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  1. EngrJunaid

    KPK Seismic Field Practicing Manual (Urdu)

    Dear Engineer, KPK Seismic Field Practicing Manual is attached. Field Practice Manual on basics of good construction practices.pdf Thanks.
    5 Points
  2. W.salaam Waqas, We have various Seismic-force resisting systems defined in different codes/standards with different nomenclature. You can study these Systems in detail in these tables; BCP SP-2007, Table 5.13-Structure Systems ASCE 41-13, Seismic Evaluation and Retrofit of Existing Buildings,Table 3-1,Common Building Types ASCE/SEI 7-10, Minimum Design Loads for buildings & other structures,Table 12.2-1 Design Coefficients and Factors for Seismic Force-Resisting Systems Modelling Structure either as BARE FRAME or FRAME with MASONRY INFILL in ETABS/SAP/STAAD PRO/ROBOT Structures/Seismostruct is the designer design approach that how he want to resist the gravity/lateral Loads. By Modelling wall in model it becomes a DUAL System (Concrete Frame with masonry shear walls) BUT the idealization of masonry walls is not as simple as other elements like Beams/columns/slabs/RC Shear walls etc. It requires more experties/understanding (Study Section 11.4-Masonry infills of ASCE 41-13,Seismic Evaluation and Retrofit of Existing Buildings for detail). Proper anchorage should be provided b/w masonry and RC frame. We mostly/commonly design our Concrete structures as BARE FRAME (Moment resisting frame without Infill walls) and assign wall load on the beams. By doing this we are neglecting the masonry walls stiffnesses which results more ductile frame (Ductility is more desirable in structures).Proper steel reinf. detailing is required and gap filled with thermopore or any other insulating material is provided b/w the RC frame and masonry wall (inorder to prevent the hammering action of masonry on RC Frame during EQ). Most of the 2,3 story houses are constructed as CONFINED MASONRY STRUCTURES and these structures perform very well in EQs.
    4 Points
  3. Dear Fellows I have encountered an issue; draftsmen/architects take projects from clients and make structural drawings without calculations and there are engineers whose stamps are available at printing shops which are stamped for very minimal charges. Structural engineers who are stamping as designer and as vetter are having filthy money without fulfilling their duties. These designers and vetters disregard the profession and engineering community, they do not have any ethics and sense of humanity. PEC do nothing or there is no complain against them. Being engineers and specially as structural engineers this is our responsibility to raise this issue to PEC or any other authorities and more to educate our engineering community that have respect and dignity in the profession, one must not disrespect his profession or let disrespected by such black sheep in the community. If a system/community have the ability to spit the wrong things out it remains alive and working perfectly. when system/community allows everything without check, such community is already dead. Structural engineers do not get projects who are working earnestly due to such people. Main aspect of design safety of humanity is at stack . This is totally against the PEC Code of Ethics. This is against the PEC Code of Conduct. Allah has bestowed us with great knowledge and brain to use for serving humanity and earning rizq e halal. We do use our brains rightly. We should stop this corruption by whatever means we can do.We must spit these non-professionals out of our community. This forum is one of the unique voice of structural engineering community, people comes here to get and share knowledge. I request to all the members that will stand with me on this issue. There is immense need to educate people that structural engineering is a business of life/economy saving, the fees structural engineers charge is nothing in comparison to the cost of lives lost during any incident due to incomplete and false designs or more accurate no designs. Regards
    4 Points
  4. EngrJunaid

    Time Period

    In order to find the TIME PERIOD,seismic weight and Base shear used by ETABS in analysis, go to DISPLAY--->Show tables and display "Auto Siesmic Loads" in the Load Definitions under Model definition.... See the attached screen shots...
    3 Points
  5. Rana

    Modelling raft using ETABS and SAFE

    SAFE can include these inverted beams as line elements or shell elements.
    3 Points
  6. Syed Umair Haider

