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Definition and Offsets
A shear line consists of one or more parallel shear walls that act as one to resist an applied shear load. Walls can be on the same shear line as long as they are separated by no more than the maximum shear wall plan offset if on the same level, and the maximum shear wall elevation offset if they are on different levels. These values are set in the Design Settings.
None of the design codes and standards implemented in the program recommend a shear line offset, as shear walls are expected to be at the same location if they are to act as a unit. However, a default 6" (150 mm) plan offset has been implemented to provide tolerance for automatic shear line generation.
Shear Line Generation
Shear lines are automatically generated by the program as walls are created and moved about. If a shear wall can belong to more than one shear line that has been automatically generated, you can move the shear wall from one line to the other in the Wall and Shear Line Input Form.
A bandwidth approach is used to automatically generate the shear lines. The bandwidth is the allowable offset. For North-South shear lines, the first wall encountered becomes the left limit of the first shear line's bandwidth. Any wall found within the bandwidth is considered to be on the shear line. The next shear line starts at the first wall found beyond the previous shear line's bandwidth.
Shear Line Extent
A shear line may contain gaps or non-shear wall components, even at the ends of a shear line. On a particular building level, shear lines start and end at the perpendicular perimeter walls of the building. The shear walls along the shear line may not extend as far as the shear line itself; in this case, it is assumed that the walls on the shear line are tied in to the perimeter perpendicular walls by means of drag struts.
If the shear line runs into the perimeter walls at a point where those walls are offset, it extends as far as the closest perpendicular perimeter wall if the connecting wall in the offset (along the shear line) is a non-shear wall. It extends to the furthest perimeter wall if the connecting wall is a shear wall.
Display
When you select a wall to edit or to load in Plan View, all walls on the shear line are highlighted in a brown colour, and the individual selected wall is in orange.
After a design is run, walls that do not pass design for the load case shown on the screen (rigid, flexible, wind, seismic) are highlighted in red. A selected failed wall is in a darker color of red.
If you select a shear line, then go to Elevation view, all walls along that line appear on the screen.
The first digit of the names of the walls along the shear line indicates the shear line name. East-West shear lines are designated by letters of the alphabet, and North-South shear lines by numbers. Thus A-1, A-2, A-3,...,B-1, B-2, B-3,... are East-West walls, and 1-1, 12, 1-3, ...,2-1, 2-2, 2-3 are North-South walls.