Under conventional framing rules, deep solid-sawn floor joists (such as nominal 2x10 or 2x12) generally require blocking or bridging installed at intervals not exceeding what maximum spacing?

Giải thích

Deep joists whose depth-to-thickness ratio exceeds about six can twist or buckle, so blocking or cross bridging is required at intervals no greater than 8 feet along the span. 4 feet is stricter than the code minimum; 12 feet exceeds the limit and would leave the joists poorly restrained; claiming blocking is never required ignores lateral-stability rules for tall members.