The correct answer is D. Triangular load + load from the roof.
The lintel is to be designed for the self weight of the lintel, the triangular load of the wall above the opening, and the load from the roof. The triangular load is due to the weight of the wall above the opening. The load from the roof is due to the weight of the roof itself and any other loads that may be applied to the roof, such as snow or wind loads.
The triangular load can be calculated by multiplying the length of the wall by the height of the wall above the opening and dividing by 2. The load from the roof can be calculated by multiplying the area of the roof by the live load and dead load.
The lintel must be designed to support the combined load of the self weight of the lintel, the triangular load of the wall, and the load from the roof. The lintel must also be designed to resist the bending moment and shear force caused by these loads.
The following is a brief explanation of each option:
- Option A: Triangular load of the wall. The triangular load is due to the weight of the wall above the opening. The load can be calculated by multiplying the length of the wall by the height of the wall above the opening and dividing by 2.
- Option B: UDL of wall. The UDL of the wall is the uniform load due to the weight of the wall. The load can be calculated by multiplying the length of the wall by the width of the wall by the unit weight of the wall.
- Option C: UDL of wall + load from the roof. This option is incorrect because it does not include the triangular load of the wall.
- Option D: Triangular load + load from the roof. This option is correct because it includes the triangular load of the wall and the load from the roof.