The correct answer is D. All options are correct.
Lug angles are used to reduce the length of connection. They are unequal angles, and they increase shear lag.
Lug angles are used to reduce the length of connection by providing a larger surface area for the bolts to engage. This increases the load-carrying capacity of the connection.
Lug angles are unequal angles because they are not the same size. The longer angle is called the “flange angle,” and the shorter angle is called the “leg angle.” The flange angle is typically twice the length of the leg angle.
Lug angles increase shear lag by providing a more rigid connection. Shear lag is a phenomenon that occurs in bolted connections when the load is not evenly distributed across the entire cross-section of the member. Lug angles help to distribute the load more evenly, which reduces shear lag.