Add structural calculation worksheets

Collection of engineering calculation projects (Python + Typst), each with
input, calc script, tests, results, and generated PDF where available.

wood-joist/test_wood_joist.py

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+from pathlib import Path
+import importlib.util
+import json
+import subprocess
+import sys
+
+import pytest
+import yaml
+
+HERE = Path(__file__).resolve().parent
+spec = importlib.util.spec_from_file_location("wood_joist_calc", HERE / "calc.py")
+assert spec is not None and spec.loader is not None
+calc_module = importlib.util.module_from_spec(spec)
+spec.loader.exec_module(calc_module)
+compute = calc_module.compute
+
+
+def load_input():
+    with (HERE / "input.yaml").open(encoding="utf-8") as handle:
+        return yaml.safe_load(handle)
+
+
+@pytest.fixture
+def result():
+    return compute(load_input())
+
+
+def test_example_loads_and_section(result):
+    v = result["values"]
+    assert v["w_plf"] == pytest.approx(975)
+    assert v["wL_plf"] == pytest.approx(650)
+    assert v["A_in2"] == pytest.approx(33.25)
+    assert v["Ix_in4"] == pytest.approx(250.1, abs=0.1)
+    assert v["Sx_in3"] == pytest.approx(52.6, abs=0.1)
+
+
+def test_example_demands(result):
+    v = result["values"]
+    assert v["M_ftlbf"] == pytest.approx(9871.88, abs=0.01)
+    assert v["V_lbf"] == pytest.approx(4387.5)
+    assert v["R_lbf"] == pytest.approx(4387.5)
+
+
+def test_example_flexure(result):
+    v = result["values"]
+    assert v["RB"] == pytest.approx(0.881, abs=0.001)
+    assert v["Fb_star_psi"] == pytest.approx(2400)
+    assert v["FbE_psi"] == pytest.approx(789157.9, rel=1e-3)
+    assert v["CL"] == pytest.approx(0.9998, abs=0.001)
+    assert v["Fb_prime_psi"] == pytest.approx(2399.6, abs=0.2)
+    assert v["fb_psi"] == pytest.approx(2250.2, abs=0.1)
+    assert v["Ma_ftlbf"] == pytest.approx(10527.6, abs=0.3)
+    assert v["fb_psi"] / v["Fb_prime_psi"] == pytest.approx(0.938, abs=0.001)
+    assert result["checks"]["flexure"]["ok"] is True
+
+
+def test_example_shear(result):
+    v = result["values"]
+    assert v["Fv_prime_psi"] == pytest.approx(300)
+    assert v["fv_psi"] == pytest.approx(197.932, abs=0.001)
+    assert v["fv_psi"] / v["Fv_prime_psi"] == pytest.approx(0.66, abs=0.005)
+    assert result["checks"]["shear"]["ok"] is True
+
+
+def test_example_bearing(result):
+    v = result["values"]
+    assert v["bed_in"] == pytest.approx(3)
+    assert v["Cb"] == pytest.approx(1.15)
+    assert v["Fcp_prime_psi"] == pytest.approx(649.75, abs=0.01)
+    assert v["Ab_in2"] == pytest.approx(8.75)
+    assert v["fcp_psi"] == pytest.approx(501.429, abs=0.001)
+    assert v["fcp_psi"] / v["Fcp_prime_psi"] == pytest.approx(0.772, abs=0.001)
+    assert result["checks"]["bearing"]["ok"] is True
+
+
+def test_example_deflection(result):
+    v = result["values"]
+    assert v["delta_total_in"] == pytest.approx(0.339, abs=0.001)
+    assert v["delta_live_in"] == pytest.approx(0.226, abs=0.001)
+    assert v["delta_allow_total_in"] == pytest.approx(0.45)
+    assert v["delta_allow_live_in"] == pytest.approx(0.30)
+    assert result["checks"]["deflection_total"]["ok"] is True
+    assert result["checks"]["deflection_live"]["ok"] is True
+
+
+def test_all_checks_pass(result):
+    assert all(result["checks"][name]["ok"] for name in ("flexure", "shear", "bearing", "deflection_total", "deflection_live")) is True
+
+
+def test_alternate_units_match_default(result):
+    alt = load_input()
+    alt.update({
+        "span": "108 in",
+        "width": "3.5 in",
