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EngrUzair last won the day on February 19

EngrUzair had the most liked content!

About EngrUzair

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    MSU USA & UET Taxila
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    Structural loading, RC design, Steel design, Fire damaged structures, Structural evaluation & rehabilitation

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  1. ACI detailing and design manual

    Firstly, conversion of reinforcement area for flexural (longitudial) beam reinforcement to 'number of bars' is similar to that for the vertical reinforcement of columns. However, for deciding the 'number of bars provided' in case of beams, we round the calculated value to next higher integer number only, whether it is even or odd. For example, if required steel area is 0.9 sq.in., and #5 bar is to be used, then required number of bars =0.9/0.307=2.93. In this case, we may use 3 #5 bars for the beam. (Whereas, in case of a square or rectangular column, we needed to use at least 4 bars.) Secondly, in case of a beam, required number of bars are to be provided along the relevant (top or bottom) face of the beam only, depending upon whether we are detailing the reinforcement for the negative or positive bending moment. In case, required number of bars (as calculated in previous paragraph) exceeds the maximum number of bars permissible in one layer, required number of bars will be provided in layers, separated vertically by spacers. Thirdly, total area of reinforcement provided, must be within the steel areas corresponding to Minimum & Maximum steel ratios prescribed by ACI 318 for the beams. Fourthly, detailing of all type of beam reinforcement needs be in accordance with relevant provisions of ACI 318 and ACI 315 (whether seismic or non-seismic, as applicable). Out of three reinforcement values shown along (the top or bottom side of) a beam, two outer values (0.9 & 0.9 at left & right sides of top face, and 0.6 & 0.4 at left & right sides of bottom face of the beam under discussion) indicate the amount of reinforcing steel required at the relevant (top & bottom) faces of the two supports. Whereas, the middle values (0.2 on the top, & the 0.6 on the bottom side) indicate the amount of reinforcing steel required at the mispan of the beam, on the top & bottom faces respectively. HTH Regards.
  2. ACI detailing and design manual

    When the amount of required area of vertical reinforcement for a column is known (as we normally obtain from structural software like ETABS & SAP2000 etc.), its detailing involves following steps: a. Converting the reinforcement into number of bars. Actually required number of bars is calculated by dividing the area of reinforcement by the area of different bars one by one. For example, in the stated case, required number of bars for a #6 vertical bar (bar cross-sectional area=0.44 sq.in.) will be 4.5/.44=10.22 bars. For a #5 bar (bar area=0.307 sq.in.) will be 4.5/.307=14.6 bars. Similarly, for a #8 bar (bar area=0.785 sq.in.), required number of bars will be 4.5/.785=5.7 bars. b. Selecting the number of bars to be provided. Following are the important points to be considered while deciding 'bar size' and 'number of bars provided'. (1) Number of selected bars is generally an even number. For square or rectangular columns, minimum 4 vertical bars are required. Whereas for curcular columns, at least 6 bars are required. number.The 'number of bars provided' is obtained by rounding up the required number of bars to next higher even number. Based on calculations made in the previous paragraph, 12 #6, 16 #5 or 6 #8 vertical bars may be used to furnish a reinforcement area of 4.5 sq.in. in the given column. (2) The area of provided bars must be equal or a bit more than the required reinforcement area obtained from design calculations (or a structural software). (3) The configuration of selected bars & placement of ties within the column cross-section, should be in line with the following code provisions: i. ACI 315 Figures 13 and 14 (column bar configurations) ii. ACI 318-08 Section 7.7 (concrete cover requirements) iii. Applicable provisions of ACI 318-08 Chapter 21, keeping in view the seismic requirements & structural frame type. Regards.
  3. Depth of Foundation

    It generally depends upon soil bearing capacity & will be recommended by the geotech engineer in soil investigation report (SIR) of a particular site. In case of non-availability of SIR, even for some nearby site, IMHO foundation depth should not be less than about 3 ft. Regards.
  4. Importing of etabs 9.7.4 file to 2016

    Normally, a lower version file may be opened directly in a later version of same software. So, start ETABS 2016 & try to open your older version .edb file directly. In case it does not work, you my use text input file (having .et extension) of your ETABS 9.7.4 model, for importing it into ETABS 2016. If you still face some problem, describe it here, for further advice.
  5. Concrete in Joint

    Consult the structural engineer who has prepared working drawings, for a proper advice. It is possible that this factor might have been taken care of, while preparing structural drawings. Regards.
  6. Web sidesway buckling and web compression buckling

    Following links might be useful in understanding the two concepts:- 1. Sidesway Web Buckling of Steel Beams 2. Revisiting Web Compression Buckling for Wide Flange Sections Regards.
  7. point load on slab in Etabs

    Create a point on the desired location (using manual meshing, or dummy beams etc) and apply the point load as a vertical force on that point. Regards.
  8. FPSC has advertised BPS-17 jobs for Civil, Electrical & Mechanical Engineers as well as for Architects & Town Planners in MES (Military Engineer Service) under Ministry of Defence. More than 40 vacancies have been advertised for each of these categories. Spread this information among your colleagues for all those interested in these job. Last date for applying is 18-12-2017. See the following link for detailed advertisement. http://www.fpsc.gov.pk/icms/user/jobs.php
  9. Slab on grade

    Check the following thread for some good references related to the design of slabs on grade:- http://www.sepakistan.com/topic/2513-design-floor-slab-in-grade/ Regards.
  10. Cold Formed Steel Design

    Both are the same. For more details, check this Link. Regards.
  11. Determination of Critical Buckling Load

    Buckling load is calculated in accordance with Section 6.3 of Eurocode 3 (EN 1993-1-1) that includes relevant formulas as well as buckling curves. This information is generally available in Eurocode 3 based Steel Design books in the chapters dealing with compression members. One such book is, "Structural Steelwork Design to Limit State Theory, 4th edition, by Dennis Lam et al." Regards.
  12. moment of inertia in shear walls

    In this connection, you might like to have a look on this link that contains a very useful discussion on use of cracked sections in the stiffness analysis of reinforced concrete members. Regards.
  13. RC Embedded Columns

    Yes. In both cases, you should include the said column in your model. It will make your structural framing more stable, due to availability of an additional vertical support for the superstructure. Regards.
  14. Pre-stressed Double Tee Design

    Check the following link:- Replacement of Line Loads acting on slabs to equivalent Uniformly Distributed Loads Regards.
  15. design Floor Slab in Grade

    1. First of all, you need to understand how to design the slab on grade (SOG) through hand calculations. Later on, you may develop a spreadsheet or use some patent software to do it using a computer. 2. The references given above provide design methods (pca, WRI, COE etc), dealing with different types of SOG (e.g., unreinforced, reinforced concrete, post-tensioned etc.) subjected to various types of loads (uniform, line, wheel & post loads). 3. Before starting the design, you will need to go through the reference available with you (i.e., ACI 360), and a. Select the SOG type from the Section 7 onwards, applicable to your case. b. Study the design requirements from the relevant section c. Determine the type and intensity of various loads, the slab will be subjected to during service. d. Solve the relevant design examples, given in the appendices of ACI 360 to understand various design parameters, charts, equations & their application to the design. e. Using the design prameters applicable to your slab, design the SOG by following the procedure adopted in the reference design example. HTH Regards.

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