A15. Settlement Layout Details Stage

Note: CLS doesn’t force one shape—it scores the essentials no matter the geometry.

Classic CLS implied designs by settlement horizon:

Stage 0-2 = IL-0 to IL-2 (Scout/Beachhead/Foothold): a spine with 1–2 mini-loops scores fastest to build and easiest to service. Rough-in cross-links and dual-loop utilities now.

Stage 3-5 = IL-3 to IL-5 (Village/Town/City): ring + radials (ideally dual-ring) balances resilience and flow. Add a service boulevard or bridged cuts for inner access.

Stage 5-7 = IL-5 to IL-7 (City/Regional/Country): a mesh with a service-alley lattice provides graceful degradation and industrial capacity. Sector into districts; keep reserves for renewal.

Classic design elements table due to CLS for IL-0 → IL-7. Numbers are indicative design targets so you can sanity-check proposals at a glance.

CLS applicability: Full CLS hard-gates kick in ≥10,000 m² (typically IL-3+). For IL-0..2, you can still compute a provisional CLS to compare layouts.

Heavy-access bias: Spine/early rings are naturally strong here; for rings/meshes, plan service boulevards/alleys early to avoid buried/bridged penalties later.

Growth path: Spine → close two cross-links → first ring → add second ring + cross-ties + boulevard → mesh → district sectoring → mesh-of-meshes.

Stage 0 = IL-0 · Scout Hub — “Stand it up, keep it reachable”

Topology: short spine with 1–2 branches; all gear face the perimeter
CLS target: 58–62 (don’t chase higher yet)

Safety & Resilience: 2 havens on the spine; compartment target 800–1,000 m²; largest ≤ 1,500 m².

Flow: simple OD; keep egress ≤ 60 s everywhere via two routes (short cross-spur if needed).

Plan & Envelope: link density 18–24 m / 1,000 m²; straight runs; avoid curves.

Mass: joints/node ~2.0–2.4; bends/100 m under caps; curved fraction ≤0.10.

Construction & Maintenance: heavy-access ≥0.95 coverage; median drive ≤ 120–150 m; isolation valves ≤ 30 m spacing.

Expandability: leave capped stubs every 60–90 m.

Habitability: shield HAB/MED first; one commons on the spine.

Env & Energy: single utility loop is OK, but route space for a counter-loop.
Upgrade hooks: rough-in two cross-links that can close into a first loop later.

Stage 1 = IL-1 · Beachhead Hub — “Stabilize and codify”

Topology: spine + mini-loops (close a small loop around med/galley/admin)
CLS target: 60–66

Safety: 3 havens; keep compartments ~1,000–1,200 m²; set clean↔dirty bulkhead at garage/workshop.

Flow: F1/F2 ≥ 0.6; bulkhead crossings ~0.2–0.4/trip.

Plan/Mass: stay near the link-density sweet spot; keep 4-ways rare.

C&M: standardize ≤6 link SKUs; service clear both sides of spine.

Expandability: mark future ring tie-points; dual-use cross-links for people & utilities.

Upgrade hooks: pre-install sectionalizers, spare risers, and door frames sized to upgrade to bulkheads.

Stage 2 = IL-2 · Foothold Hub — “Foothold with discipline”

Topology: spine with two cross-links complete (loop-ready)
CLS target: 62–68

Safety: 3–4 havens; verify two edge-disjoint routes to a haven from all nodes ≤ 60 s.

Pressure zoning: density near 1 compartment / 1,000–1,500 m²; still cap ≤ 1,500 m².

Flow: add a second cross-link if the spine saturates; keep spokes short.

C&M: heavy-access ≥0.9; median drive ≤ 150 m; junction alcoves at all T’s.

Env/Energy: start counter-rotating utility trunk on parts of the loop; aim ≥60–70% nodes dual-fed.

Upgrade hooks: close the first full ring when crew/time allow.

Stage 3 = IL-3 · Village Hub — “Close the loop”

Topology: Ring + Radials (first full loop)
CLS target: 70–74

Safety: 3–4 havens spaced around ring; sector bulkheads make compartments 1,200–1,500 m².

Flow: short spokes; add one inner mini-loop around high-use cluster to cut hub loads.

