Seismic Performance in Urban Regions (SPUR): A Simulation Example

Roger L. King

Tomasz Haupt

Mississippi State University

Gregory L. Fenves

University of California, Berkeley

Jacobo Bielak

Carnegie Mellon University

Joerg Meyer

University of California, Irvine

NSF NEES Awardees MeetingSeptember 11-12, 2003

Outline of Presentation

• Roots of project• What is SPUR?• Value of integration• Structural performance• Earthquake ground motion modeling• City response• Visualization• SPURport – web portal• Future plans• SPURport demo

An NSF ERC Problem Centered Research Flow Process

SPUR, a Distributed Simulation Framework for Seismic Performance for Urban Regions

• Advance the state-of-the-art in simulating the effects of a major earthquake on an urban region.

• Integration of earthquake ground motion modeling with modeling of structural and infrastructure systems using advanced computational and visualization methods

• Shift focus from a discipline specific approach to a problem centered approach.

SPUR, a Distributed Simulation Framework for Seismic Performance for Urban Regions

• A distributed interactive simulation framework will be created to facilitate investigation of the performance of urban regions resulting from a major earthquake and for the education of future earthquake engineers.

• The goal is to develop tools that will ultimately permit damage estimates based on best available information.

• This can lead to earthquake related risk analysis/assignment for an urban region and to provide a rich problem solving environment for the education of students.

PBEE

SSFI

Basin Effects

Large Scale Viz

Fundamental Research• Computational seismology• SSI with DRM• PBEE Performance measures• Spatial distribution of performance• Large scale viz.

Enabling Technologies• Archimides• OpenSees• NEESgrid• System integration

Middleware

NEESHPC Resource

Viz

Systems-level Applications• Loss estimation• Tools for decision makers• Scenarios for planning

MicrozonationPlanning

Emerg. Resp.Education

Loss Estimate

SPUR Strategic Vision

System Architecture

ground motion data

(CMU)precomputed simulations

ground motion data

(CMU)precomputed simulations

rendering + portal(UCI) (MSU)

immersive rendering &web-based portal

rendering + portal(UCI) (MSU)

immersive rendering &web-based portal

structural response

(Berkeley)precomputed or online

simulations

structural response

(Berkeley)precomputed or online

simulations

SPURport: The Grid based portal for SPUR

• Provide earthquake community with collaborative environment for research on Seismic Performance of Urban Regions and training of future earthquake engineers.

• Develop NEESgrid application of databases, computation, visualization, using distributed Grid-accessible resources; demonstrate ability to use NEESgrid resources at any location

• Opportunity to apply NEESgrid software releases to a substantial application and provide NEESgrid developers feedback

• Add to simulation capability of NEES

SPURport Prototype

• Development begun summer 2003

• Design and rapid prototyping iterations

• Extensible as SPUR functionality increases and NEESgrid matures

• Coordinate future SPURport development with NEESgrid roadmap

Strike slip Fault Simulation ModelPeak Ground Displacement

Peak Ground Velocity

Thrust Fault Simulation ModelPeak Ground Displacement

Peak Ground Velocity

Structural Models for Regional Simulation

ObjectiveEvaluate regional distribution of Engineering Demand Parameters (EPD)SDF Model u

u

u

uu

u

u

u

Grid point

- “Hydra” model- Multiple parameters and multiple orientations- Constant strength analysis- Constant ductility analysis

Simulation Tool – OpenSees (PEER software framework for simulation)

Building Models

ShearBeamModel

GeneralizedFrameModel

BuildingModels

Constant Ductility Analysis for Strike Slip Fault

Constant Ductility Analysis for Thrust Fault

SAC 9 story OpenSees Model

Column Fiber Section

Beam Fiber Section

Leaning columnsfor P- effects

Distributed Plasticity Beam-Column

LA 10%/50 year

Regional Distribution of SAC 9 story EDP

Roof drift ratio

Max Plastic Rotation

Max Story Drift Ratio

PGV

Regional Distribution of SAC 20 story EDP

Max Plastic Rotation

Roof drift ratio

Max Story Drift Ratio

Story 22

Story 15

PGV

Calibration of Shear Beam Model

Pushover Analysis of Frame Model Shear Beam Model

Story Force-Deform.

Calibration of Generalized Frame Model

SAC 9-story Building

All rotations at joints lying at each floor level are identical

Mpi

Myi

MBi

KBij = 6EIBij/Lj

MBi = KBi i

KBi = 2KBij

Mpi = 2Mpij

i

Rotational Spring

Column

KCi = KCij

M

Column is modeled using elastic beamwith plastic hinge with hinge length

Comparison of Floor Displacement

Generic Frame Model

Floor 1 Floor 2 Floor 3

Floor 1 Floor 2 Floor 3

Shear Beam Model

Comparison of Story Drift

Generic Frame Model

Story 1 Story 2 Story 3

Story 1 Story 2 Story 3

Shear Beam Model

Regional Distribution of EDP, 3-Story

Roof Displacement

SAC Frame Model Shear Beam Model Generic Frame Model

SAC Frame Model Shear Beam Model Generic Frame Model

Max Story Drift

Computational Challenge

SAC 9-Story Simulation– 306 DOFS, 1800 time steps.

