Which of the following is NOT a method of permanent bracing used for steel wall frames?

Permanent bracing is crucial in maintaining the stability and structural integrity of steel wall frames. Each of the methods listed, except for the one identified, serves a purpose in ensuring that the structure can withstand lateral forces, such as wind or seismic activity.

Structural sheathing, often made from materials such as plywood, provides stiffening and helps prevent racking, thereby adding to the frame's overall strength. This method is recognized for its effectiveness in connecting and stabilizing the wall frame.

X-bracing is a widely accepted method that involves placing diagonal braces in a cross pattern. This arrangement effectively distributes loads across the frame and helps prevent deformation under stress.

Horizontal bracing contributes to stability by connecting two points on the frame horizontally, offering resistance against lateral forces. It plays an essential role in maintaining the shape of the structure during challenging conditions.

On the other hand, vertical bracing, while important in certain contexts, is not typically classified as a method of permanent bracing for steel wall frames. This is because vertical braces primarily bear vertical loads rather than providing the necessary lateral stability that is critical for bracing systems. Therefore, it does not serve the same function as the other methods listed, which are specifically designed to combat lateral loads.