--- name: concrete-slab-design description: "This skill should be used when an architect or structural designer needs to verify PDF-backed concrete slab requirements such as minimum slab thickness, minimum flexural reinforcement, and shrinkage/temperature reinforcement rules in Taiwan's concrete structure design code." user-invocable: true license: CC-BY-SA-4.0 compatibility: claude-code,opencode,agent-skills metadata: audience: architects region: taiwan class: C regulation: 建築物混凝土結構設計規範 --- # Concrete Slab Design ## Overview Design requirements for reinforced concrete slabs in Taiwan, limited here to items directly verified against the uploaded PDF: minimum slab thickness, minimum flexural steel, and shrinkage/temperature reinforcement rules. Slab-step, opening, and splice details are preserved only as chapter references unless directly transcribed from the source. For cover and splice fundamentals, see [concrete-general-requirements](../../混凝土通用規定/concrete-general-requirements/). --- ## Section 1: Code Navigation | Topic | Governing Clause | |---|---| | One-way slab minimum thickness | 7.3.1.1 | | One-way slab minimum flexural steel | 7.6.1.1 | | One-way shrinkage and temperature steel | 7.6.4, 7.7.6 | | Two-way slab minimum thickness | 8.3.1.1 | | Slab cover | 20.5.1.3.1 | Structural classification between one-way and two-way slab systems should follow the designer's analysis model and the applicable chapter, rather than an unverified shorthand rule. --- ## Section 2: Minimum Slab Thickness ### 2.1 One-Way Slab Minimum Thickness (Deflection Control) For non-prestressed one-way slabs with fy = 420 MPa: | Support Condition | Minimum h | |---|---| | Simply supported | L/20 | | One end continuous | L/24 | | Both ends continuous | L/28 | | Cantilever | L/10 | > Multiply by (0.4 + fy/700) for fy ≠ 420 MPa. L = clear span length. Source: 7.3.1.1, Table 7.3.1.1, 7.3.1.1.1. ### 2.2 Two-Way Slab Minimum Thickness For non-prestressed two-way slabs, the minimum thickness depends on panel position and column head condition. | Condition | fy = 420 MPa | |---|---| | No column head, outer panel, no edge beam | ln/30 | | No column head, outer panel, with edge beam | ln/33 | | No column head, inner panel | ln/33 | | With column head, outer panel | ln/36 | | With column head, inner panel | ln/36 | Minimum absolute thickness: - No column head: 125 mm - With column head: 100 mm Source: 8.3.1.1, Table 8.3.1.1. ### 2.3 Practical Minimum for Fire Resistance Fire-resistance thickness may be governed by 建築技術規則 rather than slab-structure clauses alone. This skill does not restate fire-thickness numbers not transcribed from the governing fire code. --- ## Section 3: Flexural Reinforcement ### 3.1 Minimum Flexural Reinforcement For non-prestressed slabs, minimum flexural steel is: $$A_{s,min} = 0.0018A_g$$ This is the same base ratio used for slab shrinkage and temperature reinforcement. Source: 7.6.1.1. ### 3.2 Maximum Bar Spacing Maximum bar spacing for slab flexural reinforcement: - Critical sections: min(3h, 450 mm) - Other sections: min(3h, 450 mm) Where h = total slab thickness. --- ## Section 4: Temperature and Shrinkage Reinforcement (溫度收縮筋) ### 4.1 Purpose Temperature and shrinkage reinforcement controls cracking due to: - Concrete drying shrinkage (乾縮) - Seasonal temperature changes - Creep effects It is placed **perpendicular to the flexural reinforcement** in one-way slabs, and in **both directions** in slabs with equal reinforcement. > **Key concept**: Temperature/shrinkage steel is NOT structural — it does not increase load capacity. Its sole purpose is crack width control. ### 4.2 Minimum Temperature/Shrinkage Reinforcement Ratio $$\rho_{t\&s} = \frac{A_s}{b \cdot h}$$ (gross slab area) | Bar Type | Minimum ρt&s | |---|---| | Deformed bars and welded wire reinforcement | **0.0018** (0.18%) | | Prestressed slab steel used for shrinkage/temperature control | See Chapter 24.4.3 | Source: 7.6.4.1, 7.7.6.2.1. ### 4.3 Maximum Spacing for Temperature/Shrinkage Bars Maximum spacing: **min(5h, 450 mm)** --- ## Section 5: Development, Splice, and Opening Checks This audit pass did **not** verify any slab-specific high-low-slab rule, opening-reinforcement rule, or numeric splice-length rule directly from the PDF. Therefore, this skill intentionally does not preserve those items as technical requirements. When a project needs those checks, the AI should: - resolve the applicable slab clause from the PDF if one exists, - otherwise fall back to the general rebar development and splice clauses in Chapters 25.4 and 25.5, - and avoid inventing slab-step or opening details not explicitly supported by the source. --- ## Section 7: AI Design Check Table — Slab | Check | Condition | AI Action | |---|---|---| | Min thickness (one-way) | h < L/20 (simply supported) | ERROR: Slab may not control deflection — verify thickness | | Min thickness (two-way) | h below table 8.3.1.1 or 100/125mm minimum | ERROR: Two-way slab below minimum thickness | | Temp/shrinkage ratio | ρt&s < 0.0018 | ERROR: Insufficient temperature/shrinkage reinforcement | | Temp/shrinkage spacing | Bar spacing > min(5h, 450mm) | ERROR: Temperature/shrinkage bars too widely spaced | | Flexural spacing | Bar spacing > min(3h, 450mm) at critical section | ERROR: Flexural bar spacing exceeds limit | | Development / splice | Numeric ld or lap check required | WARNING: Resolve Chapter 25.4 and 25.5 from the PDF before checking. | | Cover — interior slab | C < 20mm for slabs not exposed | ERROR: Insufficient cover for interior slab | --- ## Section 8: MCP Tool Examples ```python # Search for slab minimum thickness taiwan-building-code_search_building_code(query="版 最小厚度 撓度 one-way two-way", limit=10) # Search for temperature/shrinkage reinforcement taiwan-building-code_search_building_code(query="溫度收縮鋼筋比 版 最小量", limit=10) # Search for slab opening requirements taiwan-building-code_search_building_code(query="版 開口 開孔 補強 鋼筋", limit=10) # Search for high-low slab (if referenced specifically in Taiwan code) taiwan-building-code_search_building_code(query="高低版 搭接 版高差 段差", limit=10) # Official interpretations taiwan-building-code_search_building_interpretations(query="版 高低差 搭接 斜筋補強") ``` --- ## Additional Resources - General requirements (cover, development length, lap splice fundamentals): [concrete-general-requirements](../../混凝土通用規定/concrete-general-requirements/) - Beam design (connected to slab as T-beam): [concrete-beam-design](../../混凝土梁設計/concrete-beam-design/)