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What Rischio computes for retaining walls under AASHTO LRFD, 10th edition, article by article: each check and method, computed, in part or not.

Each check and method the code asks of a wall, in the code’s order, and whether Rischio computes it. The list comes from the engine itself, so it changes with every release.

AASHTO LRFD, 10th edition

ArticleWhat the code asksRischio
11.5.1, 11.5.3, 11.5.4.1

Retaining walls: service, strength and extreme event limit states

In part
3.4.1, Table 3.4.1-1Strength I
Table 3.4.1-1, 11.5.2, 11.5.7Service I, every factor 1.00, φ = 1.0
Table 3.4.1-1, C3.4.1, 11.5.6Extreme Event I: permanent loads 1.00, γEQ on live loads, EQ on the whole seismic earth pressure
Table 3.4.1-1Extreme Event II: vehicular collision CT
3.11.1

Earth pressure EH, ES and LS

In part
3.11.2

Compaction-induced pressure where equipment works within H/2

Not computed
3.11.3, 11.6.6

Undrained backfill: hydrostatic pressure plus earth pressure on submerged unit weights

Computed
3.11.5.1

p = k γs z, the resultant at H/3

Computed
3.11.5.2, Eq. 3.11.5.2-1

At rest k0 = 1 − sin φ′f (normally consolidated, vertical wall, level ground)

Not computed
Eq. 3.11.5.2-2

k0 = (1 − sin φ′f) OCR^sin φ′f

Not computed
3.11.5.3, Eq. 3.11.5.3-1

Coulomb ka

Computed
3.11.5.3

Trial wedge (Coulomb) for conditions outside Fig. 3.11.5.3-1, e.g. a broken backfill

Computed
3.11.5.4, Figs. 3.11.5.4-1 and -2

Passive kp for noncohesive soils (log spiral charts, reduction R for δ/φ)

Not computed
Eq. 3.11.5.4-1

Cohesive soils: pp = kp γs z + 2c√kp

Not computed
3.11.5.5

Equivalent-fluid method

Not computed
3.11.6

Surcharge loads ES and LS

Computed
3.11.6.1, Eq. 3.11.6.1-1

Uniform surcharge Δp = ks qs, ks = ka or ko

Computed
3.11.6.2, Eq. 3.11.6.2-1

Strip load on a wall restrained from movement

Not computed
Eq. 3.11.6.2-2

Point load

Not computed
Eq. 3.11.6.2-3

Infinitely long line load parallel to the wall: Δph = 4Q X² Z/(π R⁴)

Computed
Eq. 3.11.6.2-4

Finite line load perpendicular to the wall

Not computed
3.11.6.4.1, Tables 3.11.6.4.1-1 and -2

Live load surcharge Δp = k γs heq within H/2 of the wall, heq by height and distance to traffic

Computed
11.6

Conventional walls: gravity and semigravity (cantilever)

In part
11.6.1.2

Loading: earth and water, surcharges, self-weight; the fill over the heel is part of the wall

Computed
11.6.2.2, 11.5.2Service: vertical and lateral movement
10.6.2.4, 10.6.2.5

Settlement of the wall's footing at Service I

Computed
11.6.3.1, 11.5.3Strength: bearing, overturning (eccentricity), sliding, deep-seated failure
11.6.3.2

Bearing resistance

Computed
Eq. 11.6.3.2-1

On soil: σv = ΣV/(B − 2e), uniform

Computed
10.6.3.1.1, 10.6.3.1.2a, Eq. 10.6.3.1.2a-1

Nominal bearing resistance on B′ by the footing's equation

Computed
10.6.3.2

Bearing resistance of rock

Not computed
11.6.3.3

Eccentricity: resultant in the middle two-thirds on soil; replaces overturning

Computed
11.6.3.4

Subsurface erosion: scour, hydraulic gradient ≤ 0.20 (silts, clays) or 0.30, uplift and seepage