    Issues in ETABS results

    Dear Waseem Your concern is valid but the lower limit given in FEMA example doesn't make sense to me as in a general the usage of time period in seismic analysis is not more than the evaluation of ground acceleration that will be imparted in structure in accordance with specific structural characteristics. Similarly if the specific structural characteristics of a building reveals a time period lesser than generalized approximate time period , then it doesn't make sense to skip the accurate time period and to use approximate one when code itself defines approximate time period as a basis to start analysis for actual T. More interesting is to note that indicated FEMA example is based on 2009 NEHRP seismic provisions , whereas in a separate document issued by NEHRP afterwards (named expanded seismic commentary to ACE-10) it is recommended to use "Tcomp" if "Tcomp < Ta". Moreover, i didn't find any lower bound on time period in UBC97 and even in ASCE 7 which is based on same ELF procedure as given in FEMA example. Therefore, it seems that indicated provisions in FEMA example are overlooked that they have fixed later and usage of Tcomputed if "Tcomputed < Tapproximate" seems valid.
    3 Points
  7. BAZ

    Tie beams design

    The design of tie beam will be governed by amount of differential settlement of the foundation selected for the job at hand. If delta is the differential settlement, then the fixed-end moment due to that value will be: (6EI/L*L)delta. Add the gravity load Fixed End Moment to it, and then distribute this moment among members of beam-column joint according to their flexural stiffness. That is a crude way of proportioning the tie beam.
    3 Points
  8. For the case of frame structure, the key is to have free standing masonry, i.e. provide gaps b/w masonry and frame on sides (between masonry and frame column) and top (between masonry and frame beam) and have it anchored so that it doesn't fall incase of a seismic event (this is very important or the wall will fall down in case of a seismic event). You can also find the attached example useful in understanding how free standing masonry should be anchored to structural system. Masonry Veneer Shelf Angle Design.pdf
    3 Points
  9. waqar saleem

    SEFP Chapters

    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
    3 Points
  10. UmarMakhzumi

    Inbox Communication

    Hello Everyone, I would like to draw your attention to questions being asked in message boxes instead of being posted on forum. The reason I am raising this is that recently I have seen a spike of inbox messages addressed to me asking for solutions rather than the question being posted on the forum. I assume others are getting similar messages. FYI, I don't have access to inboxes and all your conversations are 100% private. I would like to request everyone to please ask questions on the forum and discuss it on the forum instead of inboxes. The reason being that the discussion can be beneficial for the rest of the community and also other members can then critique or appreciate an opinion. Let me know should you have any questions. Thanks.
    3 Points
  11. waqar saleem

    RCC Design Without Modifiers

    good comparison!! it means designing with modifiers will give more practical results and better moment redistribution. what is the effect of modifiers on lateral deflection?
    2 Points
  12. EngrJunaid

    RCC Design Without Modifiers

    See the Attached self explanatory picture.
    2 Points
  13. Syed Umair Haider

    Issues in ETABS results

    I think both ETABS and UBC 97 provisions are correct. As ETABS completely follows UBC97 therefore only UBC's provisions are elaborated below. UBC seismic design philosophy limits the minimum time period (in the form of maximum base shear ) to Ts (UBC response spectrum) which is equivalent to Cv/2.5Ca. For elaboration , V=CV.I.W/R.T Substitutue T=Ts=Cv/2.5Ca in above eqn therefore V=(CV.I.W/R)X(2.5Ca/Cv) i.e V=2.5Ca.I/w (the maximum base shear that ETABS and UBC97 uses) Therefore time period regardless of its shorter value below Ta cannot be lesser than Ts which is in contrast with UBC97 provisions that are inherent in ETABS. However, analysis indicating time period lesser than Ta indicates a over stiff/over design structure, therefore it is recommended to maintain a natural period closer to 0.1x (no of floors).
    2 Points
  14. UmarMakhzumi

    Foundation Design Floodlight Pole

    You should use the load combination with wind loads. I don't know what the latest is for ACI so make sure your factors reflect wind not live load. Assuming we go with 4 bolts as proposed at 12" c/c, You need to design your anchor bolts for tension : T = 40 kip ft / ( 1 ft * 2 bolts) = 20 kips per bolt on tension side. I have used 2 bolts as the other two bolts would be in compression. Shear per bolt would be (assuming 2 bolts take shear) = 1.76/ 2 = Almost 1 kips per bolt. Now with these forces, you need to size your bolt based on ACI Appendix D. Start with a 1" bolt. Have you used Appendix D before? If yes, great. If no, give it a try for a day and if you can't figure out let me know. Thanks.
    2 Points
  15. Engr Waqas

