Incremental Hybrid Simulation Development Method for Large Scale Application

(1)

Incremental

Hybrid

Simulation

Development

Method

for

Large

‐

Scale

Application

EU-US-Asia Workshop on Hybrid Testing

5-6 October 2015

Xiaoyun Shao, Ph.D., PE Associate Professor

Department of Civil and Construction Engineering Western Michigan University Kalamazoo, MI

(2)

Outline

• Background

– Hybrid testing in two NEESR projects

– Challenges associated with large-scale hybrid testing

• Incremental approach

– Developing hybrid testing methods

– Small-scale hybrid testing system

• Concluding remarks

(3)

Outline

• Background

• Incremental approach

(4)

1. NEES-Soft: Seismic Risk Reduction for Soft Story

Woodframe Buildings

PI : Dr. John W van de Lindt (Colorado State University )

Co_PIs : Dr. Weichiang Pang (Clemson University)

Dr. Xiaoyun Shao (Western Michigan University)

Dr. Michael Symans (Rensselaer Polytechnic Institute) Mikhail Gershfeld (California State Polytechnic University)

Objectives:

Experimentally

validate

•

4

economical retrofit concepts (FEMA P807)

•

3

performance-based seismic retrofits (PBSR)

Experimental program:

–

Full-scale slow PSD hybrid teting at NEES@UB

–

Full-scale shake table testing at NEES@UCSD

(5)

NEES-Soft Hybrid Testing

• Full-scale slow PSD hybrid testing @ UB-NEES facility

– Prototype: Full-scale three story residential building

–

Evaluate the performances of different retrofits with the

focus

on the

effects of the first story retrofits on upper stories

– Experimental substructure: • Upper two stories (full-scale) • Four actuators

– Translational & torsional

– Numerical substructure:

• First soft story with (4+3=7) various retrofits

(6)

NEES-RCFrame Project

2. NEESR: Near-collapse Performance of Existing

Reinforced Concrete Frame Buildings

PI : Dr. Mehrdad Sasani (Northeastern University)

Co_PI : Dr. Xiaoyun Shao (Western Michigan University)

Motivations:

• Collapse behavior requires system level analysis;

current criteria based on element failure

• Structures subjected to 3D earthquake loading

Goals:

• To determine the effects of triaxial as opposed to

unidirectional seismic ground motions on column failure and collapse mechanism

• To develop reliable analytical modeling tools and methods for collapse analysis

• To develop system level acceptance criteria and procedures for collapse analysis

Experimental program

– Geographically distributed hybrid simulation

(7)

NEES-RCFrame Project

(8)

Challenges in Large-Scale Implementation

• NEES-Soft: first full-scale woodframe hybrid testing

– Verification of integration algorithms and numerical substructure models

– Verification of hybrid testing controller

– Large-scale specimen (costly and time-consuming to repair)

– Limited onsite development time @ NEES facility

• NEES-RCFrame: large-scale geographically distributed

hybrid testing

– Verification of (internet) communication • between the two sites

• between OpenSees and UI-Simcor

(9)

Outline

• Background

• Concluding remarks

(10)

Incremental Approach

1. NEES-Soft: first full-scale woodframe hybrid testing

Small-scale  Mid - scale  Full-scale

Western Michigan Univ.

(11)

Hybrid Testing @

WMU

• Slow PSD

‐

HS controller

– Challenge: use a real‐time hybrid

testing system for slow testing

– Double ‐ trigger strategy

• Slow the test rate

• Accurate force reading

– Ramping loading pattern

• Real–time

PSD

‐

HS

controller

– Time‐delay compensation

• Smith’s predictor

• Feed-forward (polynomial extrapolation)

• Integration

algorithm

– Explicit Newmark

– Modified implicit Newmark

(adopted in NEESSoft project) – α‐operator‐splitting (α‐OS)

1st trigger, fixed step

(12)

HS Testing @

WMU

(13)

Hybrid Testing @

UA

• Slow

PSD

‐

HS

– Prototype structure

• Two-story stack wood shear wall frame

– Physical substructure

• First story shear wall

– Numerical substructure

• Second story shear wall

• Slow

HS

controller

– 20 times slow

– Integration step: 1/256 sec

– Real‐time controller step: 1/4096

sec

• RTHS

– Prototype structure

• Three-story

– Physical substructure

• First soft-story with and

without damper retrofit

– Numerical substructure

• Upper two story

• RTHS

controller

– Same integration and real‐time

controller step: 1/1024 sec – Feed‐forward delay

compensation

Transverse support Strong floor attachment

(14)

Hybrid Testing @

UA

(15)

Hybrid Testing @

UB

(16)

