The
Saluda Spillway Structure consists of six tainter gates supported
by five piers and the North and South Abutment walls. The piers
and abutment walls also support a six-span roadway bridge just
upstream of the tainter gates. The Gates 1 to 4 are located on
top of an ogee spillway which is keyed into Piers 1 to 4 and into
the North Abutment. The Gates 5 and 6 sections of the spillway
were added late with no spillway ogee and are located on top of
a 2-foot-thick concrete slab.
Quest
Structures was contracted to:
-
Review findings of previous studies conducted by others
-
Perform independent seismic assessment of the spillway structure
and gates
- And
if necessary, develop remediation schemes to:
- Keep
one gate operable after the design earthquake
- Permit
other gates to suffer damage but capable of retaining water
with acceptable amount of leakage.
The
work was accomplished in two phases. The focus of Phase-I efforts
was to assess earthquake performance of the spillway structure
using linear-elastic time-history analyses and to identify dominant
modes of nonlinear behavior (failure modes) for the Phase-II nonlinear
evaluations.
In Phase-II study the seismic performance was assessed by performing
nonlinear time-history analyses that incorporated the effects
of potential nonlinear mechanisms identified in Phase-I. These
included formation and propagation of tensile cracking at the
concrete-rock interfaces and within the concrete sections as well
as rocking response that could follow.