    Good consultants in karachi

    Assalam i alikum friends, What are good consultants in karachi which have experties in building design of low height as well as high rise. Kindly share ur experience and info. Major element i m looking for is good learning environment where we can learn real and correct design practices instead of faulty ones. Also kindly comment whether EA CONSULTANTS from karachi are good in technicalities in structural design or not? If u also can comment or comparison between EA and bilan nd mushtaq consultants it would be of great help. Thanks.
    2 Points
  16. asadishaq

    Good consultants in karachi

    EA consulting is very good organization, they have good projects and have very experienced professionals, working environment is also good they have bridge department and also the building department.On the other hand M&B is equally good as EA they only have Building experts and they are now a days doing very good high rise projects.
    2 Points
  17. EngrUzair

    masnory wall on RCC footing

    A wall footing with an RC beam (of height greater than the thickness of footing slab) will have a greater stiffness than the one without beam. As such, it will have more capacity to resist longitudinal bending of wall / footing caused by any concentrated loads, as well as in spanning over some loose pockets existing within the soil beneath. Regards.
    2 Points
  18. Engr Waqas

    Tie beams design

    Tell me why are you not designing it using software to take care of all the forces for design? More over in my opinion, tie beam grade beam ground beam and plinth beam are not different necessarily. They are just terms to define the type of beam. Tie beam is a beam used to tie two columns for two movememts. Vertically and horizontaly by increasing stiffness of structure there. For example column A and column B are tied.if column B settles, the tie beam will offer a resistance to its settlement by transfering force to column A. Also if column B moves horizontaly, tie beam will tie column B with column A and hence offering a frame actiom to reduce horizontal deflectiom. Tie beams may be at any level. If these are at plinth evel they are called plinth beams where it also helps in soil retaining of inner house area and offer also as support for walls. Plinth beams my also be designed as tie beams or just as plinth beams to support walls etc. Grade beam is a beam cast against earth. If below plinth there is not brick foundation and plinth is supporting wall then this plinth beam also called as grade beam. And grade beam and ground beam is same.
    2 Points
  19. FYI- Video is more related to confined mansonry but shows the out of plane behaviour of wall. Might be of interest to few. Thanks.
    2 Points
  20. EngrUzair

    KPK Seismic Field Practicing Manual (Urdu)

    Very vital information, and in urdu as well for understanding of all. Must be shared with as many construction related people as we can. Thanks @Junaid! for sharing such an important document. Well done!
    2 Points
  21. waqar saleem

    PEB registration of SEFP

    Salam Dear Fellows In SEFP first ever meeting, it was discussed to register SEFP as PEB (Professional Engineering Body) affiliated with PEC to contribute to the engineering community positively and give CPD to registered members. We are here with some ideas and concepts in common like structural engineering and sharing. Hope you all would like this idea of registration. Rregistration/guidelines form is attached for reference to study and to discuss the process and willingness of the members. Regards RegistrationRenewal Form for PEB.doc
    2 Points
  22. Great share.
    2 Points
  23. Great useful sharing Junaid!!!
    2 Points
  24. EngrUzair

    Inbox Communication

    Very important message! I myself have received questions in my inbox more than once, from some of the forum members asking for help on various technical matters. However, I have always advised them to put the questions on the forum, as it has multiple advantages, both for the originator as well as for rest of the forum members. By posting the question on the forum (instead of sending to an inbox), the problem is visible to all the members, and it is likely to get not only a quicker response but more & better responses as well. In addition, the question and responses are helpful for rest of the forum members in general, and those members particularly who do have same problems but somehow (due to shyness etc) couldn't ask the same questions on the forum themselves. In view of the above discussion, I strongly second the opinion of UmarMakhzumi, for posting of problems to the forum itself, instead of sending them to inboxes of moderators or other forum members. Regards.
    2 Points
  25. waqar saleem

    Stiffness Method

    i need some help on stiffness method of analysis anybody having related notes kindly share we are studying Amin ghali's structural analysis book Regards
    1 Points
  26. Rana

    Design of RCC basement walls

    Yes, consider the axial loads and out-of-plane moment for analysis.
    1 Points
  27. Ayesha

    RCC Design Without Modifiers

    How is that possible?
    1 Points
  28. Ayesha

    Time Period

    You can find time period for seismic analysis done through Equivalent Lateral Force procedure by printing the summary sheet.
    1 Points
  29. Abid Qasmi

    Issues in ETABS results

    interesting discussion!!! but how can we check T i.e the fundamental time period in ETABS?
    1 Points
  30. Ayesha

