(a) Cast-in-place

(b) Precast in-plant

(c) Precast on-site including tilt-up

**Table 11.3.1.1—Minimum wall thickness h**

Wall type | Minimum thickness h |
||
---|---|---|---|

Bearing^{[1]} |
Greater of: | 4 in. | (a) |

^{1}/_{25} the lesser of unsupported length and unsupported height |
(b) | ||

Nonbearing | Greater of: | 4 in. | (c) |

^{1}/_{30} the lesser of unsupported length and unsupported height |
(d) | ||

Exterior basement and foundation^{[1]} |
7.5 in. | (e) |

^{[1]}Only applies to walls designed in accordance with the simplified design method of 11.5.3.

**that can accompany the factored axial force for each applicable load combination. The factored axial force**

*M*_{u}**at given eccentricity shall not exceed**

*P*_{u}**ϕ**, where

*P*_{n,max}**shall be as given in 22.4.2.1 and strength reduction factor**

*P*_{n,max}**ϕ**shall be that for compression-controlled sections in 21.2.2. The maximum factored moment

**shall be magnified for slenderness effects in accordance with 6.6.4, 6.7, or 6.8.**

*M*_{u}**ϕ**, including (a) through (c). Interaction between axial load and moment shall be considered.

*S*≥_{n}*U*(a) **ϕ P_{n} ≥ P_{u}**

(b) **ϕ M_{n} ≥ M_{u}**

(c) **ϕ V_{n} ≥ V_{u}**

**shall be permitted to be calculated by:**

*P*_{n}(11.5.3.1) |

**for use with Eq. (11.5.3.1) shall be in accordance with Table 11.5.3.2.**

*k***Table 11.5.3.2—Effective length factor k for walls**

Boundary conditions | k |
---|---|

Walls braced top and bottom against lateral translation and: | |

(a) Restrained against rotation at one or both ends (top, bottom, or both) | 0.8 |

(b) Unrestrained against rotation at both ends | 1.0 |

Walls not braced against lateral translation | 2.0 |

*V*shall be calculated in accordance with 11.5.4.2 through 11.5.4.8. Alternatively, for walls with

_{n}**, it shall be permitted to design for in-plane shear in accordance with the strut-and-tie method of Chapter 23. In all cases, reinforcement shall satisfy the limits of 11.6, 11.7.2, and 11.7.3.**

*h*≤ 2_{w}*ℓ*_{w}**is thickness of wall and**

*h***shall be taken equal to**

*d***0.8**. A larger value of

*ℓ*_{w}**, equal to the distance from extreme compression fiber to center of force of all reinforcement in tension, shall be permitted if the center of tension is calculated by a strain compatibility analysis.**

*d**V*at any horizontal section shall not exceed .

_{n}*V*shall be calculated by:

_{n}V = _{n}V+ _{c}V_{s} | (11.5.4.4) |

**in accordance with Table 11.5.4.6, where**

*V*_{c}**is positive for compression and negative for tension, and the quantity**

*N*_{u}**is expressed in psi.**

*N*/_{u}*A*_{g}**Table 11.5.4.6— V_{c}: nonprestressed and prestressed walls**

Calculation option | Axial force | V_{c} |
||
---|---|---|---|---|

Simplified | Compression | (a) | ||

Tension | Greater of: | (b) | ||

0 | (c) | |||

Detailed | Tension or compression | Lesser of: | (d) | |

Equation shall not apply if ( M/_{u}V— _{u}ℓ/2) is negative._{w} |
(e) |

**or one-half the wall height, whichever is less, shall be permitted to be designed for**

*ℓ*/2_{w}**calculated using the detailed calculation options in Table 11.5.4.6 at a distance above the base of**

*V*_{c}**or one-half the wall height, whichever is less.**

*ℓ*/2_{w}*V*shall be calculated in accordance with 22.5.

_{n}**, minimum**

*V*≤ 0.5ϕ_{u}*V*_{c}**ρ**and minimum

_{ℓ}**ρ**shall be in accordance with Table 11.6.1. These limits need not be satisfied if adequate strength and stability can be demonstrated by structural analysis.

_{t}**Table 11.6.1—Minimum reinforcement for walls with in-plane V_{u}** ≤

**0.5**

_{ϕ}*V*_{c}Wall type | Type of nonprestressed reinforcement | Bar/wire size | f, psi_{y} |
Minimum longitudinal^{[1]}, ρ_{ℓ} |
Minimum transverse, ρ_{t} |
---|---|---|---|---|---|

Cast-in-place | Deformed bars | ≤ No. 5 | ≥ 60,000 | 0.0012 | 0.0020 |

< 60,000 | 0.0015 | 0.0025 | |||

> No. 5 |
Any | 0.0015 | 0.0025 | ||

Welded-wire reinforcement | ≤ W31 or D31 | Any | 0.0012 | 0.0020 | |

Precast^{[2]} |
Deformed bars or welded-wire reinforcement | Any | Any | 0.0010 | 0.0010 |

^{[1]}Prestressed walls with an average effective compressive stress of at least 225 psi need not meet the requirement for minimum longitudinal reinforcement ρ_{ℓ}.

