When installing engineered lumber joists (I-joists) in California residential construction, what is the primary code requirement for web stiffeners?
Correct Answer
A) Web stiffeners are required at all bearing points and concentrated loads
Per CRC Section R502.8.2 and manufacturer requirements referenced in the code, engineered lumber I-joists must have web stiffeners installed at all bearing points and locations of concentrated loads to prevent web crippling. This is critical for maintaining the structural integrity of the engineered lumber system.
Why This Is the Correct Answer
Web stiffeners are mandatory at all bearing points and concentrated loads for I-joists per CRC Section R502.8.2. These stiffeners prevent web crippling and buckling of the thin web material under point loads. Without proper stiffening, the engineered lumber web can fail catastrophically at support points, compromising structural integrity. This requirement applies regardless of span length and is critical for safe installation of engineered lumber systems in residential construction.
Why the Other Options Are Wrong
Option B: Web stiffeners are only required at the center span
Center span stiffening alone is insufficient and not the primary code requirement. I-joists are most vulnerable to web failure at bearing points where concentrated loads transfer through the thin web material. The center span typically experiences distributed loads that the web can handle without additional stiffening, making this option inadequate for structural safety.
Option C: Web stiffeners are only required for spans exceeding 20 feet
Web stiffener requirements are not based on span length but on load concentration points. Even short-span I-joists require stiffeners at bearing points to prevent web crippling. The 20-foot threshold is arbitrary and not found in building codes. Load magnitude and concentration, not span distance, determines stiffener necessity.
Option D: Web stiffeners are not required for residential applications
This is completely incorrect as residential applications absolutely require web stiffeners. CRC Section R502.8.2 specifically addresses residential I-joist installations and mandates stiffeners at bearing points. Residential loads can be just as concentrated and damaging to unstiffened webs as commercial applications, making this requirement essential for safety.
Memory Technique
Remember 'BEAR the LOAD' - Bearing points and concentrated LOADs always need stiffeners to prevent the web from tearing like paper under pressure.
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