Many of you have never heard the term structural bunker. There apparently are no references to it in any golf writings.
The basic types of bunkers are directional, penal, and saving. Any of the bunker types could be strategic or structural. The strategic bunker is obvious and needs little discussion but the structural bunker is another story. Structural bunkers, which are virtually unknown and ignored are used to deal with elevation changes and to minimize earth moving. Any one bunker can be combinations of different bunker types. One bunker can tell you where to hit the ball, directional, save you from running away into trouble, saving, and then after you are in it penalize you with a difficult shot. It can also be structural in that it handled a change in elevation during the construction process instead of requiring more fill or a wall of some sort.
This is a picture of Sagebrush Golf and Sporting Club's 3rd hole. The big fairway bunker on the left was utilized strategically to cause the golfer to think about the dangers on the left side of the hole. It is also the support for a 15 foot fill. As natural looking as it is, its completely man made and allowed us to minimize the fill required to deal with the hole's significant right to left slope. If a structural bunker had not been used the required fill and tie-in would have been substantial and a bit of a force. The look and story from the tee would have been very different. This was a balanced cut and fill. The bunker generated the fill required to achieve the elevation change. This is an aesthetically appealing, golfer friendly, cost effective, solution to one of golf course architecture's challenges.