Code Clause Compass

Plain-English design-code clause reference

Code Clause Compass

Plain-English paraphrases of the clauses you cite most. 21 entries across 10 codes.

IS 456 Cl. 26.2.1

Development length of bars

Reinforcement must extend on either side of any section by a length sufficient to develop the bar's design strength through bond. The length depends on bar diameter, design stress, and the bond strength of the surrounding concrete (modified for bar surface and concrete grade).

Development length
Bond stress (M20)
Apply in Section Design
IS 456 Cl. 31.6.3

Two-way (punching) shear in flat slabs & footings

Punching shear is checked at a critical perimeter offset d/2 from the column face. Permissible shear stress is k_s × τ_c, where k_s depends on the column aspect ratio.

Critical perimeter shear
Permissible
Apply in Foundation Design
IS 456 Cl. 40.1

One-way (longitudinal) shear in beams

Nominal shear stress is computed at the support. Compared against permissible τ_c (varies with %p_t and grade) — concrete alone, then stirrups designed for the excess.

Nominal shear
Permissible
Apply in Section Design
IS 456 Cl. 26.5.3.1

Minimum reinforcement in beams

Tension reinforcement in any beam shall not be less than the value given by 0.85/fy × b × d for the rectangular tension zone — equivalent to ≈ 0.205% for Fe 415 and 0.17% for Fe 500.

Minimum %p_t
Apply in Section Design
IS 456 Cl. 26.5.3.2

Maximum reinforcement in compression

Maximum cross-sectional area of longitudinal reinforcement in a column = 6% of gross sectional area (4% if lapped). Beyond this, concrete placement is impractical.

Apply in Section Design
IS 456 Cl. 34 (Footings)

Footings — design checks

Footings must be designed for: bearing pressure under service loads, bending moments, one-way and two-way shear at appropriate critical sections, and development length of reinforcement past the critical bending section.

Apply in Foundation Design
IS 800 Cl. 8.2.2

Lateral-torsional buckling moment

Design bending moment of a laterally unsupported beam is taken as M_d = β_b × Z_p × f_bd, where f_bd is the design bending compressive stress accounting for buckling.

Design bending strength
Non-dimensional slenderness
IS 800 Cl. 9.3

Combined axial + bending (beam-column)

Member subject to combined axial force and bending must satisfy the interaction equation including second-order effects (P-δ amplifier on the bending term).

Interaction (combined)
IS 800 Cl. 3.7

Section classification (plastic / compact / semi-compact / slender)

Sections are classified by the b/t ratio of their plate elements. Plastic sections develop full plastic moment with rotation capacity; slender sections fail by local buckling before yield.

Outstand flange — plastic
Outstand flange — semi-compact
ε
IS 3370 Cl. 3.3 (Part 2)

Crack-width limits for water-retaining structures

Permissible crack width is 0.2 mm for severe exposure (e.g. liquid retaining face) and 0.1 mm where the surface is in direct contact with potable water.

Apply in Basement Design
IS 6403 Cl. 5

Safe bearing capacity of shallow foundations

Net ultimate bearing capacity is computed via the Terzaghi-style equation with shape, depth, and inclination factors. Safe bearing capacity is q_u / FoS (typical FoS = 2.5 to 3.0).

Net ult. bearing
Safe bearing
Apply in Geotechnical Analysis
IS 1893 Cl. 7.6 (Part 1)

Liquefaction — simplified screening

Sites with saturated cohesionless soils within 20 m of GL must be screened for liquefaction. Cyclic stress ratio (CSR) compared with cyclic resistance ratio (CRR) — FoS_liq < 1.0 indicates liquefiable.

CSR (NCEER)
Apply in Geotechnical Analysis
IS 10262 Cl. 4

Target mean strength for mix proportioning

Target mean strength = characteristic compressive strength + 1.65 × standard deviation. Standard deviation depends on grade (Table 1) for trial design; use site values once available.

Target mean
Apply in Concrete Mix Design
ACI 318 22.6.5

Two-way shear (punching) — ACI 318

Concrete punching shear strength v_c is the smaller of three expressions, accounting for column aspect ratio (β) and column type (interior/edge/corner — α_s factor).

v_c (smallest of 3)
Apply in Foundation Design
ACI 318 9.6

Minimum flexural reinforcement (beams)

Minimum reinforcement greater of 3√f'_c × b_w × d / f_y or 200 × b_w × d / f_y, in psi units. Prevents brittle failure at first cracking.

Apply in Section Design
AISC 360 F2.2

Lateral-torsional buckling (Cb factor)

Nominal flexural strength accounts for the moment gradient via C_b. Equation depends on whether the unbraced length L_b falls below L_p (plastic), between L_p and L_r (inelastic LTB), or above L_r (elastic LTB).

C_b
EC 2 §7.3.2

Crack-width control — Eurocode 2

Crack width w_k = s_r,max × (ε_sm − ε_cm). Limit values depend on exposure class and structure type (Table 7.1N).

Apply in Section Design
EC 3 §6.3.2

Lateral-torsional buckling — Eurocode 3

Design buckling resistance moment M_b,Rd = χ_LT × W_y × f_y / γ_M1, where χ_LT depends on slenderness λ̄_LT and an imperfection factor.

IS 456 Cl. 23.2

Deflection control by span-to-depth ratio

Rather than computing deflection, IS 456 lets you satisfy serviceability by keeping the span-to-effective-depth ratio below a basic value (20 simply supported, 26 continuous, 7 cantilever) times modification factors for tension and compression steel.

Basic span/depth
Allowable
Apply in Section Design
IS 456 Cl. 40

One-way shear — design shear strength of concrete

The shear a member carries without stirrups is τ_c·b·d, where τ_c is read from Table 19 as a function of the tension-steel ratio and concrete grade. If the nominal shear stress exceeds τ_c, shear reinforcement carries the balance — and the total is capped at τ_c,max.

Nominal shear stress
Concrete capacity
Apply in Section Design
ACI 318 §25.4.2

Development length of deformed bars in tension

ACI sets the tension development length from the bar stress, concrete strength and modification factors for bar location (ψ_t), coating (ψ_e), size (ψ_s) and lightweight concrete (λ), bounded by the confinement term (c_b + K_tr)/d_b ≤ 2.5. Good cover and transverse steel shorten the bar.

Development length
Apply in Section Design

Editorial paraphrases for educational reference — the official code text is always authoritative.