Structural Mechanics
- Deflection Analysis Live load: L/360-L/480. Dead load: L/240. Total load: L/240-L/360. Creep factor: 1.5-2.0. Dynamic amplification: 1.15-1.30.
- Load Distribution Point load: 300-1000 lbs. Uniform load: 40-100 psf. Impact factor: 1.15-1.25. Load sharing: 40-60%. System factor: 1.1-1.3.
- Material Response Elastic modulus: 1.2-2.0×10⁶ psi. Shear modulus: 0.5-0.7×10⁶ psi. Poisson's ratio: 0.3-0.4. Yield stress: 1100-3000 psi.
Design Parameters
- Section Properties Moment of inertia: 50-300 in⁴. Section modulus: 10-50 in³. Radius of gyration: 2-4". Area moment: 5-15 in⁴. Torsional constant: 2-8 in⁴.
- Support Conditions Bearing length: 1.5-3.5". End fixity: 0-100%. Lateral restraint: 4-8 ft. Bridging interval: 6-8 ft. Support width: 3.5-5.5".
- System Integration Composite action: 0-75%. Load sharing: 3-5 joists. Diaphragm effect: 10-30%. Connection efficiency: 80-95%. System factor: 1.1-1.3.
Performance Criteria
- Serviceability Limits Vibration frequency: 8-15 Hz. Acceleration limit: 0.5%g. Damping ratio: 3-7%. First mode: 14-18 Hz. Human sensitivity: ISO 2631.
- Durability Factors Moisture content: 12-19%. Creep coefficient: 1.5-2.0. Fatigue life: 10⁶ cycles. Environmental factor: 0.8-1.0. Service class: 1-2.
- Safety Margins Ultimate/service ratio: 2.5-3.0. Stability factor: 1.5-2.0. Load duration: 0.6-1.0. Temperature effect: 0.9-1.1. System reliability: 3-4σ.
Construction Standards
- Installation Requirements Crown orientation: ±1/8". Spacing tolerance: ±1/16". Level alignment: ±1/4". Bearing surface: 90±1°. Hardware torque: 30-50 ft·lbs.
- Connection Details Nailing pattern: 2-3 rows. Bolt diameter: 1/2-3/4". Washer size: 3D min. Edge distance: 4D min. Joist hanger capacity: 1.5× load.
- Quality Control Inspection points: 5-7. Moisture testing: pre-install. Deflection monitoring: 30-90 days. Documentation: as-built ±1/8". Load test: 1.5× design.