    Detailing Software

    ETABS has a built in detailing feature. https://www.csiamerica.com/products/etabs/features Here are a few others. https://www.s-cube.in/ProductRCDC.aspx http://www.farasaeg.ir/etabsmate_en.htm http://zaxises.com/rcbeamdetailer.htm I have personally tried none of these so can't give you any expert advise about specific softwares.
    1 Points
  31. waqar saleem

    Etabs Load Combinations

    Dear friends what are the most critical load combinations(service and strength) for zone 2B please. Regards
    1 Points
  32. UmarMakhzumi

    Foundation Design Floodlight Pole

    This is a very good point and would result in higher tension. This is a very likely limit state. Thanks.
    1 Points
  33. BAZ

    Foundation Design Floodlight Pole

    In calculating design forces, have you considered the application of point load on a panel, which will support lights, at the top of the pole, in addition to the UDL on the pole itself. Is it possible that only two bolts will be effective in resisting moment for a wind direction in which two bolts will lie on the neutral axis, and the moment arm will be sqrt(2) x 12.
    1 Points
  34. BAZ

    Issues in ETABS results

    My initial post was to point to fellow engineers that one must look at the value of the time period used by the ETABS for calculating the base shear. For normal construction in Pakistan, the construction in which the area of shear walls seldom exceeds 1% of the floor area, the time period of the building should not be significantly less than the value obtained by empirical formulae of UBC 97. If ETABS is using the value which is, say 60%, of that value, then there should be some mistake in modeling, and the design engineer should be aware of that.
    1 Points
  35. UmarMakhzumi

    Good consultants in karachi

    I know someone here who has worked long time in EA. EA has loads of work and lots of engineers as well. Like Asad said, you will get great exposure. On the flip side, salaries would be very low. Things might have changed in recent years so check with someone who is currently working in EA or MB through LinkedIn. Thanks.
    1 Points
  36. UmarMakhzumi

    Foundation Design Floodlight Pole

    Hello Waqar, Do you have the baseplate size from vendor. If yes, what is the bolt pattern (Bolt holes and distance). Also, did the vendor give you design loads for anchor bolts? If yes, great. If you don't have anchor bolt loads, you need to manually calculate wind on the floodlights and pole and the reaction at the base and design anchor bolts and foundation accordingly. If you have the bolt pattern, I can show you how to resolve the forces to anchor bolts and other things that you should keep in mind. For foundation, a square foundation with a concrete pedestal would do the job. Thanks.
    1 Points
  37. Engr Waqas

    KPK Seismic Field Practicing Manual (Urdu)

    Thanks a lot for sharing...
    1 Points
  38. ILYAS

    Tapered column footing design

    just design with width 5ft,this is not big issue.
    1 Points
  39. UmarMakhzumi

    DUAL SYSTEM

    Correct like you said above. Thanks.
    1 Points
  40. Rana

    DUAL SYSTEM

    No way Ilyas. That will reduce the total base shear. Wrong approach.
    1 Points
  41. Saad Pervez

    Issues in ETABS results

    There is no lower limit for T but there is an upper limit for Maximum V, so even if the time period calculated by ETABS is significantly lower than Ta, code provisions for maximum base shear would govern and the calculated value of T would be ignored. Similarly, no vertical distribution of force would take place for a small time period hence your design would still be in reasonable FOS limits.
    1 Points
  42. aslamwalekum , when we design reinforced concrete elements , for beam we take 0.35 , for column and wall we take 0.7 and for slabs we take 0.25 as modifiers , but i read in aci that for servicibilty analysis these modifiers has to increase by 43% which means for beam it become 0.5 , for column and shear walls it become 1.0 and for slab it become 0.35 , by doing this model drift and deflection both reduce to almost half of its original value. one thing more when we do manual check we dont take crack sections , for e.g for simply supported beam the deflection is 5\384 WL^4\EI , here the I (inertia ) is not the for the crack section ,its for the uncracked section , so what modifiers should be use 0.35 or 0.5 or 1.0
    1 Points
  43. ZIA UD DIN

    Conceal Beam

    My friends, How to decide the width of the conceal beam . Which formula is used for it ?Secondly, How to make sure that conceal beam width is sufficient for controlling deflection in it ? Thirdly, if there is any conceal beam supporting a wall on slab. As this conceal beam will only support weight of the wall or also some portion of the slab as well as described by the area distribution method for others beams( L,T Beams) ? Friends I need your replies.
    1 Points
  44. Engr Waqas

