Design decisions and target reliability

Design decision orchestration and low-level decision helpers.

Import the object API below from pystra.decision. Implementation responsibilities are separated into swtp, targets, risk, objectives, criteria, studies and plotting modules; ddo composes the studies, objectives and criteria.

DesignStudy.run() returns a structured snapshot. Its table adapter retains failed alternatives and diagnostics; DDO excludes those alternatives from selection.

SWTP	Societal willingness to pay per statistical life.
FatalityConsequence	Expected fatalities conditional on structural failure.
LQI	Minimum acceptable life-safety criterion using LQI/SWTP.
TargetReliability	Target failure probability and reliability index from a calibration.
CostBenefitModel	Cost-benefit objective for a reliability design study.
DesignStudy	Evaluate a reliability callback over a one-dimensional design range.
RiskStudy	Evaluate a risk model over design alternatives.
ScenarioRiskModel	Scenario-table risk model for aggregated risk studies.
RiskResult	Expected annual risk quantities for a component or scenario model.
DDO	Evaluate a decision context with an objective and acceptability criterion.
DDOObjective	Base interface for DDO objectives.
DDOCriterion	Base interface for DDO acceptability criteria.
RackwitzTargetModel	Rackwitz/Steenbergen target-reliability model for code calibration.

The low-level helpers and record types below back the object API. They remain importable from pystra.decision.ddo for direct reproduction of the JCSS/LQI equations, but the object API above is preferred.

lqi_k1	Return the LQI safety cost ratio K1.
lqi_target_reliability	Return an LQI target reliability for a safety cost ratio.
derive_lqi_target	Calculate an LQI target from the marginal optimization condition.
rackwitz_table	Calculate the default Rackwitz/Steenbergen target-reliability table.
jcss_lqi_risk_cost	Return the JCSS LQI life-safety risk cost.
jcss_lqi_risk_cost_from_result	Return JCSS LQI risk cost from an aggregated risk result.
jcss_lqi_acceptability	Return the finite-difference JCSS LQI acceptability margin.
jcss_lqi_acceptability_margin	Return the JCSS marginal LQI acceptability margin.
jcss_lqi_is_acceptable	Return True when the JCSS marginal LQI condition is satisfied.
jcss_systematic_reconstruction_objective	Return the JCSS infinite-horizon reconstruction objective.
present_value_factor	Return the JCSS-style present value factor for a constant annual flow.
annualized_safety_cost	Return the annualized safety cost used by the JCSS LQI example.
finite_difference_derivative	Return a central finite-difference derivative for a scalar design.
lognormal_ratio_failure_probability	Return P(R - S <= 0) for independent lognormal resistance and load.
plot_summary	Plot a one-dimensional design decision optimization summary.
TargetReliabilityCalibration	One-dimensional calibration for deriving a target reliability.
get_swtp	Return the SWTP value per statistical life for a country code.
get_swtp_record	Return a country-level SWTP record.
get_swtp_index_record	Return the SWTP index record for a country code.
index_swtp_record	Return a Rackwitz SWTP record indexed to a newer target year.
swtp_table	Return the built-in country SWTP table as a dataframe.
SWTPRecord	Country-level societal willingness-to-pay value.
SWTPIndexRecord	Index data used to update an anchored SWTP value.

Use it: Comparing structural assessment scenarios · Steel-bar design decisions and LQI acceptability · Design decisions and societal risk