00:01
Hello students, in this question the length of the beam is given as 18 feet.
00:09
So, the allowable stress for the steel is given as 12000 psi for steel and the allowable stress for wood is 900 psi this is for wood.
00:33
And the relation between elastic modulus of steel and wood is given as the relation between the elastic modulus of steel and wood is given as e steel is equal to 20 times of elastic modulus of wood.
00:56
And the modulator ratio is equal to e steel divided by e wood which is equal to 20 it is given.
01:08
Now, we have to calculate the maximum allowable load we have to calculate ok.
01:18
So, the maximum allowable load in the beam has to be found out.
01:35
The required properties for the calculation is given as moment of inertia is 32 .5 inch to the power 4 and i y is equal to 1 .31 inch power 4.
01:53
And the momentum of inertia of wood section has to be calculated that is where i of wood is equal to bh cube divided by 12.
02:07
Therefore, on substituting 12 inch into height is 8 inch the whole cube divided by 12.
02:15
Then it is equal to momentum of inertia of wood is 85 .33 inch to the power 4.
02:24
Now, the transformed moment of inertia has to be calculated.
02:28
Therefore, the transformed moment of inertia is calculated as i t is equal to i w plus 2 into i z into n.
02:43
Therefore, it is equal to on substituting 85 .33 inch power 4 plus 2 into 32 .5 inch power 4 into 20.
02:56
Therefore, i t is equal to 1 .3 sorry it is 1385 .33 inch to the power 4.
03:06
Now, the moment based on the wood we have to calculate moment based on wood...