4. Design or engineering errors

4.1 Truss beams

• No triangulation

  Theoretical calculations can lead to the definition of a zero shear force in lattice girder panels (figure ). The elimination of triangulation in these panels creates a serious risk if a secondary parasitic force appears or if the loading is not perfectly symmetrical. On this subject, refer to article 5.202-1 of the CM 66 Rules, which defines a minimum shear force to be taken into account for floor or roof beams. $T_{\text{min}}⩾\frac{1}{4}{T}_{\text{max}}$

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