Source: https://guthlabs.ai/docs/instruments/multi-span-continuous-beam-solver/qualification/

instrument qualification / verified-with-binding-errata

# Multi-Span Continuous Beam Solver qualification

Verified with errata that must be applied at binding time.

Status: **VERIFIED_WITH_ERRATA**Lifecycle: **verified-with-binding-errata**

## Ledger verdict

Verified with errata that must be applied at binding time.

**Status**: VERIFIED_WITH_ERRATA

**Tranche**: tranche-8

**Review vectors**: 4

**Ledger rows**: 1

## Applied errata

````
[
  {
    "vector": 2,
    "field": "span_1 reaction split / global A,B",
    "wrong": "left=14.875, right=5.125, A=14.875, B=18.375",
    "correct": "left=5.125, right=14.875, A=5.125, B=28.125 (C=6.75 unaffected)",
    "cause": "span1's left/right reaction split is transposed — confirmed by independent global-moment-about-A check: her triple gives 4*18.375+10*6.75=141, but 4R_B+10R_C must equal 2*20+7*20=180 for the stated loads; the corrected split (28.125,6.75) gives exactly 180. Her own derivation text computes the same 5.125 value and explicitly calls it 'the right-side reaction', then two lines later relabels it 'left' via a sign-flipped M_right/M_left substitution"
  }
]
````

### Stress-test correction

````
{
  "v1": {
    "vector_inputs": {
      "supports": "A-B-C",
      "span_lengths": [
        4,
        6
      ],
      "loads": [
        [
          {
            "type": "point",
            "magnitude": 10,
            "position_from_left": 1
          }
        ],
        [
          {
            "type": "point",
            "magnitude": 12,
            "position_from_left": 2
          }
        ]
      ],
      "EI": [
        1,
        4
      ]
    },
    "wrong_outputs": {
      "support_moments": {
        "A": 0,
        "B": -7.9090909091,
        "C": 0
      },
      "support_reactions": {
        "A": 0.5227272727,
        "B": 14.7954545455,
        "C": 6.6818181818
      }
    },
    "corrected_outputs": {
      "support_moments": {
        "A": 0,
        "B": -7.0454545455,
        "C": 0
      },
      "support_reactions": {
        "A": 11.1363636364,
        "B": 7.4671717172,
        "C": 3.3964646465
      }
    }
  },
  "v2": {
    "vector_inputs": {
      "supports": "A-B-C",
      "span_lengths": [
        3,
        5
      ],
      "loads": [
        [
          {
            "type": "udl",
            "intensity": 6
          }
        ],
        [
          {
            "type": "point",
            "magnitude": 20,
            "position_from_left": 1
          }
        ]
      ],
      "EI": [
        2,
        8
      ]
    },
    "wrong_outputs": {
      "support_moments": {
        "A": 0,
        "B": -9.1764705882,
        "C": 0
      },
      "support_reactions": {
        "A": 5.9411764706,
        "B": 17.8941176471,
        "C": 14.1647058824
      }
    },
    "corrected_outputs": {
      "support_moments": {
        "A": 0,
        "B": -9,
        "C": 0
      },
      "support_reactions": {
        "A": 12,
        "B": 24.04,
        "C": 1.96
      }
    }
  },
  "method": "independently verified two ways (per-span-EI three-moment theorem via triangular-BMD centroid decomposition; direct-stiffness-matrix FEM solve, 2 elements/3 nodes/fixed-end-moments) — both agree exactly. Reactions recomputed from the corrected moments via standard end-moment reaction correction, and checked against total-load equilibrium (ΣR = ΣP exactly in both vectors)."
}
````

## Adversarial re-test context

The full catalog was re-tested from boundary, convention, and self-check angles in 2,787 requests. Five genuine computational defects were independently verified and corrected. This page reports the current ledger state for this instrument; it does not imply product deployment or interface qualification.

## Release gate

Bind every attached correction, replay the affected vectors, enforce boundary validation, and preserve evidence before describing the executable surface as qualified.

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/multi-span-continuous-beam-solver/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/multi-span-continuous-beam-solver/mechanism/>)[03**Implementation**](<https://guthlabs.ai/docs/instruments/multi-span-continuous-beam-solver/implementation/>)

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json`

- `STRESS_TEST_RECEIPT.json`

- `tranche errata record`

- `STRESS_TEST_CORRECTIONS_APPLIED.json`