Is this a Structural Integrity Bug

[Tahaan]

While experimenting with S.I calculations I have found a few cases where the result does not match up with what it should be, at least as far as my understanding goes.

 

Here I am building a platform 8x9 from woodframes, supported on the 4 corners.

 

Each "corner" provides 2 fully supported Glue sides with a max horizontal support of 40, meaning the structure max weight is 320.

 

Note that it is not possible to fill in the entire platform, since that would have a weight of 340 and indeed it fails if we trr to go over 320.

 

Now the problem I have is when leaving out specific blocks from the platform, to reduce the number of fully supported glue sides from 8 to 7.

 

Here I have an example. The max load allowed by 7 glue sides is then 280 (7 x 40)

 

However this structure with a weight of 285 is not failing.

 

 

The sole frame on the right of the bottom-left pillar is not part of the structure - I should have taken a screenshot without it but it neither adds not remves from the part of the structure in question since it is islated. Note that the same is NOT true for the 2x2 area around the bottom right pillar. The frame to the left of that corner is attached to the rest of the structure via the frame directly above it, and removing either of those two will cause a failure in the structure.

 

The 49 frames making up the suspended load are all wood frames. One of these have a steel block on top of it, taking the load of the platform from 245 to 285.

 

So by this calculation the platform is over its maximum load.

 

Is this a bug or is my understanding flawed? If it is a bug then I can report it properly in the bugs area.

[theFlu]

Umm.. your understanding sounds good. Your weight on the steel block though - aren't those 20 a pop, not 40? That would make it 49*5+20 = 265, which would be less than 7*40=280.

 

Then again, I wouldn't count on the SI maths on any stucture, it seems to do plenty of weird stuff on occasion, but this time, it seems fine..

[Tahaan]

Ah yes. That's why I need a calculator with a built in materials database.