44. Recording inter-nodal loading

Direct Stiffness Method - Beam and Frame Analysis
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Hi Dr Sean

  • I am wondering why we use simple formula ‘wl^2/12’ to calculate ‘Moment’ for inter-nodal loading. We solved stiffness matrix equations to calculate ‘Moment’ at primary nodes.
  • Locking the memeber with fixed-ends for inter-nodal loading is kind of standard procedure?

Thanks
Yan

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We use this formula because we’re calculating the fixed-end moment that the inter-nodal loading will apply at each end of the loaded element. The stiffness method can only accommodate loading at a nodal point - so this is required when we have loading between nodes that we want to consider - otherwise the influence of this loading would not be captured.