Reliabilityffdeefghggrhrhhvrghgferg .pptx

how to make reliable

1. Reliability assessment

2. First set different acceptable levels of performance (parameter Y at predefined X) Measure the Y-parameter with varying X-parameter Do a statistical analysis and determine the “median” and lognormal standard deviation” Example: median and standard deviation calculation Slight Moderate Collapse Prevention 0.4 0.48 0.483 0.46 0.52 0.55 0.495 0.57 0.57 0.5 0.61 0.61 0.845 0.846 0.846

3. Fragility function is a probabilistic tool being used to estimate the likely damage to occur during a seismic event. Probability that the expected global damage of a structure exceeds a predefined damage state, d si , as a function of a parameter quantifying the severity of the seismic action. Reliability index can be expressed as β=- * inverse std normal (p f ) ^-1 is the inverse standardized normal distribution .  

4. Using the median and lognormal standard deviation, derive fragility curves using the formula: Pf = median(Y)*e^(standard normal quantile)

5. Once you determine, Pf , go to probability of failure and reliability table (see attached table)