TR.23.1 Member Truss Specification

This command may be used to model a specified set of members as TRUSS members.

This specification may be used to specify truss type members in a PLANE, SPACE, or FLOOR structure. The truss members are capable of carrying only axial forces. For example, bracing members in 2D (i.e., PLANE or FLOOR) or 3D (i.e., SPACE) frames will often be truss type members.

Tip: This command is unnecessary when a truss type structure has already been specified using the command STAAD TRUSS.

General Format

MEMBER TRUSS

member-list (TENSION f1)

Where:

Parameter	Definition
TENSION `f1`	optional initial tension in the truss member, in current units Note: The `TENSION` parameter is ignored except in Nonlinear Cable Analysis. For that analysis type, a truss with pretension is considered to be nonlinear (large displacement). Also for that analysis type, trusses without preload are assumed to be linear members that carry both tension and compression regardless of this command.

Example

MEMB TRUSS
1  TO  8  10  12  14  15

Notes

The TRUSS member has only one degree of freedom-the axial deformation.
Member Releases are not allowed for TRUSS members.
Self-weight and transverse loads may induce shear/moment distributions in the member.
Member loads are lumped at each end, whereas a frame member with moment releases only retains the axial component of the applied member load.