فهد_الحسيني فمن عنده قصص أو صور فليرسلها تفضلا واتساب0096599944…


    In seismic analysis, the issue of picked up RC columns need careful consideration. Please share your experience for tall (G+40) RC structure..
  25. Salam everyone, I have recently started using STAAD Pro for design of concrete. Need help with understanding how to read the plate stress contours to come up with design moment values. The values on the plate read for example 2500 lb-in/in. How do I interpret these results? Thanks
  26. Modeling of pile with soil behavior

    1-Horizental (lateral stiffness) or vertical spring constant?and it will be better that you you go for point spring in case of pile rather then line spring. 2-multiply the modulus of subgrade reaction with area of pile. 3-divide the pile length into equal parts(to add modulus of subgrade reaction accordingly) and, assign the joint at intervals and then apply joint spring. 4-you will get approximately not exactly bending moments/shear force depending upon the pile end condition fixity or partially fixed ,free whatever you have.
  27. salam everyone how to calculate spring constant from soil report data and it will be assign through the length of pile .?
  28. How to define frame properties for sag rod in etabs

    Yes sir, agree just forget to put that one in. Thanks,
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