Add structural calculation worksheets

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

concrete-beam/test_concrete_beam.py

@@ -0,0 +1,46 @@
+from pathlib import Path
+import importlib.util
+
+import pytest
+
+
+HERE = Path(__file__).resolve().parent
+
+spec = importlib.util.spec_from_file_location("concrete_beam_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
+
+
+@pytest.fixture
+def result():
+    import yaml
+
+    with (HERE / "input.yaml").open(encoding="utf-8") as handle:
+        return compute(yaml.safe_load(handle))
+
+
+def test_example_demands(result):
+    v = result["values"]
+    assert v["self_weight_klf"] == pytest.approx(0.1)
+    assert v["wu_klf"] == pytest.approx(0.7325)
+    assert v["Mu_kipft"] == pytest.approx(23.44)
+    assert v["Vu_kip"] == pytest.approx(5.86)
+
+
+def test_example_flexure(result):
+    v = result["values"]
+    assert v["a_in"] == pytest.approx(1.823529, rel=1e-5)
+    assert v["et"] == pytest.approx(0.010283, rel=1e-3)
+    assert v["phi"] == pytest.approx(0.9)
+    assert v["phiMn_kipft"] == pytest.approx(23.961176, rel=1e-5)
+    assert result["checks"]["flexure"]["ok"] is True
+
+
+def test_example_min_steel_and_shear(result):
+    v = result["values"]
+    assert v["As_min_in2"] == pytest.approx(0.253333, rel=1e-4)
+    assert v["phiVc_kip"] == pytest.approx(6.244016, rel=1e-4)
+    assert result["checks"]["minimum_steel"]["ok"] is True
+    assert result["checks"]["shear"]["ok"] is True