– Approx 4 min. per grid point.

– 25,281 grid points.

– 70 days in single processors.

Constant Ductility Analysis– 28 parameter combinations.– Considering 8 orientations.– 25,281 grid points.– 5 iterations in average.– One million non-linear analysis

of SDF system per parameter.

Parallel Computation Approaches• Use MPI in distributed memory system (e.g. Linux cluster).• Dynamic load balancing essential for even finish time with various

load conditions on multiple processors.• Two approaches developed for hardware architectures and regional

simulation problems.

Producer-Consumer Approach

Parent nodes

Child nodes

NFS servers

dataresult

Master node

work size

dataoutput

NFS servers

data

output

Steal work load

Steal work load

Steal work loadSteal work load

Stealer Approach

OpenSees Applications for Parallel Computing

Parallel simulation applications built with OpenSees API and MPI API can be implemented using NEESgrid resources.

Model Domain

Element Material Pattern

Analysis Solution Procedures

OpenSeesFramework

wake

Packaging Send output

wait

Un-packaging

Receive Ground Motion

Structure parameter

Slave Node

Job Queue

Wait Queue

Ground Motion Data

Recording output

Receive outputUn-packaging

SendGround Motion

Structure parameter

pack

agin

g

ProcessManage

Master Node

Producer-Consumer Approach

Northridge Earthquake mainshock

(USGS)(USGS)

Rupture Model

Dep

th (

km

)

Wald et al. (1996)Wald et al. (1996)Strike=122 (S58E), Dip=40 (S32W), Rake=101Strike=122 (S58E), Dip=40 (S32W), Rake=101

USGSUSGS

Rupture propagation (velocity)

Snapshots of surface velocity

Peak ground velocity Peak ground velocity ((USGS)USGS)

Verification against other

codes

-Graves (URS)

- Archimedes -Quake

IDEALIZED MODELCross Section

Reduced Domain

Cascading (3 models)

FREE FIELD RESPONSEPeak values of displacement and velocity

Analysis Region

Observation Point(1280, 3000)

Observation Point

Velocity (m/s)

|FT|

Peak Ground Velocity in Region of Interest

Vm

ax

800 m/s

100 m/s

200 m/s 40 m

Random City Model

FEM BIM LAYOUT

Influence Of Different Structural Distributions On Maximum Ground

Velocity (EW)

Free-field 3 1.0-Hz Buildings R-City

Notation for SSI

57

44

SSI Analysis of Three Building Groups for the R-City Simulation (EW Displacement)

Maximum Velocity Response

1.0-Hz City buildings 2.0-Hz City buildings R-City buildings

EW

NS

Random City Simulation(launched through SPURport)

VisualizationNew Algorithms:• TetFusion

• Efficient 3-D mesh decimation• More efficient than edge-collapse• Various levels of detail• Controlled Fusion

• Metric 1: local scalar attribute error• Metric 2: accumulated scalar error

• QTetFusion• QuadMetric:

• Metric 3: topology preservation

SPURport Architecture

Tele-presence

NEESpop (middleware)

MSU extensions(Enterprise Computational System)

ApacheTomcat

JetSpeedChef

NEESgrid services

DBMS(postgress)

EJB container(JBoss)

OGSI(globus 3.0)

ECSapplicationstreaming

device driver

Data Controller

Data streaming andchannel management

Authentication andauthorization

SPURapplet

Request

Data

NSDS

Data andMetadata

Collaboration

ERCat Mississippi State PSC NCSA

OpenSees OpenSeesGround Motion

DataStruct. Resp.

Data

Ground MotionData

Front End

Back End

SPURport Data Objects

EQVolumeData

GroundMotionData

RegionalSimulation

StructModel PopulationMethod(inventory)

Spatial Quantity

SpatialResponseData

EQModel

association (has a ….)

composition (contains a ….)

SPURport functionality

EarthquakeModel

Inventoryof Structures

view data

extract data

StructureModel

select or definea structure

(set parameters)

select location

run simulation

select or definean inventory

run simulation (future)

view data view data

Earthquake model

Structural Model

Population Method

Spatial Response Data

Individual Structure Response

Future Plans• System level V&V (understand limits)• Create building inventory (Variable building

types)• Structural performance of this inventory

during 1994 Northridge earthquake• Soil Structure Foundation Interaction during

1994 Northridge earthquake• Other structures (highway bridges, etc.)• Create 4D visualization toolkit for use with

PCs• Improved texture-based volume rendering• Make SPURport available to community• Initiate interactions with FEMA and HAZUS