Showing posts with label imposed load. Show all posts
Showing posts with label imposed load. Show all posts

Sunday, March 11, 2012

Basic Loading Calculations (Beams & Slabs) 1 - Prologue - Le Personal Notes

Load Transfer From :
Roof > Slabs > Beam > Column > Floor > Foundation

2 types of loads : Imposed Load & Dead Load

Imposed Load (IL): 
  • Furnitures
  • Human
  • Any Temporary Loads
Dead Load (DL):
  • Beam
  • Slab
  • Column
  • The weight of the building itself 
If ratio of Lx : Ly equal or smaller than 2, = one -way slab = Lx / Ly  > or =  2

If ratio of Lx : Lbigger than 2, = two -way slab = Lx / Ly  <  2

Standard Factor Of Safety (F.O.S.) of:
  • Imposed Load : 1.4 Gk
  • Dead Load : 1.6 Qk
  • Thus load combination formulae :  1.4 Gk  (DL) +  1.6 Q (IL)
  • Assuming that 1.4 and 1.6 is a constant
  • The Dead Load (DL) and Imposed Load (IL) is a variable.
Example :

(A)




1.       List out the available information (assuming that IL and DL values had been given) :
a.       IL = 2.5 kN/m2

b.      DL = 3.0 kN/ m2

c.       Density of Concrete = 24 kN/ m2

2.       Determine the type of load transfer on the slab :
a.       Lx / Ly = 9/3 = 3>2 , thus a one-way slab

3.       Determine the beam that react to the weight of the slab :
a.       Since it’s a one-way beam , only half of the slab weight acted on the beam

4.       Calculate the Combination load using the formula:
a.       Design Load, a = 1.4 Gk  (DL) +  1.6 Qk  (IL)

b.      Design Load, a = 1.4 Gk  (3.0) +  1.6 Qk  (2.5)

c.       Design Load, a = 8.2 kN/ m2

d.      *note that the answer is actually amount of weight acting on 1 m2 area

5.       Calculate the Effective Area, Aeff :
a.       Effective Area, Aeff = Lx x ½ (Ly)

b.      Effective Area, Aeff = 9 x 1.5

c.       Effective Area, Aeff = 13.5 m2

6.       Calculate the Concentrated Load, W :
a.       Concentrated Load, W = 8.2 kN/ m2 x 13.5 m2

b.      Concentrated Load, W = 110.7 kN

c.       Thus, the final answer, W = 110.7 kN, which is the total load acted on the beam



(B)

  


How much is the load acted each on 1m across the beam?
1.       Just simply divide the final answer from (A) with the total length of the beam.

a.       Design Load, a = 110.7 kN /  9 m

b.      Design Load, a = 0.91 kN/ m