check_flexure returns UnsupportedSection with the reason "web is not compact; SNI 1729 clauses F4/F5 are not implemented".
Refusing is the right behaviour and should stay. But it means a whole class of real sections cannot be checked at all: built-up plate girders, and slender-web sections generally.
Scope
- F4, other I-shaped members with compact or non-compact webs bent about their major axis
- F5, doubly and singly symmetric I-shaped members with slender webs
- The web plastification factor
Rpc and the bending strength reduction factor Rpg
Why it is worth doing rather than leaving as a refusal
The refusal is honest, but a plate girder is exactly the case where someone reaches for a library instead of a spreadsheet, because the arithmetic is long enough to get wrong by hand.
Not in scope here
Tension field action. That deserves its own issue and belongs with the shear module.
Tests
Same standard as the rest of the crate: worked examples with the hand calculation in a comment, plus a boundary case sitting exactly at the compact/non-compact web limit, since that is where an off-by-one in the branch would hide.
check_flexurereturnsUnsupportedSectionwith the reason "web is not compact; SNI 1729 clauses F4/F5 are not implemented".Refusing is the right behaviour and should stay. But it means a whole class of real sections cannot be checked at all: built-up plate girders, and slender-web sections generally.
Scope
Rpcand the bending strength reduction factorRpgWhy it is worth doing rather than leaving as a refusal
The refusal is honest, but a plate girder is exactly the case where someone reaches for a library instead of a spreadsheet, because the arithmetic is long enough to get wrong by hand.
Not in scope here
Tension field action. That deserves its own issue and belongs with the shear module.
Tests
Same standard as the rest of the crate: worked examples with the hand calculation in a comment, plus a boundary case sitting exactly at the compact/non-compact web limit, since that is where an off-by-one in the branch would hide.