Uplift plates & anchors

The uplift tool contains two separate analyses: explicit plate breakout by the declared Meyerhof–Adams/Das formulation, and straight-shaft grouted ground-anchor design and test-record screening under FHWA GEC 4. They do not share a generic “uplift factor,” and neither path silently supplies units, groundwater, bond strength, or design factors.

Status and scope

Validated against the published sources

The formulas, strict applicability checks, SI/US twins, and the public GEC 4 worked example are implemented and validated by automated tests. See Validation & provenance for the evidence.

Plate: horizontal circular or rectangular plates in one coherent drained or undrained failure mechanism.
Ground anchor: one straight-shaft grouted anchor with traceable ground-grout and tendon-grout capacities.
Not included: helical anchors, belled shafts, anchor groups, mixed drained/undrained failure mechanisms, or arbitrary strip anchors.

Use the dedicated helical-pile method for helices and thedrilled-shaft method for shaft or bell uplift.

Plate breakout

Plan geometry is explicit. A circle uses its diameter; a rectangle uses width and length. The engine derives area A, perimeter P, aspect ratio, and characteristic widthB* = 4A/P. This exactly recovers the diameter of a circle and the side of a square.

B_q = 1 + ½(P/A)H_m K_u tan(φ_min)(1 + mH_m/B*), Q_n = W_p + Aσ′_v B_q

Cohesionless plate

Q_n = W_p + Aσ′_v + A c_u,min B_c(H/H_cr), B_c ≤ 9

Cohesive plate

H_m = min(H,H_cr). In deep mode, the frictional or cohesive breakout term freezes at the critical depth while effective overburden remains evaluated at the actual plate depth. The response reports nominal resistance, ASD or LRFD design resistance, shallow/deep mode, critical depth, component forces, and the declared failure-surface geometry.

The rectangular 4A/P adaptation is explicit and auditable. Aspect ratios above 10 are rejected instead of being treated as a plate.

Layers and groundwater

Layers must begin at zero, remain ordered and contiguous, and cover the complete embedment. The conservative layered envelope integrates effective overburden through every layer and uses the minimum declared friction angle or undrained strength over the failure depth.

Dry: the declared total unit weights are used.
Hydrostatic: water-table depth and water unit weight are both required; submerged unit weight must remain positive.
Strength: cohesionless layers require 20° ≤ φ ≤ 45°; cohesive layers require explicit positive undrained strength.

Mixing drained and undrained layers is rejected because the current model has no validated composite failure mechanism.

FHWA GEC 4 anchors

The anchor path follows the preliminary load-transfer and structural screens in FHWA-IF-99-015, Ground Anchors and Anchored Systems. Ultimate transfer is supplied per unit bond length from a named GEC 4 table, qualified project test, or other explicit source. The engine does not infer it from grout strength.

Q_g,u = η_b Σ(q_u,i ΔL_i)

Layered ground-grout bond

R_d = min(R_ground-grout, 0.60 T_SMTS, R_tendon-grout)

Governing design resistance

Soil and intermediate-geomaterial bonds are limited to 4.5–12 m; competent rock to 3–10 m.
Bar unbonded length is at least 3 m; strand unbonded length is at least 4.5 m.
Inclination is 10–45 degrees below horizontal.
Bond-zone center cover is at least 4.5 m; shallower ground-mass breakout is unsupported.
Preliminary ASD factors are at least 2 for soil/intermediate geomaterial and 3 for competent rock. LRFD requires a project factor and reference.

Ground-grout bond, tendon rupture, and tendon-grout bond are shown separately. Grout compressive strength is retained only for material traceability. Tendon-grout resistance requires qualified product or test evidence such as ASTM A981 data.

Production testing

GEC 4 requires every production anchor to be load tested. The tool records proof, performance, or extended-creep observations; checks the applicable 1.20, 1.33, or 1.50 maximum test-load multiplier; evaluates apparent free length; and applies the published creep screens.

T_d ≤ 0.60T_SMTS, T_lockoff ≤ 0.70T_SMTS, T_test ≤ 0.80T_SMTS; L_a = Δ_e EA/(T_test − T_align)

Tendon limits and apparent free length

Proof/performance short hold: movement from 1 to 10 minutes must not exceed 1 mm.
If the hold is extended: movement from 6 to 60 minutes must not exceed 2 mm.
Apparent free length must be at least jack length plus 80% of the design unbonded length.
An untested anchor remains visibly design-only-not-tested and is not accepted for service.

Test record is not the field procedure

The software screens the submitted test observations; it does not operate the jack, establish an independent movement reference, verify calibration certificates, or replace the engineer’s field acceptance decision and complete performance/extended-creep plots.

Fail-closed limits

The request is rejected, rather than extrapolated, for:

missing unit system, groundwater data, design basis, method ID, or evidence reference;
gapped, overlapping, reversed, or too-short plate and bond profiles;
mixed plate failure mechanisms or mixed soil/rock anchor bond zones;
unsupported aspect ratio, friction angle, anchor inclination, cover, or bond length;
inconsistent SI/US water unit weight or nonpositive submerged unit weight;
test records whose loads, movements, or observation chronology are impossible.

Validation evidence

Deterministic gates

Component and ASD/LRFD algebraic identities.
SI/US physical twins for plate and anchor results.
Hydrostatic integration, layer-envelope, aspect-ratio, and orientation invariants.
FHWA GEC 4 worked example: 100 kN/m over 8.9 m gives 890 kN nominal and 445 kN at FS 2.
60/70/80% tendon limits, creep screens, apparent free length, and negative applicability tests.
Identical strict request/result semantics through core, contracts, Convex, REST/Excel serialization, saved rerun, and reports.