Plan: link density 22–28 m / 1,000 m²; avoid over-spoking.

Mass: prefer T-junctions; curved fraction ≤0.08.

C&M: heavy-access dips unless planned—add bridged cuts or a service boulevard to reach inner side; median drive ≤ 180 m.

Expandability: many outer-ring attach faces; live expansion on at least half.

Env/Energy: dual utility loop with cross-ties; N2 ≥ 0.7.

Upgrade hooks: reserve corridors for second ring segments and orthogonal cross-ties (mesh seeds).

Stage 4 = IL-4 · Town Hub — “Dual ring + service boulevard”

Topology: dual ring with cross-ties; planned service boulevard
CLS target: 74–78

Safety: 4–5 havens; robust sectoring; test single-edge failure drills.

Flow: cross-ties every ~120 m; keep F2 ≤ 0.8 utilization at peaks.

Plan: link density 24–30; grid adherence helpful (≤10% shim).

Mass: cap 4-ways at ≤0.1 / 100 m; limit underpasses (prefer bridges).

C&M: heavy-access ≥0.85; barrier-crossing burden near 0.3; isolation spacing ≤30 m.

Expandability: outer ring becomes your growth manifold.

Env/Energy: dual-loop everywhere; critical nodes tri-fed where feasible.

Upgrade hooks: lay service-alley spines across the interior every 2–3 blocks; set pads for future industry bays.

Stage 5 = IL-5 · City Hub — “Mesh the city”

Topology: Mesh (rect or hex) + service-alley lattice (every 2–3 cells)
CLS target: 80–85

Safety: 5–7 havens; algebraic connectivity high; maintain S1/S2 ≥ 0.9.

Flow: OD times short; two disjoint routes common; bulkhead crossings ~0.3–0.4/trip.

Plan: link density 24–32; long straights; disciplined junctions.

Mass: bends/100 m at or below caps; curved fraction ≤0.05; bridges ≫ underpasses.

C&M: heavy-access ≥0.9, median drive ≤ 150 m; junction alcoves standard; SKU set locked (≤6 node, ≤6 link).

Expandability: high attach density; low reconfig cost (bays swap uses).

Env/Energy: dual/tri-loop utilities; independent HVAC zones for hot uses.

Upgrade hooks: dedicate corridors for redundant pipe/electrical replacements; pre-permit extra alleys.

Stage 6 = IL-6 · Regional Hub — “Mesh of meshes; isolate by sector”

Topology: Hierarchical mesh (districts as sectors) with perimeter service boulevard
CLS target: 85–90

Safety: haven per 3–5k m²; district bulkheads; maintain egress ≤ 60 s under single edge OR node failure.

Flow: cross-district ties sized for peak logistics; keep chokepoints rare.

Plan/Mass: maintain link density band while adding districts; keep 4-ways scarce.

C&M: heavy-access ≥0.9; median drive ≤ 130–150 m; alley lattice continuous; civil works penalties low.

Expandability: modular district add-ons; live expansion on ≥ 80% faces.

Env/Energy: tri-loop for criticals; district microgrids with sectionalizers; independent HVAC loops by district.
Upgrade hooks: reserve quarantine corridors, independent utility galleries between districts, and sites for rebuild cycles.

Stage 7 = IL-7 · Country Hub — “City-state fabric; long-life ops”

Topology: Networked districts (mesh-of-meshes) with redundant service boulevards and protected utility galleries
CLS target: 88–92+

Safety: many havens (8–12); overlapping refuge networks; periodic rebuild lanes that don’t break S1/S2.

Flow: commuter & logistics axes separated; path diversity everywhere (F3 ≥ 0.9).

Plan: disciplined grid; service alleys touch all interior blocks; envelope remains compact.

Mass: standardization locked; repair-friendly straight runs; minimal underpasses.

C&M: heavy-access ≥0.95; isolation spacing ≤25 m; by-pass & test ports at every bulkhead.

Expandability: rolling renewal—take a district offline while others maintain CLS targets.

Env/Energy: tri-loop plus emergency low-pressure loop; independent district microgrids; thermal zoning strict.
Long-life hooks: built-in “replacement corridors,” spare-volume galleries, and policy that maintains CLS under dark-Earth drills.