Not computed
11.6.3.6 → 10.6.3.4

Sliding: φτ Rτ + φep Rep

Computed
Eq. 10.6.3.4-2

Cohesionless: Rτ = C V tan φf, C = 1.0 cast against soil, 0.8 precast

Computed
10.6.3.4, Fig. 10.6.3.4-1

Clay: the lesser of Su and half the normal stress

Computed
Eq. 10.6.3.4-1

Passive component φep Rep

Not computed
11.6.3.7, 11.6.3.1 → 10.6.3.5

Overall stability by limit equilibrium, Strength I, φ 0.75 / 0.65

Not computed
11.5.4, 11.6.5Extreme Event I, conventional walls
11.6.5.2.1

kh0 = As (1.2 As on Site Class A, B or B/C), kv = 0

Computed
11.6.5.2.2, A11.5

kh for wave scattering and displacement: 0.5 kh0 for 1 to 2 in., or a Newmark-based method

In part
A11.5.1

Kavazanjian et al. (1997)

Not computed
A11.5.2

NCHRP 611, Anderson et al. (2008): wave scattering α and displacement

Not computed
A11.5.3

Bray et al. (2010)

Not computed
11.6.5.3

Seismic active force PAE: M–O or GLE

Computed
A11.3.2, Eq. A11.3.2-1

c–φ backfill: Anderson et al.'s wedge

Not computed
A11.3.3

GLE (or a Coulomb trial wedge) where M–O doesn't apply

Computed
11.6.5.4

Nonyielding walls: kh = 1.0 kh0

Not computed
11.6.5.1, Eq. 11.6.5.1-1

Wall inertia PIR = kh(Ww + Ws); 100% PAE + 50% PIR, and 50% PAE (≥ static) + 100% PIR

Computed
11.6.5.1, 11.5.8, 10.6.4

Bearing (φ 0.8), sliding (φ 1.0) and overall stability (φ 0.9) at Extreme Event I

Computed
11.6.5.1, 10.6.4.2

Eccentricity: middle 2/3 at γEQ = 0 to middle 8/10 at γEQ = 1, interpolated

Computed
11.6.5.5, A11.4

Seismic passive by log spiral, δ = 2/3 φ; static methods for embedment < 5 ft

Not computed
11.11, C11.11.1

Prefabricated modular walls: gabions

Not computed
3.11.5.9, Table C3.11.5.9-1

Coulomb on the plane from the top module's back corner to the bottom heel; φf 34° or 30° by default; δ by the table

Computed
11.11.3, C11.11.3Settlement; longitudinal differential slope under 1/200
11.11.4.1

Rigid body; stability at every module level

Not computed
11.11.4.2 → 10.6.3.4

Sliding: the lesser φf of fill and foundation, 30° without data

Not computed
11.11.4.3 → 10.6.3

Bearing: point supports, at least 80% of the fill weight transferred

Not computed
11.11.4.4 → 11.6.3.3

Eccentricity per 11.6.3.3; at most 80% of the fill resists overturning

Not computed
11.11.4.5

Scour-sensitive areas, subsurface erosion

Not computed
11.11.4.6 → 11.6.3.7

Overall stability

Not computed
11.11.6 → 11.6.5Seismic, each lift
11.10

Mechanically stabilized earth walls

In part
11.10.2.1, C11.10.2.1

Reinforcement length at least 0.7H (8 ft in the commentary), uniform

Computed
11.10.2.2, Table C11.10.2.2-1

Minimum front embedment: frost; 2.0 ft sloping or erodible, 1.0 ft level; H/20 to H/5

Computed
11.10.4Service limit state
11.10.4.1 → 11.6.2, Table C11.10.4.1-1

Settlement; differential distortion by facing (1/100 to 1/600; 1/500 full-height panels)

Computed
11.10.4.2

Lateral displacement

Computed
11.10.4.3, Eq. 11.10.4.3-1

Soil failure: reinforcement strain ≤ 2% (stiff face) or 2.5% (flexible), Stiffness Method

Computed
11.10.5

External stability, the reinforced mass a rigid body

In part
11.10.5.1, 11.10.5.2, 3.11.5.8.1

Retained thrust Pa = 0.5 ka γ h² at h/3, Coulomb ka with δ ≤ 0.67 of the lesser φ′

Computed
11.10.5.3 → 10.6.3.4

Sliding at the base

Computed
11.10.5.3

Friction: lesser of φr and φf (strips); also ρ = 2/3 φ (sheets, grids); 30° and 34° without data

