Concrete General Requirements

Concrete General Requirements

Overview

Foundational knowledge for reinforced concrete design in Taiwan, limited to content directly verified against the uploaded 112-code PDF. This skill focuses on reinforcement nomenclature, concrete cover, and where to look in the code for development length and splice requirements. This skill is the prerequisite for all component-specific concrete skills (beam, column, slab, wall).

Section 1: Code Navigation

1.1 Where to Verify Shared Rules

This skill intentionally does not restate unverified material-strength tables or development-length formulas unless they have been transcribed clause-by-clause from the PDF.

Section 2: Reinforcement Cover (C)

2.1 What is Concrete Cover?

Concrete cover (C) is the minimum distance from the concrete surface to the outermost reinforcing steel, as described in Chapter 20.5.1.1. When transverse reinforcement surrounds the main bars, the cover is measured to the outside face of the stirrup, tie, or spiral.

Source: 20.5.1.1, 20.5.1.3.1.

2.2 Minimum Cover by Exposure Condition

<!-- PDF aligned to Chapter 20.5.1.3.1 -->

Design Check Triggers:

• Cover < minimum → ERROR: Insufficient cover. Cite applicable table.
• Cover specified to main bar face (not stirrup face) → WARNING: Clarify measurement convention.

2.3 Fire Resistance Cover

Fire-resistance cover may be controlled by 建築技術規則 rather than Chapter 20.5.1 alone. Check both requirements when fire rating is part of the design brief.

Source: 20.5.1.1.

Section 3: Reinforcement Nomenclature

3.1 Main Bars (主筋)

• Primary load-carrying reinforcement used to resist flexure, axial force, or both depending on member type
• Typically placed near the tension or compression faces that govern the design section

3.2 Stirrups (箍筋) — Beams

• Transverse reinforcement used in beams
• Detailed requirements are governed by beam clauses and Chapter 25.7

3.3 Ties (繫筋) — Columns

• Transverse reinforcement used in columns
• Detailed spacing and support requirements are governed by Chapter 10.7 and Chapter 25.7

3.4 Relationship between C, Ties/Stirrups, and Main Bars

Concrete surface
│← C (cover to stirrup/tie face) →│
                                   ├── Stirrup/Tie (D10)
                                   │← D_stirrup →│← D_main/2 →│
                                                               ← Main bar centroid

The drawing and section calculations must distinguish between:

• cover to the outermost transverse steel, and
• bar-centroid locations used in effective-depth calculations.

Design Check: Do not trade off cover against effective depth. Cover below Chapter 20.5.1 is a direct code violation.

Section 4: Development Length (錨定長度)

Development length is governed by Chapter 25.4. Because the exact formulas, factors, and exceptions were not fully transcribed from the PDF in this pass, this skill deliberately avoids restating numerical development-length equations here.

Verified shared rules from Chapter 25.4:

• bars must be developed on both sides of the design section by embedment length, hooks, headed bars, mechanical devices, or combinations: 25.4.1.1
• hooks and heads do not count toward compression-bar development: 25.4.1.2
• development length is computed without using strength-reduction factor $\phi$: 25.4.1.3
• the $\sqrt{f'_c}$ term used for development-length calculations is capped by 700 kgf/cm² [70 MPa] concrete strength, expressed in 25.4.1.4 as a calculation limit on $\sqrt{f'_c}$: 25.4.1.4
• for bars with $f_y \ge 550$ MPa and center spacing less than 15 cm, transverse reinforcement must provide $K_{tr} \ge 0.5d_b$: 25.4.2.2

Use this rule for source control:

• if a design check depends on a numeric ld value, the AI must first resolve it from Chapter 25.4 or from a verified table transcribed from that chapter.