Counterfort

A buttress bonded to the rear of masonry walls. Counterforts were designed to improve the stability of masonry walls, increase their resistance to rapid breaching, and make subterranean demolition more difficult and time consuming. Counterforts were generally positioned at intervals along the rear of walls intended as revetments to improve the walls' resistance to the weight of the earth composing the rampart and to better bond masonry walls with the rampart. Counterforts were sometimes used to improve the standing strength of detached walls (walls that were not required to sustain the weight of a rampart) while minimizing the quantity of masonry required to construct walls.

Counterforts were generally given two basic forms: piers (or pillars) and arches. Piers were usually used to support revetment walls that sustained the weight of earthen ramparts while arches were generally used for detached walls. Piers were usually given a trapezoidal plan with the longer of the two parallel sides bonded to the rear of the wall. Arched counterforts could either be circular or elliptical with abutments in the form of rectangular piers. In either case counterforts could be carried to the full height of walls or cut off at whatever altitude below the full height was judged sufficient to meet the requirements of stabilizing and strengthening a particular wall.

January, 2003

August, 2005