    Deflection Calculations : Manual vs Etabs

    Assalam o alaikum, For assuring deflection check of flexural members, we compare immediate deflection due to live load with L/180 or L/360. Also we compare total deflection (sum of immediate deflection due live load and long term deflection due to "dead +sustained loads") with L/240 or L/480. These deflections are calculated using corresponding effective moment of inertia "Ie" using equation 9-8 of section 9.5.2.3. To find out immediate deflection due to dead load we find out it using Ie calculated using cracking moment due to dead loads. To find out immediate deflection due to sustained loads we find out it using cracking moment due to sustained loads. To find out immediate deflection due to D+L we find out it using cracking moment due to dead + live loads. But to find out immediate deflection due to live load, we don't find it using cracking moment due to live load. We find out it by the difference of deflection due to dead + live load with the deflection due to dead load only. as shown by following results of manual calculations (Results from example 10.1 of PCA notes of ACI 318) Del.dead = 0.098 in (calculated using Ma due to dead load only and corresponding Ie came out to be 10648 in4 = i.e. Ig because Ma is less than cracking moment) Del.live = 0.0744 (calculated using Ma due to live only and corresponding Ie came out to be 10648 in4 = i.e. Ig because Ma is less than cracking moment) Del.(dead+live) = 0.344 in (calculated using Ma due to dead+live combo and corresponding Ie came out to be 5345 in4 < Ig because Ma is greater than cracking moment) Note that 0.344 is not the simple sum of 0.098(Del.dead) + 0.0744 (Del.live) because here for Del.live, Ie used was based on live only i.e. Ig =10648 in4; for Del.dead, Ie used was based on dead load only i.e. Ig = 10648 in4; and for Del.(dead+live) Ie used was based on (dead+live) load combo i.e. 5345 in4. All three "Ie" are different". My question is, how to cater this in etabs modeling because in etabs it simply super impose deflections due to dead and live for D+L combo which must not be the case. More over, does modifier 0.35 is enough to cater effect of effective moment of inertia? Thanks.
    1 Points
  45. ILYAS

    plaxis software

    plz can anyone tell me that whether plaxis 2D/3D SOFTWARE JUST ANAYLIZED THE SOIL OR DESIGN also. THANKS
    1 Points
  46. 1.The structural load are so high or soil conditions so poor that spread footings would be exceptionally large. As a general rule of thumb, if spread footing would cover more than 50 % of the building footprint area, a mat or some type of deep foundation will usually be more economical. 2.If the soil is very erratic and prone to excessive differential settlements (heaves). The structural continuity and flexural strength of a raft will bridge over these irregularities. 3.The uplift loads are larger than spread footings can accommodate. The greater weight and continuity of a mat may provide sufficient resistance. 4.The bottom of structure is located below the GWT, so water proofing is an important concern. Because mats are monolithic, they are much easier to waterproof. The weight of mat also helps resist hydrostatic uplift forces from the groundwater.
    1 Points
  47. Abid Qasmi

    How to decide a Raft or a Single Footing?

    Aoa dear S.Es Wat is the criteria for selection of a particular type of a foundation especially with reference to an RCC building? e.g A RAFT or SINGLE FOOTING?
    1 Points
  48. Engr.Usman Javed

    Mat or Raft Footing design

    salaam.. hope so all will be fine i m the civil structure engineer using etabs or sap for designing but i would like to prefer designing by hand calculations.. actually i need the hand calculation for mat or raft design if any one have the calculations regarding these please email or upload it.. i will be very thankful to you..thanks
    1 Points
  49. Mahnoor Khawaja

    Seismic Assessment And Retrofit Design

    this book also useful NED research paper https://www.academia.edu/8983144/A_Practical_Guide_to_Nonlinear_Static_Analysis_of_Reinforced_Concrete_Buildings_with_Masonry_Infill_Walls
    1 Points
  50. Good firms that I have heard about while working are: Arif Associates, Lahore. (Vetted one of their projects) Rizwan Mirza Associates, Lahore. (Heard about them) Design Men, Islamabad. (Heard) AAA Associates (I dont remember the name exactly) ACES, Rawalpindi (Vetted one of their projects) SMK, Karachi (worked mutually) Mustaq & Bilal, Karachi (Heard)
    1 Points