02315 - Interior view of Fort Sumter; Charleston, South Carolina, April 1865 [LC-DIG-cwpb-02315]
After Fort Sumter fell to Confederate forces in April of 1861 it became a stronghold of the Confederacy. Within two years though it was back under attack by Union forces. With repeated shelling much of the defenses had eroded, which would have left the fort vulnerable.
To compensate gabion walls were used to replace or repair damage from the shelling. Gabions comes from the Italian word gabbione which means “bird cage”. Leonardo da Vinci had used gabions a few hundred years before to reinforce medieval castles and the practice continues to this day.
Essentially a wicker basket was made and then filled with rocks, dirt and sand. By doing this you could quickly rebuild or reinforce a structure allowing it to still operate effectively as a fort. By using local material you could easily re-use the rubble from the shelling to still provide effective walls. You could even use this to multiply the thickness of existing walls and further enhance the fort.
As shown in this image the gabions can be extended vertically as well as horizontally allowing you to quickly grow walls several stories tall. Today gabions are typically made with a wire or plastic mesh. The use of these is not only seen in military applications today, but also can be found along highways and roadways allowing long lasting protective walls to be made for anything from falling rocks to supporting the road deck.