04-17-2010, 12:52 PM
@kantiman: "natural period 2.37 sec an base shear 1319 kN" and/ or "natural period 0.97 sec and base shear 1320 kN" looks to suspicious to me... I have only experience with Eurocode and for two buildings similar to your described above that I have designed, I've got periods in interval from 0,30-0,45 sec and base shear 10 times your base shear (actually about 14000kN)
for prelimenary calculation of natural period use this two formulas:
1. T = 0,06 × Nf (where Nf = number of floors) in your case it is T = 0,06 × 5 = 0,30 sec
2. T = 0,022 × Hb (where Hb is height of the building from the ground level to the top of the building) in your case it is T = 0,022 × 5 × 3,4 = 0,374 sec
you should check the design for both periods - 0,30 sec and 0,374 sec as well.
concerning the base shear:
It depend on a lot of parameters (according to Eurocode) but in short I can tell you that you can get base shear force using this formula (just prelimenary and use with caution!):
Fb = ag × M
Where ag is ground acceleration in [m/s2], and M is mass of the complete building with live load in it times the corresponding factors in [kg] (e.g. according to EC (just prelimenary!) 100% of dead load + 30% of imposed live load)
PLEASE NOTE: above described formulas are only for evaluation/ prelimenary calculations!
You can find Eurocode 8 posted here:
so you can do the check of the construction on your own...
My best regards.
G
for prelimenary calculation of natural period use this two formulas:
1. T = 0,06 × Nf (where Nf = number of floors) in your case it is T = 0,06 × 5 = 0,30 sec
2. T = 0,022 × Hb (where Hb is height of the building from the ground level to the top of the building) in your case it is T = 0,022 × 5 × 3,4 = 0,374 sec
you should check the design for both periods - 0,30 sec and 0,374 sec as well.
concerning the base shear:
It depend on a lot of parameters (according to Eurocode) but in short I can tell you that you can get base shear force using this formula (just prelimenary and use with caution!):
Fb = ag × M
Where ag is ground acceleration in [m/s2], and M is mass of the complete building with live load in it times the corresponding factors in [kg] (e.g. according to EC (just prelimenary!) 100% of dead load + 30% of imposed live load)
PLEASE NOTE: above described formulas are only for evaluation/ prelimenary calculations!
You can find Eurocode 8 posted here:
Code:
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My best regards.
G
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