Embed Size (px)
Citation preview
Validation of Non-linear FEA Methods for Concrete Dams
October 3, 2017
Mark Schultz, SE, GE Supervising Engineer
CA Division of Safety of Dams
• Professor Chopra’s Influence on Seismic Analysis of Concrete Dams
• Application of Design Ground Motion
• Two Case Studies - System Response to EQ
• Nonlinear Materials & Interface Contacts
2 Chopra Symposium – Validating Nonlinear Analyses
Overview
3 Chopra Symposium – Validating Nonlinear Analyses
Idealized 3D Dynamic System
• Theoretical Basis of Analyses • Dam-specific FEA Software
• EAGD 2D-84 • ADAP-88 (Interaction between Monoliths) • EACD 3D-96 (Updated 2008) • SCADA (Smeared-Crack Approach)
• Chart & Equation Methods
4 Chopra Symposium – Validating Nonlinear Analyses
Research Deliverables
5 Chopra Symposium – Validating Nonlinear Analyses
Commercial Nonlinear Software
Absorbing Boundaries -Simulate unbounded domain -Absorb reflected wave
Reflected Wave Earthquake
Dam-Reservoir Interaction
Dam-Foundation Interaction
• Mass Foundation w/ Wave Propagation • Spatially Varied Ground Motion • Unbounded Domains – Nonreflecting Boundaries • Reservoir Hydrodynamics & Water Compressibility • Interface Contacts
• Dam-Foundation • Dam-Reservoir • Monolith-Monolith
• Material Softening & Load Redistribution
6 Chopra Symposium – Validating Nonlinear Analyses
Non-uniform Ground Motion
Earthquake
Reflected Wave
Response Varies Along Dam-Abutment Interface
7 Chopra Symposium – Validating Nonlinear Analyses
Application of Ground Motion
Full Model Free-Field Box Model
Input Design Motion (GMPE) Based on Level Terrain
8 Chopra Symposium – Validating Nonlinear Analyses
Frequency Domain Scaling
Free Field Model
Initial Base Input = Target Record
Computed Free Field ≠ Target Record
9 Chopra Symposium – Validating Nonlinear Analyses
Frequency Domain Scaling
Free Field Model
Initial Base Input = Target Record
Computed Free Field ≠ Target Record
10 Chopra Symposium – Validating Nonlinear Analyses
System Response Validation
11 Chopra Symposium – Validating Nonlinear Analyses
LS-DYNA 3D Model
12 Chopra Symposium – Validating Nonlinear Analyses
Matched Recording at Toe
13 Chopra Symposium – Validating Nonlinear Analyses
Matched Recording at Toe
14 Chopra Symposium – Validating Nonlinear Analyses
Crest Comparison
15 Chopra Symposium – Validating Nonlinear Analyses
Pacoima Dam
Ground Motion Applied
Measured Toe Recording
16 Chopra Symposium – Validating Nonlinear Analyses
Pacoima Dam
Monolithic Dam Model
Northridge EQ
17 Chopra Symposium – Validating Nonlinear Analyses
Pacoima Dam
Monolithic Dam Model
Northridge EQ
18 Chopra Symposium – Validating Nonlinear Analyses
Pacoima Dam
Model With Vertical Joints
19 Chopra Symposium – Validating Nonlinear Analyses
Pacoima Dam
2.0 in
Displacement Scale Factor = 100
20 Chopra Symposium – Validating Nonlinear Analyses
Effective Seismic Input Method
21 Chopra Symposium – Validating Nonlinear Analyses
Fluid Element Calibration
G.W. Housner Model (1954) LS-DYNA Model
22 Chopra Symposium – Validating Nonlinear Analyses
Nonlinear Concrete Material
23 Chopra Symposium – Validating Nonlinear Analyses
Nonlinear Concrete Material
Realistic Hysteresis Loops Realistic Load Capacity
Implementing Nonlinear Analysis for Dams and Soil-Structure Interaction 24
Lab Test Validation
25 Chopra Symposium – Validating Nonlinear Analyses
Concrete Cracking Model
397 psi
Time = 5 sec Time = 12 sec
M5
26 Chopra Symposium – Validating Nonlinear Analyses
Dam-Foundation Interface Merged
27 Chopra Symposium – Validating Nonlinear Analyses
Dam-Foundation Interface
Unmerged
Merged
28 Chopra Symposium – Validating Nonlinear Analyses
