Rotational Restraint CD,B

Determination of the rotational stiffness C_D,B due to the cross-section deformation

c_{D, B} = C_{D, B} / e

C_{D, B} = \sqrt{E \cdot t_{w}^{3} \cdot G \cdot I_{T, G} / (h - t_{f})}

I_{T, S} = (h - t_{f}) \cdot t_{w}^{3} / 3

I_{T, G} = (I_{T} - I_{T, S}) / 2

E	Modulus of elasticity
t_w	Web thickness of the truss or the supported component
G	G-modulus
h	Height of the truss or the supported component
t_f	Flange thickness of the truss
b	Truss width
e	Distance of the purlins

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