Salinas
Dam is a concrete arch structure located on the upper Salinas
River near town of Santa Margarita, California. The dam is of
unusual design and was constructed with great speed in 1941. It
consists of a thin arch structure, left and right thrust blocks,
service spillway on the right abutment, overflow spillway along
the arch dam crest, and three concrete struts to stabilize the
right abutment. The arch structure includes four vertical contraction
joints with a peripheral joint that separates the arch from footing
and thrust blocks. All joints include shear keys.
The
stability of Salinas Dam is being assessed using linear and nonlinear
three-dimensional (3D) finite-element analyses for static and
seismic loading conditions. The 3D finite-element model includes
the arch dam, gravity thrust blocks, foundation rock, and the
impounded water. In addition, the nonlinear model also includes
nonlinear joint elements to account for opening and closing of
the vertical contraction joints and cracking/opening of the lift
lines as well as the dam-foundation interface joint.
As
a subcontract to URS Corporation, Quest Structures has developed
performance criteria for the nonlinear analyses and is performing
a series of 3D nonlinear time-history analyses including parameter
sensitivity studies. The parameter sensitivity studies are conducted
to determine the optimum joint configurations that would best
capture the nonlinear behavior and joint opening mechanisms. Sensitivity
of the nonlinear behavior to characteristics of earthquake ground
motion is being investigated by performing several nonlinear response
analyses using different earthquake acceleration time histories
that will be selected to represent a wide range of ground motion
characteristics.
