Seismic Structural Analysis of Bartlett Dam (Multiple Arch Dam), Phoenix, AZ

Bartlett Dam is a 287-foot high multiple arch and buttress dam, 48 miles northeast of Phoenix, Arizona on the Verde River. Construction was completed in 1939. The upstream arch barrels are 24-ft radius half cylinders varying in thickness from 7 ft at the base to 2 ft at the crest and sloping 42 degrees off horizontal. The buttresses are two walls separated by a vertical 8-foot hollow space from base to crest. The exterior walls vary in thickness from 2 feet at the crest to 7 feet at the base. Vertical 18-inch thick stiffener walls spaced 20 feet apart span the hollow core between the exterior walls. The dam will be raised about 21.5 feet to accommodate the probable maximum flood (PMF) reservoir level. Options considered for raising the dam from the current elevation of 1799.5 ft to elevation 1821.0 ft were a straight vertical wall and slab system, a scalloped vertical wall following the curvature in plan of the arch barrels, and extending the arch barrel cylinders along the original geometry. Dynamically, the integrity of the arch barrels is vulnerable as the massive buttresses bend in the cross-canyon direction and impinge on the arch barrels. This paper will present the dynamic structural analyses for the maximum credible earthquake (MCE). 6 pp., 5 references.