Innovative Application of Damage Tolerant FRC Material for New Construction and Retrofit of Structures in Regions of High Seismic Risk Principal Investigators:

James Wight, Univ. of MichiganSarah Billington, Univ. of StanfordSherif El-Tawil, Univ. of MichiganGustavo Parra-Montesinos, Univ. of Michigan

Associated Investigators:Antoine Naaman, Univ. of MichiganTom Finholt, Univ. of MichiganJames LaFave, Univ. of Illinois at U-C

Sponsored by NSF

Components of the Project

Development of a HPFRCC Mix for field applications (Naaman, Parra-Montesinos)

Biaxial Tests of HPFRCC Specimens (El-Tawil, Parra-Montesinos, LaFave)

Testing of Isolated HPFRCC Coupling Beams at UM (Wight, Parra-Montesinos)

Testing of Isolated HPFRCC Infill Panels at UM (Billington, Olsen, Wight)

Components of the Project

FE Modeling of HPFRCC Specimens and Refinement of PSD Testing Protocol (El-Tawil, Billington, Olsen)

Testing of Coupled Wall Assemblies at UIUC (Wight, Parra-Montesinos, El-Tawil, LaFave)

Testing of Frames Infilled with HPFRCC Panels at UC-Berkeley (Billington, Olsen, El-Tawil)

EOT Programs at UM and Stanford (All PIs with special project from Finholt)

Development of Self-Consolidating High-Performance Fiber Reinforced Concrete

FRC – Fiber Reinforced Concrete HPFRCC – High Performance Fiber

Reinforced Cementitious Composite (exhibits tensile strain hardening)

SCC – Self-Consolidating Concrete (a highly workable concrete that can flow through densely reinforced elements under its own weight to fill voids without segregation or excessive bleeding and without the need for vibration)

Material and Mix ProportionMaterial and Mix Proportion

Fine AggregateFine AggregateCement, Pozzolan (FA)Cement, Pozzolan (FA)

φ= 0.5mm ; 0.38mmφ= 0.5mm ; 0.38mm l l = 30 mm= 30 mmAspect ratio = 80Hooked Fiber

MatrixMatrix Steel FiberSteel FiberCoarse AggregateCoarse Aggregate

Diameter < 3/8 inDiameter < 3/8 in

Cement Type 3

Fly Ash

SandCoarse

AggregatesWater SP VMA

SteelFibers

1 0.5 1.7 1 0.6 0.003 0.0095 0.244

Example: proportions by weight of cement Vf=1.5%

Flowability Test Results

High Strength hooked fiber Vf = 1.5%

>600mm

Flowability Test Results

Compression Testing

(High Strength hooked fiber Vf = 1.5%)

Tension Testing

(High Strength hooked fiber Vf = 1.5)

Cyclic Load

SpecimenSpecimen

Loading Brush

Loading Brush

Size of specimen: 5.5 in. x 5.5 in. x 1.4 in.

Four independent loading actuators

In-plane and out-of-plane displacements at the front panel are captured by the Krypton non-contact system whereas out-of-plane displacements at the back are measured by LVDT.

Panel Tests of HPFRCC at UIUC

Compression-CompressionQuadrant

Tension-TensionQuadrant

(Symmetry)

Loading Paths

2

f’c

1

f’c

Compression-CompressionQuadrant

Tension-TensionQuadrant

(Symmetry)

Loading Paths

2

f’c

2

f’c

1

f’c

1

f’c

0

10

20

30

40

50

60

70

0 0.005 0.01 0.015 0.02 0.025

Stress (MPa)

Str

ain

1.5% Spectra Fibers

0.3C - C

C - C

Uniaxial

Isolated HPFRCC Coupling Beam Tests at UM

HPFRCC Test Specimen

Projected Test Program Details

Specimen CB–1 Precast beam to be embedded 1” into wall with

sufficient development of beam reinforcement extended into shear wall boundary region.

