Here are some design notes when it comes to modern pergola designs. The most common pergola design is to have decorative and somewhat rounded ends on the beam. The easiest way of creating a more modern pergola is to do away with the decorative ends.
14 wide x 28 long with an 8 overhang. The gambrel (barn style) roof maximizes storage space on the upper level. Plenty of room inside - 8 clearance on the lower level. 7 6 of overhead clearance on the second floor!