When installing lateral and knee braces, what is their overall effect?

• A. They provide positive moments to the system
• B. They simply prevent rust
• C. They reduce system stiffness
• D. They increase weight without purpose

Answer: (A)

Lateral and knee braces are placed to stiffen the frame against lateral forces and to hold members from rotating during erection, effectively creating triangulation that resists sway. By carrying axial forces in diagonal paths, they restrain movement and transfer lateral loads into the structure and foundation, which adds positive resisting moments to the system. This increased stiffness and stability is the key benefit, not preventing rust, not reducing stiffness, and not adding weight without purpose.