principal investigators: james wight, univ. of michigan sarah billington, univ. of stanford
DESCRIPTION
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 Michigan Sarah Billington, Univ. of Stanford Sherif El-Tawil, Univ. of Michigan - PowerPoint PPT PresentationTRANSCRIPT
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
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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)