This document discusses the design of precast reinforced concrete structures including precast panels, cast in place water tanks, and fiber reinforced concrete slabs. It outlines the design, analysis, testing, and modeling of these structures. Precast panels are made of concrete and rebar on site and assembled using bolts and epoxy. Finite element analysis is used to model water tanks under lateral loads. Round panel and full-scale fiber reinforced concrete slab tests are conducted and modeled to evaluate post-crack tensile capacity.

1. Design of Precast Reinforced Concrete Structures
Chote Soranakom
Masoud Yekani Fard
Prof. Barzin Mobasher

2. FULTON
s c h o o l o f e n g i n e e r i n g
Outline
 Precast panels
– Ultimate and serviceability design
– SRP Design chart
 Cast in place water tanks
– Finite element analysis
– ASU design methodology
 Fiber reinforced concrete slab
– Round panel tests
– Full scale testing of flat slab
– Finite element simulation of flat slab

3. FULTON
s c h o o l o f e n g i n e e r i n g
Pre-cast panels
 Panels are made of plain concrete and steel rebar to be
installed on site

4. FULTON
s c h o o l o f e n g i n e e r i n g
Installation of pre-cast water tank
 Panels are
assembled on
site
 The wall joints
are connected
using bolts and
epoxy
 The base slab is
connected to the
periphery walls by
friction through
slots

5. FULTON
s c h o o l o f e n g i n e e r i n g
Analysis of Wall Panels
 Assume continuous wall,
pin connection at the
bottom and free at the
top
 Lateral water pressure in
ultimate and
serviceability limit states

6. FULTON
s c h o o l o f e n g i n e e r i n g
Critical Internal Forces
 Critical moment,
shear, and axial
forces
– Horizontal
– Vertical
 Design thickness
and reinforcement
for both
– Ultimate
– Serviceability

7. FULTON
s c h o o l o f e n g i n e e r i n g
SRP Design Chart
 The thickness
and reinforcing
mesh for
panels of tanks
with different
dimensions
 Design using
ACI ultimate
limit state
0 10 20 30
Maximum Clear Span (ft)
0
5
10
15
20
EffectiveDepth(ft)(finighgradetofloor)
Over strength
Needs more
reinforcement
Reinforcement and
thickness is okay
3
2
1 4
5
1
4
3
2
5
6" wall with # 4@ 12"
6" wall with # 4@ 6"
8" wall with # 5@ 12"
8" wall with # 5@ 6"
Analysis required

8. FULTON
s c h o o l o f e n g i n e e r i n g
Cast in Place Water Tank
 For small dimension, the
cast in place water tank
is usually used.

9. FULTON
s c h o o l o f e n g i n e e r i n g
Finite Element Analysis
 Lateral loading
– Water
– Earth pressure
– Surcharge
 Finite element model
– Shell elements

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s c h o o l o f e n g i n e e r i n g
Analysis Results
 Load Case1:
– 1.4 Self weight +
1.4 Water pressure
– Moment in short span
direction SM1
 Load Case2:
– 1.4 Self weight +
1.7 Earth pressure +
1.7 Uniform pressure due to surcharge
– Moment in short span direction SM1

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s c h o o l o f e n g i n e e r i n g
Material Models
 (a) rectangular cross
section
 (b) tension model
 (c) compression model
 (d) steel model

12. FULTON
s c h o o l o f e n g i n e e r i n g
Simplified Design Equation
0 1 2 3
Normalized Ultimate Moment, M'u
0
1
2
3
NormalizedMomentatInfinity,M'
0
1
2
3
M
'
=
3/(+)
3
'M

  

21
6
cr crM bd
0.90 'u crM M M 
where
For plain strain softening FRC only

13. FULTON
s c h o o l o f e n g i n e e r i n g
Concrete Flat Slab
 Flat slab was constructed by only fiber reinforced
concrete in France

14. FULTON
s c h o o l o f e n g i n e e r i n g
Round Panel Test
 Fiber reinforced concrete round panel tests were conducted to
evaluate post crack tensile strength capacity
(a) (b)

15. FULTON
s c h o o l o f e n g i n e e r i n g
Construction and Field Testing
 Cast in place SFRC
 Use minimum reinforcement along the column lines to
prevent progressive collapse

16. FULTON
s c h o o l o f e n g i n e e r i n g
Inverse Analysis of Round Panel Tests
 Tensile stress crack width were obtained by inverse
analysis, using finite element method
– Mix Vf=80 kg/m3
– Mix Vf=100 kg/m3
0 10 20 30
Deflection (mm)
0
50
100
150
200
Load(kN)
Experiment Vf 100 kg/m3
Simulation Vf 100 kg/m3
Experiment Vf 80 kg/m3
Simulation Vf80kg/m3
0 0.5 1 1.5 2
Crack Width (mm)
0
0.5
1
1.5
2
2.5
TensileStress(MPa)
Vf 100 kg/m3
Vf 80 kg/m3
E=20,000 MPa, =0.15
(Vf=80kg/m3)
E=24,000 MPa, =0.15
(Vf=100kg/m3)
(a) (b)

17. FULTON
s c h o o l o f e n g i n e e r i n g
Full Scale Testing of Concrete Flat Slab
 Point load was applied at the center panel
 Deflections were measured and crack patterns were
monitored

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s c h o o l o f e n g i n e e r i n g
Finite Element Model
 For efficiency reason, model the slab for only the upper
quarter

19. FULTON
s c h o o l o f e n g i n e e r i n g
Crack Predictions
Oberseite - ULS Mittellast
S
N
West Ost
Unterseite
S
N
WestOst
Durchgezogen: bis 200 kN
gestrichelt: bis Brucklast

20. FULTON
s c h o o l o f e n g i n e e r i n g
Septic Tanks

21. FULTON
s c h o o l o f e n g i n e e r i n g

22. FULTON
s c h o o l o f e n g i n e e r i n g
Full Capacity Testing

23. FULTON
s c h o o l o f e n g i n e e r i n g
Conclusions
 Fiber reinforced concrete can be used in
precast and cast in place structural
element
 ASU has developed the model and
design methodology for structural
members

24. FULTON
s c h o o l o f e n g i n e e r i n g
References
 Soranakom, C., and Mobasher, B., “Closed-Form
Solutions for Flexural Response of Fiber-Reinforced
Concrete Beams,” Journal of Engineering Mechanics,
Vol. 133, No. 8, August, 2007, pp. 933-941.
 Soranakom, C., and Mobasher, B., “Analytical Modeling
of Fiber Reinforced Concrete with and without
Conventional Steel Rebar” Journal of Structural
Engineering, (in press)
 Soranakom, C., and Mobasher, B., Destrée, X..,
“Numerical Simulation of FRC Round Panel Tests and
Full-Scale Elevated Slabs,” ACI SP-248-3, Deflection
and Stiffness Issues in FRC and Thin Structural
Elements, October 2007, pp. 31-40.
 Bernard E.S., “Behaviour of Round Steel Fibre
Reinforced Concrete Panels under Point Loads,”
Materials and Structures, Vol.33 Apr 2000, pp.181-188.
 ACI Committee 318, Building Code Requirements for
Structural Concrete (ACI 318-02) and Commentary
(ACI 318R-02), American Concrete Institute,
Formington Hills MI,various editions