Software and Systems Engineering Standards: Verification and Validation of Sy...
Srp 2018 00
1. Developing Fiber Reinforced Concrete
Specifications For SRP Structural and Precast
Concrete applications
Barzin Mobasher
Arizona State University
2. Problem Statement
• SRP wants better specification procedures for
implementing the benefits of FRC.
• A cost-effective specification procedure that is
based on non-proprietary mix or mixes for use
in various, cast in place, precast and shotcrete
concrete applications.
3. FRC - Background
• high strength and ductile concrete has been
made possible by advances in:
particle packing, aggregate gradation
increased quality control
Innovative fibers
Chemical admixtures low water-to-cementing
materials ratio.
• Ductility and crack width control that reduces
liquid ingress, significantly enhancing durability
5. Project Objectives
• Review existing procedures on proportioning FRC mixtures and the fiber
specific characteristics affecting the overall performance;
• Develop typical FRC mixtures with locally available materials
• Recommend Test methods and Specification methods for qualification of
mixtures for various applications
• Optimize the Structural and material design procedures based on
performance criteria in consultation with SRP.
6. Project Objectives
• Provide list of specifications and testing guidelines for:
– Mechanical: strength, ductility, impact, repair, volume changes and
crack resistance
– Durability: corrosion resistance, resistance to chloride ion ingress and
freeze and thaw, shrinkage, curling, cracking.
• Provide recommendations to, and assist SRP on the
development of specifications for use for FRC mixtures.
7. Tasks
Re-visit and update the previous report.
Criteria for fibers in structural applications
Criteria for repair of existing structures and canals
Criteria for fibers in shotcrete
Incorporating fibers in concrete mixes using a performance
based specification.
8. Opportunities in use of FRC in Structural
Applications
• The phenomenal growth of the market for fiber reinforced concrete
market is a key motivator for addressing sustainability
• Economy, labor, time, materials characteristics and performance
• ACI 544 has played a significant role in developing documents to
showcase the performance of FRC materials
• Design opportunities:
– Ductility, durability, crack width, stiffness, cracked section modulus.
– Shear
– A hybrid approach of combining reinforcement and fibers is the key to
addressing sustainability
– Minimum reinforcement requirements.
10. Seismic Design, Coupling beams, ACI-318 provisions
Eliminate a substantial amount of reinforcing bars by using a highly flowable, steel
fiber-reinforced concrete where the fibers are introduced during the concrete mixing
process.
11. Canal lining, WWF, or rebar replacement
Fiber Reinforced Concrete Mix
Photo Courtesy: Pima-Maricopa Irrigation
Project, Sacaton, Arizona
Traditional #5 rebar layout
Photo Courtesy: Rick Shelly, Pulice
Construction
13. Tunnel Lining
• Fiber-reinforced concrete can be used in tunnel lining segments.
• Macro steel fibers and macro synthetic fibers are mainly used for this type of application.
• Using fibers can reduce or even eliminate the steel rebar reinforcement which results in
faster and cheaper production.
M. Moccichino et al., 2010 world
tunnel conference, Italy
BEKAERT
14. FRC Engineering Applications
Ductility, Durability, Sustainability
The type and volume fraction of fibers affect the level of
energy absorption
increased energy absorption, fatigue life, impact/explosive
loading conditions, and seismic resistance
Pavements/slabs,Precast components, Shotcrete
15. Structural Design with FRC Materials: testing, modeling, analysis
and Design
Shotcrete applicationsElevated slabs Precast panels
Design with Strain
Softening materials
17. Analysis of Precast Wall Panels
• Assume continuous wall, pin connection at the
bottom and free at the top
• Lateral water pressure in ultimate and
serviceability limit states
19. ACI related International Committee Reports
ACI 544.5R-10 “Physical Properties and Durability of Fiber-Reinforced Concrete,”
Report, ACI Committee, p. 31, (2010).
ACI 544.6R-15 Report on Design and Construction of Steel Fiber-Reinforced
Concrete Elevated Slabs (2015)
ACI 544.7R-16 Report on Design and Construction of Fiber-Reinforced Precast
Concrete Tunnel Segments (2016)
ACI 544.8R-16: Report on Indirect Method to Obtain Stress-Strain Response of
Fiber-Reinforced Concrete (FRC), ACI Committee 544 ACI 544.8R (2016)
ACI 544.9R-17: Report on Measuring Mechanical Properties of Hardened Fiber-
Reinforced Concrete, (2017)
https://www.concrete.org/Portals/0/Files/PDF/Previews/544.9R-17_preview.pdf
ACI 544.10R-17: Report on Measuring Properties of Fresh Fiber-Reinforced
Concrete, (2018)
ACI 544-4R ACI 544.4R-18: Report on Structural Design with Fiber-Reinforced
Concrete (2018)
20.