Hybrid Testing @

UB

• Phase 1: FEMA P807 economic retrofits

– Cross laminated timber (CLT)

– Distributed knee-braced retrofit (DKB)

– Inverted moment frame (IMF)

– Fluid viscous damper (FVD)

• Phase 2: Performance based seismic

retrofits (PBSR)

– Shape memory alloy (SMA)

– Steel moment frame (SMF)

– Direct displacement design (DDD) procedure

• Open-loop collapse RTHS

Shao, X., Pang, W., Griffith, C., Ziaei, E., and van de Lindt, J.W. (2015). “Development of a Hybrid Simulation

Controller for Full-Scale Experimental Investigation of Seismic Retrofits for Soft-Story Woodframe Buildings”

Earthquake Engineering and Structural Dynamics (under review).

Pang, W., Shao, X., Ziaei, E., van de Lindt, J.W., and Griffith, C., (2014). “Hybrid Simulation of Seismic Retrofits

for Soft-Story Wood Frame Building. Part II: Numerical Simulation Development” Earthquake Engineering and

Structural Dynamics(under preparation).

Jennings, E., van de Lindt, J., Ziaei, E., Bahmani, P., Park, S., Shao, X. Pang, W., Rammer, D., Mochizuki, G., and

Gershfeld, M., (2014). “Full-Scale Experimental Verification of Soft-Story-Only Retrofits Using Hybrid Testing.”

Journal of Earthquake Engineering (under preparation).

Jennings, E., van de Lindt, J., Ziaei, E., Mochizuki, G., Pang, W., Shao, X. (2014). “Retrofit of a Soft-Story

Woodframe Building using SMA Devices with Full-Scale Hybrid Test Verification.” Engineering Structures (under

(17)

Incremental Approach

2. NEES_RCFrame: Distributed Testing

Small – Scale

distributed

hybrid

testing

(18)

(19)

Small-Scale Hybrid Testing System @

WMU

• Size: 3 ft x 3 ft

• Max. specimen mass: 500 lb

(227kg)

• Max. acceleration: 4g • Max. displacement: ±3 in • Force: ±3240 lb at 3000 psi • Stroke: ±3 in

• Servo valve: 10 gpm at 1000 psi • Load cell: 2.5 kip

• 10 GPM HPS

• 380-480 V, 3 phase,

50/60 Hz power

• Local and remote

control, 24 VDC control voltage

• High/low pressure

controls

Hybrid testing model: programmed in

MATLAB/Simulink and deployed using NI-VeriStand LVDT • Stroke: 10 in • Power supply converter: 115 volts AC → 15 volts DC Accelerometers • Peak value: 4g • 3 axes Shore Western SC6000 • 2 channel, desktop enclosure • 2.13 GHz processor Chassis

• 8-Slot PXI-1050 Chassis Real-time processor

• 2.53 GHz Dual Core

PXI-8108 Embedded Controller DAQ • PXI-6229: 32 AI • PXI-6221: 16 AI Connector Block • SCB-68 Shielded I/O Connector Block

(20)

Outline

• Background

(21)

Concluding remarks

• NEES-Soft project

– Hybrid testing of a full-scale wood frame building was successfully

implemented to economically evaluate

7

different retrofits

• NEES-RC collapse project

– Geographically distributed test was performed

– (Implicit) Integration algorithm for complex numerical model and for

collapse simulation requires further development

•

Incremental approach

seems to be a

viable

and

(22)

Concluding remarks

Objectives

: accepting hybrid testing as a

primary

and

economic

testing method

• Process for planning and preparing

– Closely relate to the project objectives

– Validate at each preparing phase to ensure the functionality of each components (i.e. algorithms, controllers, specimen and hydraulic equipment)

•

Assess accuracy/stability

– Before/after test: numerical verification

(23)

Concluding remarks

Objectives

: accepting hybrid testing as a

primary

and

economic

testing method

• Model complexity

– Mostly shear-type building models for RTHS with nonlinear restoring force components

– Online model-updating

– Expand hysteresis model bank

– Using existing FEM analysis package

• Improve the acceptance

– Outreach to research communities (journal/conference papers, presentations)

– Share testing models online

– Prepare instructional documents (manuals, tutorials, etc.)

(24)

Acknowledgement

• Workshop organization committee

• My students: Chelsea Griffith, Griffin Enyart, Adam

Mueller, Chris Sawyer, Adnan Sanchez, Carlos Santana

，

Bilal Mohamed…….

• Collaborators in the two NEESR projects

• Staffs at WMU, NEES@UB, NEES@UIUC and the

Structural Engineering Laboratory @UA

(25)