Product(s):	SACS
Version(s):	All
Area:	SACS IV

Problem

How SACS define the local X, Y and Z axis?

Solution

The default member local coordinate system is defined as:
1. The member local X-axis is defined along the member neutral axis from the first connecting joint specified toward the second connecting joint.

2. For members that are not vertical, i.e. local X-axis is not parallel to global Z, the local Z-axis is defined as perpendicular to local X-axis, lying in the plane formed by the global Z and local X-axes and having a
positive projection along the global Z-axis. The right-hand rule is used to determine the local Y-axis.

3. The local Z-axis for vertical members, i.e. members whose local X-axis is parallel to global Z, is parallel to the global Y-axis and in the positive Y direction. The local Y-axis is determined by using the right-hand rule.

See figure below:

Member Local Coordinate System

Problem

Solution

See Also