Ruins Stabilization in the Southwestern United States
Publications in Archeology 10
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Appendix 2A

Figures 62-64 are facsimilies of the stabilization record on wall realignment and the use of adobes for repair concealing integral reinforcement at Fort Union National Monument. These and similar forms for first and second sheets, and a sheet for attachment of photographs of ruins before and after stabilization, are in use at the National Park Service archeological center in Tucson.

Case Grande Ruins National Monument, Coolidge, Arizona. This site is the famous Compound A which contains the Casa Grande, or Big House, with its associated structures and refuse mounds. The Casa Grande, a massive walled structure containing three usable stories, was built of coursed caliche-earth, a desert soil with a high lime content. Recent stabilization methods (after this photograph was taken) consisted of either forming or veneering the low compound walls surrounding the Big House with soil cement, and treatment with water repellent silicones.



Fort Union National Monument; Date: July 14, 1960; Building: 3-330; Room: 331; Feature: wing wall; Wall (N.S.E.W.): E S W.


Orientation, plan and type (situation, evidence of additional stories, period of construction relative to surrounding rooms, evidence of burning, etc.): Contemporaneous with contiguous rooms. No evidence of burning. Single story.

Floor (floor type; additional notes): Probably packed earth.

Details (notes on doorways, lintels, etc.): Brick coping atop wing wall ready to fall. West wall is also the east wall of room 321. Little remains of east wall; almost none of north wall standing. Foundation stones missing from wing wall on east end.


Room No. 3-331; Date work started: Sept. 4, 1958; date work finished: May 12, 1959; Man days of labor: 28-1/4; Cost of materials: $160.08. Archeologist: Rex L. Wilson; Date: July 14: 1960.

Condition on date work started; masonry: All walls need capping. Brick coping in urgent need of reinforcement. Adobes badly eroded away under coping in wing wall.

Materials, construction, and technique in making repairs or accomplishing job: Wing wall: Missing foundation stones were reset in cement mortar. After the brick coping had been realigned with mine jacks, a grid work of angle iron was placed on the north side of the wall and welded to a smaller gridwork of angle iron placed at a right angle to it on the east side of the room's east wall. The larger gridwork consists of four 11' 8" lengths of 2" x 1/8" angle iron placed vertically on the north side of the wall in intervals of 4' 9", 4' 4", and 5' 1". The westernmost vertical member is situated in the angle formed by the abutting walls.

A collar of 2" x 1/8" angle iron was welded together and placed immediately under the brick coping. It was then welded to the vertical angle irons. The collar is 15' 3" long and 2' 6" wide. Two 11' 8" lengths of 2" x 1/8" angle iron was placed horizontally and welded to the vertical members. The upper piece is 1' 3" below the underside of the coping and the lower piece is placed midway in the wall 5' 10" above the top of the stone foundation. Resting directly upon the stone foundation is a 11' 8" length of 2" x 1/ 8" strap iron which is welded to the vertical lengths of angle iron.

The entire gridwork is held to the wall by lengths of 3/8" reinforcing rod placed at various points on the gridwork. They penetrate the wall, are welded to the gridwork on the north side, and are welded to strap iron washers imbedded in depressions hacked out of the adobe on the south face of the wall.

A short length of angle iron is welded diagonally to the strap iron and to the westernmost vertical angle iron.

Another grid work is welded at a right angle to the extreme west end of the larger system. The smaller section is recessed in the east side of the abutting east wall of room 331. A single vertical 10' 5" length of 2" x 1/8" angle iron was placed 5' 11" north of the point where the east wall of room 331 abuts to the wing wall. The vertical member is welded to a horizontal 5' 11" length of 1-1/4" x 1/8" angle iron and to a 2" x 1/8" angle iron 5' 11" long. The uppermost horizontal piece (1-1/4" x 1/8") is situated 10' 5" above the top of the stone foundation and the other is placed 4' 7" below that. The vertical members are welded to a 5' 11" length of 2" x 1/8" strap iron resting upon the top of the foundation.

A final 6' length of 2" x 1/8" angle iron is welded diagonally from the angle iron placed in the corner formed by the abutting walls to the northernmost vertical member in the east wall of room 331.

After the completion of the steel installation a concrete cap was laid on top of the coping and painted red. Adobes were used on the east end and north side of the wing wall to conceal the steel gridwork and to further reinforce the wall. The new adobes were roughened to give the illusion of age. The wing wall was then sprayed with Dow Corning 129G Resin.

South, west, and east walls: Capped. Sprayed with Dow Corning 772 diluted in water at a ratio of 1 to 9.

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Last Updated: 16-Apr-2007