Computed
11.10.5.3

Sliding at the lowest reinforcement layer

Computed
11.10.5.5 → 11.6.3.3

Eccentricity: middle two-thirds on soil (L/3), nine-tenths on rock

Computed
11.10.5.4 → 10.6.3.1, 10.6.3.2

Bearing: uniform pressure on L − 2e (L if e < 0)

In part
10.6.3.1.2a, C11.10.5.4

qn by Eq. 10.6.3.1.2a-1 on L′, no inclination factors

Computed
11.10.5.6 → 11.6.3.7

Overall and compound stability (LEA in three steps)

Not computed
11.10.6

Internal stability: rupture, pullout, connection

Computed
11.10.6.2.1

Tmax: Coherent Gravity for steel, Stiffness for geosynthetics, Simplified (B11) acceptable for both

Computed
11.10.6.2.1d

Coherent Gravity Method: kr from k0 to ka over 20 ft, Meyerhof σv

Computed
11.10.6.2.1e

Stiffness Method: Dtmax, Φg, Φfs

Computed
B11.2, Eq. B11.2-1

Simplified Method: Tmax = Sv kr (γr Z + γf S)

Computed
Fig. B11.2-1

kr/ka: strips 1.7 to 1.2, grids and bar mats 2.5 to 1.2, geosynthetics 1.0; strip multiplier for all steel pullout

Computed
11.10.6.2.1c

ka with δ = β = 0: tan²(45 − φ/2); battered face by Eq. C11.10.6.2.1c-2

Computed
11.10.6.2.1b

Tributary thickness Sv; Sv over 2.7 ft not without full-scale data

Computed
11.10.6.3.1, Fig. 11.10.6.3.1-1

Active zone: bilinear (inextensible), Rankine (extensible, batter < 10°), Coulomb otherwise

Computed
11.10.6.3.2, Eq. 11.10.6.3.2-1

Pullout: Le ≥ γp-EV Tmax/(φ F* α σv C Rc)

Computed
Fig. 11.10.6.3.2-2, Table 11.10.6.3.2-1

Default F* and α: strips 1.2 + log Cu ≤ 2.0 to tan φ at 20 ft (Cu 4 if unknown); grids 20 t/St to 10 t/St; geosynthetics 0.67 tan φ; α 1.0 / 0.8 / 0.6

Computed
11.10.6.4.1, Eq. 11.10.6.4.1-1

Rupture: γp-EV Tmax ≤ φ Tal Rc

Computed
11.10.6.4.3a

Steel: Tal = Ac Fy / b

Computed
11.10.6.4.2a

Sacrificial thickness: zinc 0.58 then 0.16 mil/yr, steel 0.47 mil/yr per side; nonaggressive backfill

Computed
11.10.6.4.3b

Geosynthetics: Tal = Tult/(RFID RFCR RFD), RFID ≥ 1.05, RFD ≥ 1.1

Computed
11.10.6.2.2, 11.10.6.4.4, Eq. 11.10.6.4.1-2, B11.2-3

Connection: To = Tmax, γp-EV To ≤ φ Tac Rc (geosynthetics Tac = Tult CRcr / RFD)

Computed
11.10.10.1, 3.11.6.3

Concentrated dead loads: 2V:1H spread, superposition (Ttotalf)

Not computed
11.10.10.2

Traffic barrier impact on the top layers (CT)

Computed
11.10.11

MSE abutments: a footing on the reinforced zone

In part
11.10.7Extreme Event I, MSE walls
11.10.7.1 → 11.6.5

External: PAE plus PIR on a mass 0.5H wide (H2 for slopes)

Computed
11.10.7.2

Internal: Pi = kh Wa distributed (by Lei for steel, uniform for geosynthetics), Ttotalf = γseis (Tmax + Tmd)

Computed
Eq. 11.10.7.2-7

Seismic pullout with 0.8F*

Computed
11.10.7.3

Facing connections under earthquake (0.8 if frictional)

Computed
11.8

Nongravity cantilevered walls

Not computed
11.9

Anchored walls

Not computed
11.12

Soil nail walls

Not computed

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