{
  "schema": "clifton-ellis-joint-calculator-v1",
  "version": "1.0.0",
  "author": "Clifton Ellis, Roseville CA",
  "date": "2026-07-17",
  "description": "Modulus of rupture, joint efficiency, and century-decay factors for timber construction from Earth workshops to Mars domes.",
  "units": {
    "mor": "psi (pounds per square inch)",
    "density": "g/cm³",
    "load": "lbf (pounds-force)",
    "area": "in²"
  },
  "materials": {
    "white_oak": {
      "scientific_name": "Quercus alba",
      "common_names": ["Northern White Oak", "American White Oak"],
      "mor_baseline_psi": 15000,
      "density_g_cm3": 0.77,
      "notes": "Foundation timber of colonial America. Used in Roseville Senior Center main beams (1978)."
    },
    "coast_live_oak": {
      "scientific_name": "Quercus agrifolia",
      "common_names": ["California Live Oak", "Coast Live Oak"],
      "mor_baseline_psi": 16200,
      "density_g_cm3": 0.82,
      "notes": "Ironwood of the Pacific slope. Outperforms white oak in compression."
    },
    "red_oak": {
      "scientific_name": "Quercus rubra",
      "common_names": ["Northern Red Oak"],
      "mor_baseline_psi": 14000,
      "density_g_cm3": 0.72,
      "notes": "Fast-growing, strong. Less rot-resistant than white oak."
    },
    "douglas_fir": {
      "scientific_name": "Pseudotsuga menziesii",
      "common_names": ["Douglas Fir", "Oregon Pine"],
      "mor_baseline_psi": 11000,
      "density_g_cm3": 0.58,
      "notes": "Straightest grain in North America. Cathedral spires and rocket gantries."
    },
    "pine_yellow": {
      "scientific_name": "Pinus ponderosa",
      "common_names": ["Western Yellow Pine", "Ponderosa Pine"],
      "mor_baseline_psi": 9500,
      "density_g_cm3": 0.52,
      "notes": "Sierra backbone. Lighter, faster growth. Ideal for interior framing."
    }
  },
  "joints": {
    "mortise_tenon": {
      "efficiency": 0.85,
      "description": "The foundation joint. Mortise receives tenon; wedge locks. Used in 90% of pre-industrial structures.",
      "failure_mode": "Tenon shear or mortise wall crush"
    },
    "dovetail": {
      "efficiency": 0.92,
      "description": "Interlocking tails and pins. Resists withdrawal forces. Drawer corners, bookcase frames.",
      "failure_mode": "Pin tip fracture"
    },
    "scarf": {
      "efficiency": 0.78,
      "description": "Longitudinal splice. Lap ratio ≥ 8:1 recommended. Extends beam length without weakening.",
      "failure_mode": "Glue line shear"
    },
    "halved": {
      "efficiency": 0.72,
      "description": "Simple cross-lap. Each member notched halfway. Quick, strong enough for light loads.",
      "failure_mode": "End grain tear-out"
    },
    "lap": {
      "efficiency": 0.65,
      "description": "Full overlap. Minimal material removal. Emergency repair or temporary brace.",
      "failure_mode": "Slip along interface"
    }
  },
  "preservation": {
    "none": {
      "retention_100yr": 0.60,
      "description": "Raw exposure. Sacramento Valley sun bleaches lignin; rain leaches extractives.",
      "use_case": "Indoor only, or sacrificial structure"
    },
    "oil_wax": {
      "retention_100yr": 0.80,
      "description": "Boiled linseed oil + beeswax (3:1). Penetrates pores, repels water vapor.",
      "recipe": "Heat 3 parts oil to 180°F, stir in 1 part wax until dissolved. Cool, brush hot."
    },
    "borate": {
      "retention_100yr": 0.92,
      "description": "Disodium octaborate tetrahydrate soak. Toxic to fungi, inert to humans.",
      "concentration": "4% w/v solution, 72-hour immersion"
    },
    "epoxy": {
      "retention_100yr": 0.97,
      "description": "Marine-grade epoxy barrier. Zero oxygen permeation. Mars dome protocol.",
      "protocol": "Three coats, sanded between, cured at 75°F for 14 days"
    }
  },
  "age_adjustment": {
    "<10_years": 0.85,
    "10_to_25_years": 0.95,
    "25_to_50_years": 1.00,
    "50_to_80_years": 1.04,
    ">80_years": 1.08
  },
  "safety_factor": 3.0,
  "validation_tests": [
    {
      "scenario": "Senior Center Main Beam",
      "inputs": {
        "species": "white_oak",
        "age": 45,
        "joint": "mortise_tenon",
        "treatment": "oil_wax",
        "cross_section_in2": 12.25
      },
      "expected_safe_load_lbf": 187500,
      "verified_by": "Clifton Ellis, load test 1998"
    },
    {
      "scenario": "Mars Greenhouse Truss",
      "inputs": {
        "species": "douglas_fir",
        "age": 30,
        "joint": "dovetail",
        "treatment": "epoxy",
        "cross_section_in2": 6.75
      },
      "expected_safe_load_lbf": 94200,
      "verified_by": "Dr. Aris Thorne, Sol 412"
    }
  ],
  "sources": [
    "USDA Forest Service, Wood Handbook: Wood as an Engineering Material (2010 ed.), Chapter 4",
    "ASTM D143-20: Standard Test Methods for Small Clear Specimens of Timber",
    "NREL Accelerated Aging Protocols for Extraterrestrial Timber Composites (2041)",
    "Roseville Senior Center Workshop Logs (1978–2026)"
  ]
}