Minimal shear keys provided to prevent sliding shear failure at interface

Coupling beam maximum expected moment: 2500 k-in Max expected shear: Diagonals expected to carry 25% of shear demand

11 cf

Construction of Composite Beam

Cracking Pattern and Failure Mode

SP-1 vs. SP-4 at 1.5% Drift

SP-1 SP-4

Shear Stress vs. Beam Drift Response SP-1 vs. SP-4

-10

-8

-6

-4

-2

0

2

4

6

8

10

-6 -4 -2 0 2 4 6

Sh

ea

r S

tre

ss

(MP

a)

Drift(%)

SP-1 SP-4

c) Prototype 10-story Wall Structure

a) Coupling Beam Component Test

b) Coupled Wall Specimen

NEESGridComputer Clusters

Storage Devices

Middleware

Networking

MGRID

NPACI Clusters

Storage Devices

Middleware

FEA Code

Networking

1.6 m0.9 m

1.0 m

1.0 m

Precast HPFRCC Coupling Beam

RC Wall

RC Wall

LBCB (attached to strong wall)

1.6 m

1.6 m

1.0 m

1.0 m

1.0 m

0.4 m

1.5 m 0.7 mRC Coupled Wall

Precast HPFRCC Coupling Beams

LBCBs (attached to strong wall)

RC Loading Block

RC Wall Foundation

Testing of Coupled Shear Walls at MUST-SIM Facility

Ductile HPFRCC Infill Panels for Seismic Retrofit for Steel Moment Frames

HPFRCC Infill Panels Existing Steel Frame

Nelson Stud in concrete deck

Steel Beam

PretensionedBolts

Steel Plate

Bent Steel Plate

Panel Design & Analysis

Principle Tensile Strain Contours

Nonlinear Finite Element Analysis using DIANA

Studying variations in panel shape, thickness and reinforcement layout

Hysteretic results used in larger-scale fiber element analyses

Panel Design & Analysis

Fiber Element Analysis using OpenSees

Conducting pushover and time-history analyses to evaluate capacity and demand in frames with various infills and infill arrangements

P

2P

Infill Panel

Connections

Retrofit Goals: Protect frame from brittle

fracture as per FEMA 355D

Limit yielding of frame

Experiments

Single Panel Tests @ U. Michigan

Summer ‘06

Pseudo-dynamic Testing of Infilled Frames @ NEES-Berkeley

Fall ‘08

Double Panel Tests @ U. Michigan

Winter ‘07

u2

v2 v2 u1

21

OpenSeesOpenSees

Computational substructure

Experimental substructure

Coupled Wall System: Coupled Wall System:

Mixed displacement/load controlMixed displacement/load control

HybridSimulation:

HybridSimulation:

Axial loads to be considered because moment capacity of the coupled wall is greatly affected by the axial load

u2

v2 V1 u1

2 1

Current Progress on Hybrid Simulation

EOT Components

Summer appointments in research groups at UM and Stanford (various programs)

Educational outreach to colleges/universities specializing in undergraduate education Contacts established at Lawrence Tech Univ.

(near Detroit) and Calvin College (near Grand Rapids)

Earthquake Engineering component to be added to undergrad strength of materials course or structures course

Pilot program planned at UM in Fall 2006 as part of structural analysis course

Thank you

Projected Test Program Details

Experimental substructure

Computational substructure

u1

u2

Experimental substructure

Computational substructure

Experimental substructure: Beam element Computational substructure: Rectangular element

Matlab Environment:

A two-story building with linear behavior 1940 El Centro earthquake record (PGA=0.348g)

M2=22.19 (kN sec2/m)

M1=44.38 (kN sec2/m)

Numerical Simulation of Hybrid Testing (displacement control)

Experimental substructure

Computational substructure

1

~id

)~

(~

11Bii dR

111111 )~

(~

iBiii

Ni

Ni FdRdKvCMa

)~

(~

11Bii dR

i

i

i

a

v

d

1iF

Numerical Simulation of Hybrid Testing (displacement control)

Experimental substructure

Computational substructure

u1

u2

0 10 20 30 40 50 60-0.2

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

0.2

Time(sec)

Dis

pla

ce

me

nt(

m)

Displacement of the first floor

Numerical Simulation of Hybrid Testing (displacement control)