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Showing content with the highest reputation on 12/30/15 in all areas

  1. WR1

    Oct 26, 2015 Earthquake

    Let's continue it by saying that all parties are equally responsible.
    1 point
  2. MS Structural engineering, UET Lahore Go for it if you have interests in structures. Will open new horizons of knowledge even if later you want to switch to project management. Good to be a technical project manager. Or just keep going in structures. In short MS is highlight recommended plus I think UET is quite flexible in it's programs regarding duration (part time/evening etc). MS Construction Engineering & Management, NUST Islamabad Depends on your interests and if the location suits you. MS Disaster Management, NUST Risalpur Not much scope in Pakistan (i think), plus location is total no-no.
    1 point
  3. Salam. Here are my few chunks for freshers looking for specialization. You must know why they are doing their masters in a particular subject. One must have some inner feeling for the MS subject. It is ideal to have some field experience before deciding for specialization. One or two years Internship/job clears the mind and makes more productive, efficient specialized engineers. During internship/job seek somebody to mentor you and groom your inner interests. Discuss with seniors, collect good literature relevant to your interest, analyse the job market. This two years experience, working on your specialization interests will make your future career brilliant. If you can manage go for foreign specialization. If not go for MS which adds to your professional degrees. There are MS degrees which are not approved by PEC as professional MS degree. Other senior members might have good suggestions. WARNING! these are totally my views, everybody knows himself better and knows his/her situation best. May Allah en-light us all for the both worlds. Regards
    1 point
  4. Despite of being a structural engineer, with due regard to above statements,i would like to disagree with I personally feel that our nation has no geo-technical awareness at all. We are ready to pay architects which in turn pay a negligible amount to structural engineer, but we never bother to consult any geotechnical specialist, and many catastrophic failures are due to failure of soil not structure. we want beauty of facade and don't care about anything below grade, which in turn don't care about our structure. and in my opinion collapse of factory in lahore was also due to soil failure. Thank you
    1 point
  5. IMO, it is not an error, rather it is a warning message indicating that UBC wind analysis results might not be reliable, if the building being analyzed is more than 400 feet high. This is in accordance with requirements of UBC-97 section 1615, which requires that approved national standards (e.g., ASCE 7 etc), shall be used for wind design of buildings over 400 feet in height, among others. Moreover,AFAIK, you may still run your model (even after display of this warning message), by pressing OK button again and again (although analysis results might not be acceptable). Regards.
    1 point
  6. WR1

    Slab Design

    Middle strip, column strip is for manual design. You can use the same in SAFE. But you can also draw unit width strips in x and y directions irrespective of column locations and put reinforcement according to that. At the end FE results from SAFE show you stress results and you have to satisfy that with reinforcement. Its not compulsory to draw strips as just column and middle strips. In SAFE a design strip can be of any width, usually 1m/1ft wide
    1 point
  7. When ever we say Allowable bearing capacity, It can be either Gross allowable bearing capacity or net allowable bearing capacity. And it is the most important thing to decide when to add over burden, when to subtract and when not to. More over keep this equation before you for equilibrium q(all.gross) > P/A +Y.Df where q(all.gross) = gross bearing capacity Y.Df = Backfill load P/A = Applied pressure q(all.net) = q(all.gross)-Y.df = (P/A +Y.Df) - Y.Df hence for equilibrium q(all.net) > P/A where q(all.net) = net allowable bearing capacity Y.Df = Backfill load P/A = Applied pressure So gross bearing capacity is capacity available to bear pressure of existing soil as well as applied loads and net bearing capacity is capacity available to bear just applied pressures because pressure caused by existing soil has already been deducted. Case when NOT to deduct over burden Lets say in my geotechnical report i have been provided by NET bearing capacity of 1 tsf at a depth of 5 ft. Now it means at 5 ft depth, soil is capable to bear pressure of 1 tsf IN EXCESS of existing soil. Because it is NET allowable bearing pressure and pressure of existing soil has already been subtracted/balanced from bearing capacity. Now only extra available bearing capacity is reported as net. The soil can bear 1 tsf of EXTERNAL/APPLIED pressure which includes load of above structure as well as load of footing. Load of footing is also external and applied. In this case, you need not to deduct over burden because over burden is already deducted and you are provided with NET bearing capacity. But If you have bearing capacity at 5 ft depth but in return you have plan to backfill upto 7 ft, then obviously extra 2 ft soil is applied pressure. which you need to either add in applied pressure or you should deduct it from the bearing capacity. Case when to deduct over burden But if my geotech report says me that at 5 ft depth, i have 1.25 tsf GROSS allowable bearing capacity. Now it means my soil is capable to bear 1.25 tsf pressure including pressure caused by existing soil. Because it is gross allowable bearing pressure and i have not subtracted pressure of existing soil. The soil can bear 1.25 tsf of total pressure which includes EXTERNAL/APPLIED pressure caused by load of above structure including load of footing, and pressure caused by existing soil . In this case, for the sake of sizing of footing, you need to to deduct weight of over burden soil so that so may find out net bearing capacity available to resist applied load of structure and footing. Note that, after deducting the pressure caused by existing soil i.e. Y.Df = 110*5 = 550 psf = 0.25 tsf, we again get the same 1tsf bearing capacity available for external/applied loads. Case when to ADD over burden Now Let say you are given with any of capacity. Let say Net allowable capacity of 1tsf at 5 ft depth. But you know that you are not going to backfill the foundation (in case of basement etc), then NOT ONLY this 1 tsf is available for applied pressure but also that 0.25tsf available which was going to be consumed by existing soil backfill. Now you can add this 0.25tsf to your net bearing capacity to get bearing capacity, available for external loads and you need to find out size of foundation according to this available bearing capacity.
    1 point
  8. All three approaches exist there. First approach deducts over burden ( which is the most common approach) Second approach is to go straight a way with B.C at that depth, this has many observations and is not practiced widely because 1) Soil has to bear load of super structure along with load of foundation 2) Allowable B.C is calculated on certain assumptions as well which are catred for by placing a factor of safety of 2 to 3. But keeping in view the factor of safety, we calculate size of footing on service load. So factor of safety has already been relied up on in terms of sizing the footings. Third approach is to add up the weight of excavated soil in B.c values. This is generally done for deep excavations like two or three basements. But with that approach geotechnical engineer recommends that excavated surface should not be left open for longer period. If one has excavated the site and there comes a halt in construction after excavation then site must be rechecked by geotechnical engineer before placing of foundation. This is so because soil starts to get relaxed and if cracks get developed then provision of adding up weight of excavated soil does not remain valid.
    1 point
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