Maximum deflection in a timber beam

[nick.w]

Homework Statement

Particle board flooring (dead load 8 kg/m2 including joist self-weight) is supported by a series
of Radiata pine VSG8, of call size 150 x 50, timber joists running parallel to one other at 450
mm centers and spanning L=3.8 m between supports. The floor supports an imposed load
of 3.5 kPa.
http://img14.imageshack.us/img14/7767/timbertable.png

Assuming strength requirements are OK (they may or may not be), what would be the
maximum deflection (in mm) of the joist?
Assume allowable deflection for the joist is L/350. Is the calculated deflection
acceptable?
NOTE: for this calculation use w = 1.0 * Dead + 1.0 * Live
(use gauged, kiln dried section size for timber section)

Homework Equations

Max Deflection = 5wL4 / (384EI)For the above formulae:
L is the length of the beam,
E is Young’s Modulus (Units Pa, MPa, GPa)
I is the Second Moment of Area of the cross-sectional shape of the beam (units m4 or mm4)

The Attempt at a Solution

I think this is the correct formula but need to be certain. Also how do I find "I" if this is the correct formula.

I also get thrown off by. "use w = 1.0 * Dead + 1.0 * Live" as I have already calculated the UDL in an earlier part of the question using w= 1.2*dead + 1.5*live.

If you guy could point me in the right pirection of which formula to use I would appreciate it.

Regards,
Nick

 

[nick.w]

edit: Just been having a flick through the forums and wondering if I might of put this in the wrong place. Please move if so. Cheers

 

[nick.w]

bump? More info needed?