{
  "description": "2×20 m教学梁共同基准；不含真实截面抗力设计",
  "units": {
    "length": "m",
    "force": "kN",
    "moment": "kN m",
    "EI": "kN m^2",
    "displacement": "m"
  },
  "signs": {
    "v": "down positive",
    "theta": "clockwise positive",
    "reactions_in_tables": "upward magnitude",
    "section_moment": "sagging positive"
  },
  "E": 30000000.0,
  "I": 4,
  "EI": 120000000.0,
  "g1": 30,
  "g2": 10,
  "nodes": [
    {
      "id": 1,
      "x": 0,
      "v_fixed": true
    },
    {
      "id": 2,
      "x": 10,
      "v_fixed": false
    },
    {
      "id": 3,
      "x": 20,
      "v_fixed": true
    },
    {
      "id": 4,
      "x": 30,
      "v_fixed": false
    },
    {
      "id": 5,
      "x": 40,
      "v_fixed": true
    }
  ],
  "elements": [
    {
      "id": 1,
      "i": 1,
      "j": 2,
      "EI": 120000000.0
    },
    {
      "id": 2,
      "i": 2,
      "j": 3,
      "EI": 120000000.0
    },
    {
      "id": 3,
      "i": 3,
      "j": 4,
      "EI": 120000000.0
    },
    {
      "id": 4,
      "i": 4,
      "j": 5,
      "EI": 120000000.0
    }
  ],
  "stage_note": "一期两跨简支的中支点左右转角独立；连续连接以一期已发生状态为参考，只对二期转角增量施加连续条件。不得将一期两个端转角强行合并。",
  "once": {
    "upward_reactions_kN": [
      300,
      1000,
      300
    ],
    "middle_support_moment_kNm": -2000,
    "span_midpoint_moment_kNm": 1000,
    "span_midpoint_v_mm": 0.2777777777777779,
    "nodal_dofs": [
      0.0,
      5.5555555555555565e-05,
      0.0002777777777777779,
      -1.3888888888888886e-05,
      0.0,
      -1.8947806286936006e-20,
      0.0002777777777777776,
      1.3888888888888888e-05,
      0.0,
      -5.555555555555554e-05
    ]
  },
  "staged": {
    "upward_reactions_kN": [
      375,
      850,
      375
    ],
    "middle_support_moment_kNm": -500,
    "span_midpoint_moment_kNm": 1750,
    "span_midpoint_v_mm": 0.590277777777778
  },
  "stage1_single_span": {
    "nodal_dofs": [
      0.0,
      8.333333333333336e-05,
      0.0005208333333333335,
      4.11430560402719e-21,
      0.0,
      -8.333333333333337e-05
    ],
    "end_forces": [
      [
        -300.0000000000001,
        0.0,
        1.1368683772161603e-13,
        -1500.0000000000005
      ],
      [
        1.1368683772161603e-13,
        1500.0000000000007,
        -300.0000000000001,
        -4.547473508864641e-13
      ]
    ]
  },
  "stage2_increment": {
    "nodal_dofs": [
      0.0,
      1.3888888888888891e-05,
      6.944444444444447e-05,
      -3.4722222222222215e-06,
      0.0,
      -4.7369515717340015e-21,
      6.94444444444444e-05,
      3.472222222222222e-06,
      0.0,
      -1.3888888888888884e-05
    ],
    "end_forces": [
      [
        -75.00000000000003,
        -1.4210854715202004e-14,
        -24.99999999999997,
        -250.0000000000001
      ],
      [
        25.000000000000014,
        250.0000000000001,
        -125.00000000000001,
        499.99999999999994
      ],
      [
        -124.99999999999999,
        -499.99999999999994,
        24.999999999999986,
        -249.99999999999983
      ],
      [
        -25.00000000000003,
        249.99999999999983,
        -74.99999999999997,
        1.4210854715202004e-14
      ]
    ]
  },
  "scope": "线性等截面Euler—Bernoulli梁竖弯，支点无沉降；忽略闭合强迫变形、收缩徐变、预应力。"
}