21.
22. FRC 2014 Joint ACI-fib International Workshop
Fibre-reinforced concrete: From design to
structural applications, Montreal, Quebec
FRC 2018, Joint ACI-fib-Rilem International
Workshop, Lake Garda, Italy
Members of ACI 544 and fib TG 4.1 have been
involved in writing code-based specifications for
the design of FRC structural members.
Model code has been using Fibers for Structural
Design for several years now
fib Model Code 2010 includes specific sections
for design of FRC elements.
23. Consideration of Residual strength Effect
0 0.03 0.06 0.09 0.12 0.15
CMOD, inch
0
500
1000
1500
2000
2500
3000
Load,lbf
36 hrs - Sample 1
36 hrs - Sample 2
16 hrs - Sample 1
16 hrs - Sample 2
8 hrs - Sample 1
8 hrs - Sample 2
Three Point Bending Test Result
Mix 1
10-12 lbs/yd3 of macro fibers
24. Stress distribution for a cracked material with Strain-Softening
FRC
0 0.01 0.02 0.03 0.04 0.05
Deflection, in
0
200
400
600
800
1000
FlexuralLoad,lb
Experiment
Present Model
L-056 : 9.5 lb/yd3 FibraShield
sample 1
age: 14 days
0 400 800 1200 1600
Stress (psi)
-2
-1
0
1
2
SpecimenDepth,(in)
ARS Method, LE material
ASU Method, Elastic Softening
Stress Distribution
Softening Zone
L056-01
28. Advantages of using SFRC elevated slab: Pumping Reinforcement
– Reduction in labor force and finishing personnel
– 30% cost saving vs. traditional methods
– Shrinkage cracking control
– Bay areas larger than traditional areas
– Detailing cost reduction
31. Modeling of Failure Mechanisms
Oberseite - ULS Mittellast
S
N
West Ost
Unterseite
S
N
WestOst
Durchgezogen: bis 200 kN
gestrichelt: bis Brucklast
32. Plastic analysis approach
Distributed load on a simply supported square slab.
The work equations are derived as:
Where the resultant NR and rotation θ (from figure 9a)
are:
For the four segments with an NR acting at 1/3 of δmax :
θ θ
q
δmax
L
L/2
L/2
m
m
A A
δ
Yield Line
Square Slab
Simply Supported
int extW W
R( N ) ( M L )
2
2 2 4
R
L L qL
N q ( ) ( )
2 max
L
2
2
4 4
4 3
max max
L
qL
( ) ( ) ( M ) ( L ) ( )
2
24
ult
p
q L
M
33. Use of Yield Line Analysis and Design procedures
int extW W
2
2
P
L
M P P
4
ult
P
P L
M
34. Analysis, Design and Installation of precast water
tank panels
• Load Case1:
– Self weight + Water pressure
– Moment in short span controls
Load Case2:
– 1.4 Self weight +
1.7 Earth pressure +
1.7 Uniform pressure due to surcharge
– Moment in short span direction SM1
35. Mechanics of Fiber and Textile Reinforced
Cement Composites
• CRC press, 2011
• E-mail: barzin@asu.edu
• http://enpub.fulton.asu.edu/cement/
36. Conclusions
• New technologies and directions are clearly available in our future
progression in Construction industry.
• Use of materials science based and mechanics based approaches to
obtain better ways to characterize, model, analyze, and design.
• Better train, communicate, and follow through
– Design of Materials and Structures for novel construction.
• Address specifications, quality, and long term performance.
• Fiber Reinforced Concrete can be effectively used as a technology
enabler for our alternative energy generation, use and infrastructure
development
39. Modelling procedures
• Tension model
• Compression model
• Bond (interface) model
• Stress/strain distribution
• Moment-curvature relationship
• Normalized parameters
• Incorporations of equilibrium equations
• Moment and curvature distributions throughout the volume
• Integration, application of boundary conditions
• Data reduction and solutions for stress, strain, load, deflection distributions
40. Mix Designs
• Designing the fiber Content, type,
applications, and reinforcement
strategy with plain or hybrid cases.
– Local materials and combinations
• Rheological properties, compaction
Particle packing
methods Rheology experiments
41. Testing of FRC concretes
• Mixing and placing of UHPC
• Strength and modulus development
• Toughness/Ductility
0.0000 0.0002 0.0004 0.0006 0.0003 0.0008 0.0013 0.00175