+        "depth": "9.5 in",
+        "M": "118462.5 lbf * in",
+        "V": "4387.5 lbf",
+        "R": "4387.5 lbf",
+    })
+    converted = compute(alt)
+    for key in ("span_ft", "M_ftlbf", "V_lbf", "R_lbf", "fb_psi", "delta_total_in"):
+        assert converted["values"][key] == pytest.approx(result["values"][key], rel=1e-6)
+
+
+def test_wrong_dimension_is_rejected():
+    bad = load_input()
+    bad["span"] = "9 kip"
+    with pytest.raises(ValueError, match="span"):
+        compute(bad)
+
+
+def test_rb_limit_enforced():
+    bad = load_input()
+    bad["unbraced_length"] = "4000 in"
+    with pytest.raises(ValueError, match="50"):
+        compute(bad)
+
+
+def test_cl_bounds_enforced():
+    bad = load_input()
+    # A very large E_min drives the beam stability factor to 0 (catastrophic
+    # cancellation in the C_L equation), which is out of the valid (0, 1] range.
+    bad["E_min"] = "1e100 psi"
+    with pytest.raises(ValueError, match="CL"):
+        compute(bad)
+
+
+def test_bearing_length_limit_enforced():
+    bad = load_input()
+    bad["bearing_length"] = "6 in"
+    with pytest.raises(ValueError, match="6"):
+        compute(bad)
+
+
+def test_bearing_end_distance_enforced():
+    bad = load_input()
+    bad["bearing_end_distance"] = "2.5 in"
+    with pytest.raises(ValueError, match="3"):
+        compute(bad)
+
+
+def test_typst_compiles_and_presents_python_numbers(result):
+    subprocess.run([sys.executable, str(HERE / "calc.py")], check=True, cwd=HERE.parents[1])
+    pdf = HERE / "generated" / "wood-joist.pdf"
+    subprocess.run(
+        ["typst", "compile", "--root", ".", "calcs/wood-joist/wood-joist.typ", str(pdf)],
+        check=True, cwd=HERE.parents[1],
+    )
+    assert pdf.exists()
+    query = subprocess.run(
+        ["typst", "eval", "query(<wood-joist-results>)", "--root", ".",
+         "--in", "calcs/wood-joist/wood-joist.typ", "--format", "json"],
+        check=True, capture_output=True, text=True, cwd=HERE.parents[1],
+    )
+    published = json.loads(query.stdout)
+    assert len(published) == 1
+    meta = published[0]["value"]
+    values = result["values"]
+    assert meta["flexure_util"] == pytest.approx(values["fb_psi"] / values["Fb_prime_psi"], abs=0.001)
+    assert meta["shear_util"] == pytest.approx(values["fv_psi"] / values["Fv_prime_psi"], abs=0.001)
+    assert meta["bearing_util"] == pytest.approx(values["fcp_psi"] / values["Fcp_prime_psi"], abs=0.001)
+    assert meta["delta_total_in"] == pytest.approx(values["delta_total_in"], abs=1e-6)
+    assert meta["delta_live_in"] == pytest.approx(values["delta_live_in"], abs=1e-6)
+
+
+def test_typst_load_demands_match_checked_inputs(result):
+    subprocess.run([sys.executable, str(HERE / "calc.py")], check=True, cwd=HERE.parents[1])
+    query = subprocess.run(
+        ["typst", "eval", "query(<wood-joist-loads>)", "--root", ".",
+         "--in", "calcs/wood-joist/wood-joist.typ", "--format", "json"],
+        check=True, capture_output=True, text=True, cwd=HERE.parents[1],
+    )
+    published = json.loads(query.stdout)
+    assert len(published) == 1
+    derived = published[0]["value"]
+    values = result["values"]
+    assert derived["w_plf"] == pytest.approx(values["w_plf"], abs=0.001)
+    assert derived["wL_plf"] == pytest.approx(values["wL_plf"], abs=0.001)
+    assert derived["M_ftlbf"] == pytest.approx(values["M_ftlbf"], abs=0.01)
+    assert derived["V_lbf"] == pytest.approx(values["V_lbf"], abs=0.001)
+    assert derived["R_lbf"] == pytest.approx(values["R_lbf"], abs=0.001)