Structural Design
- Load Analysis Dead load: 10-20 psf. Live load: 40-100 psf. Impact factor: 1.15-1.25. Load duration: 0.6-1.0. Safety factor: 2.0-2.5.
- Member Properties Section modulus: 10-50 in³. Moment of inertia: 50-300 in⁴. Shear capacity: 100-300 lbs/in². Bearing area: 3-6 in². Depth/width ratio: 2-3.
- Strength Limits Bending stress: 1000-2000 psi. Shear stress: 150-300 psi. Compression ⊥: 400-625 psi. Tension ∥: 650-1100 psi. Modulus of rupture: 2400-3000 psi.
Material Engineering
- Wood Properties Specific gravity: 0.42-0.55. Moisture content: 12-19%. Elastic modulus: 1.2-2.0×10⁶ psi. Shear modulus: 0.5-0.7×10⁶ psi. Poisson's ratio: 0.3-0.4.
- Engineered Products I-joist depth: 9.5-24". Flange area: 1.5-5.0 in². Web thickness: 3/8". LVL grade: 2.0E-2.3E. OSB rating: 24/16-48/24.
- Treatment Requirements Preservative retention: 0.25-0.60 pcf. Penetration: 0.4-0.75". Fire rating: 1-2 hr. Decay resistance: Class 1-3. Insect protection: Type A-C.
Installation Guidelines
- Assembly Details Bearing length: 1.5-3.5". End distance: 2-4". Fastener spacing: 6-12". Bridging interval: 6-8 ft. Crown orientation: up ±1/8".
- Support Conditions Wall plate width: 3.5-5.5". Rim joist depth: ±1/16". Hanger clearance: 1/8". Blocking height: full depth. Cantilever ratio: 1:3-1:4.
- Connection Specifications Nail size: 10d-16d. Bolt diameter: 1/2-3/4". Washer size: 3D min. Edge distance: 4D min. Withdrawal strength: 100-300 lbs/in.
Performance Verification
- Quality Control Straightness: ±1/4"/10ft. Twist: 1°/ft max. Wane: 25% max. Splits: 1/4 depth. Knot ratio: WWPA rules.
- Testing Requirements Load verification: 1.5× design. Deflection check: L/360-L/480. Moisture reading: pre-install. Grade stamp: visible. Documentation: as-built ±1/8".
- Maintenance Protocols Inspection interval: annual. Moisture monitoring: quarterly. Hardware check: 2-3 years. Treatment renewal: 5-7 years. Structural review: 10 years.