---
name: reference-kds-24-14-21
description: STANDING RULE — KDS 24 14 21 (콘크리트교 설계기준, 한계상태설계법) is the base design standard for ALL projects; where the document/extracted text live, key numbers, and how deviations are reported
metadata:
  type: reference
---

User rule (2026-10-06): "모든 프로젝트에서 KDS 24 14 21 콘크리트교 설계기준(한계상태설계법)이 기본 원칙. 이거랑 다르게 배근된 철근이 있다면 철근재료표 비고란에 다른 색상으로 적고 저장". Also written into `D:\Rhino-MCP\rhino-mcp-main\CLAUDE.md` §0.

- Source: `D:\★Pier 자료\KDS 24 14 21 콘크리트교 설계기준(한계상태설계법).hwp` (2025.08.22 개정, HWP5 binary, Hancom Office 2018 is installed but not needed).
- Readable text incl. equations: `D:\Rhino-MCP\rhino-mcp-main\rebar_pipeline\kds\KDS_24_14_21.txt` made by `kds\hwp2txt.js` (own OLE/zlib parser, `node hwp2txt.js in.hwp out.txt`). Equations appear as `[수식: …]` lines right after their paragraph. Key sections by line: 4.4.4 cover, 4.5.2.1 bends (table 4.5-1), 4.5.3.1 spacing, 4.5.4.2 hooks, 4.5.5 laps, 4.6.2.6 shear, 4.6.2.8 skin, 4.6.15 temperature (re-grep, line numbers shift).
- Numbers verified: min inner bend diameter D16↓ 2db, D19↑ 3.5db; horizontal clear spacing ≥ max(1.5db, 1.5Gmax, 40); multi-layer vertical clear ≥ max(25, db) same vertical plane; hook 90–150° extension ≥ 5db; shear s_long ≤ 0.75d(1+cotα), s_trans ≤ min(0.75d, 600), ρv,min = 0.08√fck/fy; lap lateral clear ≤ 4db/50; cover = max(c_bond=db, c_dur table 4.4-4: E0 20 … ED3/ES3 55) + Δc_dev 10; cover > 70 → skin reinforcement 0.005 A_ct,ext (4.6.2.8(4)). Lap length formula (4.5-8) needs σsd/fbd from design → NOT verified.
- Reporting: deviations go to the material-table DXF as column "비고 3 (KDS 24 14 21 기준 상이)" in magenta (62=6, layer KDS) via `rebar_pipeline\dxf\kds_note_column.ps1` (needs a UTF-8 BOM when saved; CP949 can't hold ⊔ so write "U형").
- 대호지교 P1 result 2026-10-06 (`261006_철근재료표_KDS.dxf`): satisfied = bend radii for ALL marks (inner R: C1/C2/C3/C8/C10 76.2, C26 57.3, C19/C21/C23/C25 31.8, hooks C20/22/24 52, C12–C18 all boxes/leaves centerline R=66.6 → inner 55.5, verified by length inversion); NOTE an earlier "C15 width-1005 inner R 34.6 < 38.85" finding was a MEASUREMENT ARTIFACT of the isocurve-curvature method — never trust it; hooks c=100 ≥ 5db=79.5; stirrup spacing & ρv; cover. Deviations noted: stirrups C12–C18 on main-bar centerlines (clear spacing <0) and coaxial lap legs; C19/C21/C23 hoops & C25 legs at w=±1630 on stirrup outer legs; C26 at stirrup lid-top height and legs crossing C4–C7; coaxial lap modelling of C1/C2/C3/C8/C10 ends. Clash-type rows are based on the 2026-10-02 clash check (not re-run after 10-06 edits).
Related: [[feedback-kds-rebar-bend-radius]], [[project-p1-final-model-state-261006]], [[feedback-material-table-text-alignment]], [[reference-rebar-pipeline-scripts]].

**Measuring bend radius — lesson (2026-10-06):** do NOT estimate bend radius from min curvature of pipe-surface isocurves (gave a false 34.6 for C15 1005 base; real R=66.6). Use length inversion: polyline S→C1→C2→E from the two end-circle centers + corner z (bbox ± bar radius), then R = (L_poly − L_centerline)/(2·(2−π/2)) with L_centerline = (area − caps)/(2πr). Verified identical R=66.6 on every box leaf.