Evolution of geotechnical risk analysis in North American practice - Risk and Reliability in Geotechnical Engineering - page 473

A new approach to analyzing flow-control systems is needed. The awareness of this need
is not unique to dams, hydropower, and large water management structures but has been
recognized with respect to many safety-critical technical systems. The simulation frame-
work involves four parts: (1) Simulation by which stochastic reservoir inflows are generated
and propagated through the river-reservoir-spillway-outflow system; (2) physics of failure
modeling to infer the impact of spillway heads and discharges on the hydraulic structures
accommodating outflows; (3) component reliability analysis to ascertain the performance of
individual components of the outflow works; and (4) systems reliability assessment through
which demands of the river system and performance of flow-control systems components
coupled with interactions of humans are convolved into annual exceedance probabilities of
adverse performance.

12.9.2 Stress testing and scenario analysis
Stress testing and scenario analysis is a concept that has arisen out of system failures in other
arenas, for example, in seismic performance of buildings or in the response of the financial
system to disturbances. It remains an evolving concept in geotechnical applications but is
receiving attention in natural hazards assessments (Short 2013), particularly in cases involv-
ing low-probability high-consequence events ( Figure 12.8 ) .
Stress tests attempt to determine the load under which a system as a whole fails and how
it fails, and whether cascading failures are important to systems performance. The overall
system is hypothetically loaded by a catastrophic hazard, and as the loading continues, the
response of the individual system components and their interactions is tracked. The goal is
to understand the systems behavior during an extreme event and the modalities of its degra-
dation (Lacasse and Nadim 2011).

e Panama Canal
Principal components

Gatun Locks

Madden
Lake

Gatun
Dam

Atlantic

Madden
Dam

Gatun
Lake

Pedro Miguel
Locks
Miraflores
Spillway

Gaillard Cut

Miraflores Lake
Miraflores Locks

Pacific

Figure 12.8 The principal infrastructure assets of the Panama Canal Authority. (From Alfaro, L. 2013. The
Expansion of the Panama Canal _ in the Context of the Canal's History , February 22. West Lafayette:
Purdue University.)