^{[2]}In one-way precast, prestressed walls not wider than 12 ft and not mechanically connected to cause restraint in the transverse tion, the minimum reinforcement requirement in the direction normal to the flexural reinforcement need not be satisfied.

**, (a) and (b) shall be satisfied:**

*V*≥ 0.5ϕ_{u}*V*_{c}(a) **ρ _{ℓ}** shall be at least the greater of the value calculated by Eq. (11.6.2) and 0.0025, but need not exceed

**ρ**required by 11.5.4.8.

_{t}ρ _{ℓ} ≥ 0.0025 + 0.5(2.5 — h_{w}/ℓ)(ρ_{w}_{t} — 0.0025) |
(11.6.2) |

(b) **ρ _{t}** shall be at least 0.0025

**of longitudinal bars in cast-in-place walls shall not exceed the lesser of**

*s***3**and 18 in. If shear reinforcement is required for in-plane strength, spacing of longitudinal reinforcement shall not exceed

*h***.**

*ℓ*/3_{w}**of longitudinal bars in precast walls shall not exceed the lesser of (a) and (b):**

*s*(a) **5 h**

(b) 18 in. for exterior walls or 30 in. for interior walls

If shear reinforcement is required for in-plane strength, ** s** shall not exceed the smallest of

**3**, 18 in., and

*h***.**

*ℓ*/3_{w}**greater than 10 in., except basement walls and cantilever retaining walls, distributed reinforcement for each direction shall be placed in two layers parallel with wall faces in accordance with (a) and (b):**

*h*(a) One layer consisting of at least one-half and not exceeding two-thirds of total reinforcement required for each direction shall be placed at least 2 in., but not exceeding ** h/3**, from the exterior surface.

(b) The other layer consisting of the balance of required reinforcement in that direction, shall be placed at least ^{3}/_{4} in., but not greater than ** h/3,** from the interior surface.

**of transverse reinforcement in cast-in-place walls shall not exceed the lesser of**

*s***3**and 18 in. If shear reinforcement is required for in-plane strength,

*h***shall not exceed**

*s***.**

*ℓ*/5_{w}**of transverse bars in precast walls shall not exceed the lesser of (a) and (b):**

*s*(a) **5 h**

(b) 18 in. for exterior walls or 30 in. for interior walls

If shear reinforcement is required for in-plane strength, ** s** shall not exceed the least of

**3**, 18 in., and

*h*

*ℓ*/5_{w}**exceeds**

*A*_{st}**0.01**, longitudinal reinforcement shall be laterally supported by transverse ties.

*A*_{g}**in tension at the corners of the openings.**

*f*_{y}(a) Cross section is constant over the height of the wall

(b) Wall is tension-controlled for out-of-plane moment effect

(c) **ϕ M_{n}** is at least

**, where**

*M*_{cr}**is calculated using**

*M*_{cr}**as provided in 19.2.3**

*f*_{r}(d) ** P_{u}** at the midheight section does not exceed

**0.06**

*f'*_{c}*A*_{g}(e) Calculated out-of-plane deflection due to service loads, **Δ _{s}**, including

**effects, does not exceed**

*P*Δ

*ℓ*/150_{c}(a) The spacing of the concentrated loads

(b) The edges of the wall panel

*M*at midheight of wall due to combined flexure and axial loads shall include the effects of wall deflection in accordance with (a) or (b):

_{u}(a) By iterative calculation using

M = _{u}M+ _{ua}PΔ_{u}_{u} | (11.8.3.1a) |

where ** M_{ua}** is the maximum factored moment at midheight of wall due to lateral and eccentric vertical loads, not including

**effects.**

*P*Δ**Δ _{u}** shall be calculated by:

(11.8.3.1b) |

where ** I_{cr}** shall be calculated by:

(11.8.3.1c) |

and the value of ** E_{s}/E_{c}** shall be at least 6.

(b) By direct calculation using:

(11.8.3.1d) |

**Δ**, shall be calculated in accordance with Table 11.8.4.1, where

_{s}**is calculated by 11.8.4.2.**

*M*_{a}**Table 11.8.4.1—Calculation of** Δ_{s}

M_{a} | Δ_{s} | |
---|---|---|

≤ (2/3)M_{cr} | (a) | |

> (2/3)M_{cr} | (b) |

_{cr}and

**Δ**shall be calculated by (a) and (b):

_{n}(a) | (11.8.4.3a) |

(b) | (11.8.4.3b) |

*I*shall be calculated by Eq. (11.8.3.1c).

_{cr}