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Monticello Blind Prediction WorkshopUSSD EARTHQUAKES COMMITTEEAPRIL 2016

340-ft tall medium arch Earthquake recorded on May 22, 2015

Epicenter 16 km away from the dam

4.1M ground motion

Material Testing

Static Compression: 3080-5820 lb/in2

Dynamic Compression: 3640-5570 lb/in2

Static Direct Tension: 55-245 lb/in2

Static Split Tension: 260-425 lb/in2

Dynamic Split Tension: 230-595 lb/in2

Static Modulus of Elasticity: 4.12-7.18x106 lb/in2

Dynamic Modulus of Elasticity: 3.00-6.68x106 lb/in2

Eccentric Shaker Test

Ground Motion

Ground Motion Response Spectra

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Acc

eler

atio

n (g

)

Period (seconds)

Response Spectrum

EW NS VERT

Prediction Assumptions

Upstream/Downstream Displacement Predictions

Cross-CanyonDisplacement Predictions

Upstream/Downstream Response Spectra

Cross-Canyon Response Spectra

Questions for Discussion Given the information provided, what is the ideal analysis

methodology? Multiple? What boundary conditions are appropriate? Could there have been considerable impacts of resonance on the

instrument? What model assumptions are subject to the greatest uncertainty in

this analysis? What other data or assumptions would have been needed to

improve the blind predictions? What conclusions can we draw from the presented responses for

future predictions of dam response? Do these predictions provide enough confidence to make decisions

informed by finite element analysis? How do we do better?