Floor load width?

[pete74]

Hi there,
I have been checking span tables for replacing parts of a rotten deck. Can I confirm that the "floor load width" is half the distance between bearers (bearer spacing/2)?

Also if someone can confirm that 2 x 240x45 F27 kiln dried hardwood for a single span of 3800mm is suitable? No roof load.

Thanks

[2x4]

To calculate your bearer size accurately FLW needs to be taken into account as well as the live load of thr floor.

But a single span of 3800 with a FLW of 2400 and joist spacings at 450, no roof loads, you could get away with 1 x 240x45 F27 kiln dried hardwood. Depending on the floor live load you will need 2 x 240x45


.

[cherub65]

Also if someone can confirm that 2 x 240x45 F27 kiln dried hardwood for a single span of 3800mm is suitable? No roof load.
Thanks
Could use 2 x 240 x 35 F27 with a FLW up to 3.3m

[bpj1968]

FLW is half the distance between the bearers on EACH side, i.e each bearer supports half the weight
FLW = Bearer spacing/2 * 2.......... or.... bearer spacing on common applications

Dividing by 2 comes into play where the bearer spacing is different on either side, or on the end bearer

Have a look at the Timber Solutions Program (http://www.timber.org.au/menu.asp?id=141) You can plug in all your different variables and it will wolrk it out for you.

It came up that at 3600 span
2 x 240 x 35 F27 with a FLW up to 3.6m
2 x 240 x 45 F27 with a FLW up to 4.9m

Although the load would be at 100% which is not a good idea

I found this pic which shows it a bit better, except the green FLW is a bit long and the 3rd Across bearer B, should in fact be bearer c = (Y+Z)/2

http://toolboxes.flexiblelearning.net.au/demosites/series10/10_01/content/bcgbc4010a/10_floor_systems/09_sub_floor_bearers/images/page_009_floor_loads.gif