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Recent content by Chster6

  1. Chster6

    oversized columns

    Create a simple concrete beam and columns at etabs. Subject it to seismic loading. When you change the size of the columns bigger, the beams framing into it has bigger moments.. so oversize columns can introduce higher moments to the beams?
  2. Chster6

    Base Shear and beam forces

    AELLC, of course the roof being lighter than lower floor means it has smaller moments in beams. You should have used example of floors just below the roof. Also remember the displacement is distributed in each storey of the building so the shear is not really accumulative at lower floor. Any...
  3. Chster6

    Base Shear and beam forces

    So the storey shear at second floor may be lower than the 10th floor yet the accumulated shear in the second floor is more than the 10th floor hence the columns and beams would attract more forces in the second floor? Another thing. When I oversize the Columns at etabs. I noticed the beams...
  4. Chster6

    Base Shear and beam forces

    https://courses.cit.cornell.edu/arch264/calculators/seismic-wind/index.html but see above where shears is highest at top storey and lesser as you go down so how can you say otherwise? Also when changing column sizes to larger ones, the beam moments increased so this means oversizing columns...
  5. Chster6

    oversized columns

    For oversized columns (where it is made larger than needed), can someone confirm that the beams framing into it indeed suffer greater moments during seismic activity?
  6. Chster6

    Base Shear and beam forces

    In a building, the lower floors should have lower horizontal seismic storey forces acting compared to the upper floors from the base shear. But in Etabs, the beams have larger moment at ground floors than upper floors. How come?
  7. Chster6

    Home and a Mall seismic

    How many percentage usually is the effect of these so called "Seismic Zone Factors" and "Soil Profile Types" on the overall strength of the say beams. Would there be as much as twice more flexural bars for example for soft soil versus rock...
  8. Chster6

    Home and a Mall seismic

    cvg, there is a mistake in figure 1 in iriu.edu site, in "exclusively" P-wave, the house should move horizontal, not vertical. In "exclusively" S-wave, the house should move up and down, not horizontal, see animation of the wave motion at: http://www.geo.mtu.edu/UPSeis/waves.html In ubc, soil...
  9. Chster6

    Home and a Mall seismic

    Interesting sites... but rock having larger shear wave velocity value means they have larger or smaller movement? But it is often said rock has better seismic resistance than soil. Why is that.
  10. Chster6

    Home and a Mall seismic

    About this vertical component of the earthquake. Rock has bigger shear wave velocity value. And shear wave is vertical component of the earthquake. Does it mean in rock, the vertical component move so fast or has high frequency making the building vibration like oscillator? But they say rock has...
  11. Chster6

    Home and a Mall seismic

    Periods don't just have to do with the rotational restraint of the foundations and flexibility of the columns but the dead load above which causes more inertia if the load is more. So in the 50kN-m beam in the house, the dead load above is just little since it's residential. In the mall with...
  12. Chster6

    Home and a Mall seismic

    If you create very strong columns braced, then the beams don't have to be strong. If you create average columns not braced, then the beams have to be strong to accommodate bending in the columns, joints and beams. I think you will agree with the above? So is this the sense that stiffness is...
  13. Chster6

    Home and a Mall seismic

    Not a trick question. If the seismic load of the 300kN-m beam is larger.. and the seismic load or inertia from dead load of the 50kN-m beam smaller, then they would be similar in strength? Does any disagree with this?
  14. Chster6

    Home and a Mall seismic

    Let's say there is a home and mall beside each other. The home has typical short beam of 4 meters with let's say 50 Kn-m moment capacity at support while the mall has typical 10 meters span beam with say 300 Kn-m moment capacity at support. If the home has service load moment of 25 Kn-m and the...
  15. Chster6

    Under plates grout

    The 10mm bar shims were removed because it's not in contact with the floor surface. In fact, the angle bar gap is really about 11mm. Windows and frames will be installed over it on Saturday. After I put the grout in the 11mm gap. Would the angle bar on top of it be in contact with it such that...
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