4.4　Guyed Steel Mast

4.4.1　The internal force of guyed steel mast body may be analyzed based on continuous compressive bending member as the elastic support at guy node.The eccentric bending moment at guy node is also taken into account.Beam cable element or rod cable elements can be used for finite element method calculation when necessary.

The bending stiffness variation after shear deformation shall be considered for latticed tower body，and the stiffness shall multiply by reduction coefficient ξ.The reduction coefficient may be determined according to the following formula：

Where，l0——calculated length（m）of member between elastic supports；

i——radius of gyration（m）of member section；

λ0——conversion slenderness ratio of member between elastic supports，which is calculated based on the provisions set out in Article 5.2.4.

4.4.2　The guy of guyed steel mast can be calculated as parabola one end connecting to the of tower body，and the concentrated load acting on the guy may be converted into uniform load.

The section strength of guy shall be calculated according to the following formula：

Where，N——design value of guy tension（N）；

A——sectional area of guy（mm2）；

f——design value of tensile strength of guy（N/mm2）.

4.4.3　The initial force of guy shall be determined based on member deformation，internal force，stability，bearing capacity of guy and other factors，and 100N/mm2-250N/mm2 is preferred.

4.4.4　The overall stability checking calculation shall be conducted for guyed steel mast，and the overall stability safety coefficient calculated based on bending critical stress of member shall not be less than 2.0.

4.4.5　Guy arrangement of guyed steel mast：There are three symmetric directions in 120°or four symmetric directions in 90°on the plane，and the angle between guy and horizontal plane is 40°-60°.

4.4.6　The height of guyed steel mast should not be more than 40m.