This document describes a finite element analysis of innovative precast concrete beam-column connections. 2D and 3D models were created to analyze connections with and without a mortar stratum. Nonlinear analyses subjected the connections to seismic and accidental loading. The analysis found that connections with a mortar stratum developed the full capacity of reinforcing steel without concrete failure and better reproduced cracking behavior. The mortar stratum was determined to improve structural continuity.
“A REVIEW STUDY ON PUSHOVER ANALYSIS OF SYMMETRIC BUILDING ON FLAT & SLOPING ...
Tesi angela saviotti
1. a. a. 2011-2012
Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering
“FINITE ELEMENT ANALYSIS OF INNOVATIVE SOLUTIONS OF
PRECAST CONCRETE BEAM-COLUMN DUCTILE CONNECTIONS”
Advisor: Candidate:
Prof. Ing. Franco Bontempi Angela Saviotti
Co-advisor:
Ing. Pierluigi Olmati
2. “Finite element analysis of innovative solutions of precast concrete beam-column
ductile connections”
Treated models
2D MODEL:
-Model “A” with mortar stratum for beam-column connection;
-Model “B” without mortar stratum for beam-column connection.
2D “A” 2D “B”
•3D MODEL:
-Model “A” with mortar stratum for beam-column connection;
-Model “B” without mortar stratum for beam-column connection.
3D “A” 3D “B”
Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering 2/25
3. “Finite element analysis of innovative solutions of precast concrete beam-column
ductile connections”
•FEM analytical program: DIANA V. 9.3
•Geometry and Mesh of the structure, to assign boundary
conditions and loads: Midas FX+ for DIANA
•Non-linear mechanisms :
-Cracking of the concrete
-Yielding of the steel.
CONCRETE – Total Strain Crack Model STEEL – Von Mises
Tensile Behavior Compressive Behavior
Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering 3/25
4. Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
STRUCTURE
Column
H=4700 mm
Beam
L=3770 mm
Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering 4/25
5. Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
BOUNDARY CONDITIONS AND LOADS 2D
Beam-Column
FIRST LOAD CONDITION joint failure after
SEISMIC SITUATION earthquake -
http://strutturisti.
wordpress.com/
SECOND LOAD CONDITION
ACCIDENTAL SITUATION
The Bombing of the Federal
Building in Oklahoma City -
http://911research.wtc7.net/ind
ex.html
Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering 5/25
6. Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
MODEL “A” MODEL “B”
Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering 6/25
7. Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
MODEL 2D
MESH
Steel Plates Beam and Column:
Concrete, Mortar, Rubber and Steel Plates Concrete C40/50
MODEL “A”
Rubber pad Connection
Stratum:
Mortar
MODEL “B” Four-node quadrilateral plane
stress elements (Q8MEM)
Reinforcing Steel Zoom of Beam-Column joint
Two-node straight truss
elements (L2 TRU) Three-node triangle plane stress
elements (T6MEM)
Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering 7/25
8. Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
FIRST LOAD CONDITION : Applied Horizontal Force at the top of the column 2D
NON LINEAR ANALYSIS
STEEL CONCRETE
Compressive Behavior Tensile Behavior
Tension Softening
Linear Elasticity Ideal Plasticity Linear Elasticity Ideal Linear Elasticity curve based on
fracture energy
A1 X X X
B1 X X X
A2.1 X X X
B2.1 X X X
A3.1 X X X
B3.1 X X X
A4.4 X X X
B4.4 X X X
Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering 8/25
9. Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
FIRST LOAD CONDITION : Applied Horizontal Force at the top of the column 2D
NON LINEAR ANALYSIS
STEEL CONCRETE
Compressive Behavior Tensile Behavior
Tension Softening
Linear Elasticity Ideal Plasticity Linear Elasticity Ideal Linear Elasticity curve based on
fracture energy
A1 X X X
B1 X X X
A2.1 X X X
B2.1 X X X
A3.1 X X X
B3.1 X X X
A4.4 X X X
B4.4 X X X
Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering 9/25
10. Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
SECOND LOAD CONDITION : Imposed vertical displacement at the top of the column 2D
NON LINEAR ANALYSIS – CYCLIC ANALYSIS
MODEL “A”
Deformed
configuration developed
by the structure at STEP
n. 25 imposed maximum
displacement δ=80 mm.
Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering 10/25
11. Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
SECOND LOAD CONDITION : Imposed vertical displacement at the top of the column 2D
NON LINEAR ANALYSIS – CYCLIC ANALYSIS
MODEL “A”
Step 25
Step 50, imposed Step 110
Step 25, imposed
displacement δ=80 displacement δ=0
mm mm
Step 80 Step 50
Step 80, imposed Step 110, imposed
displacement δ= - 80 mm displacement δ=0 mm
STRESS on reinforcing steel
CRACKING STATUS
Step 25
Step 1
Step 25 σmax=450 .0 N/mmq Step 50 σmin = - 450 .0 N/mmq
Step 50 Step 80
Step 80 σmin= - 450 .0 N/mmq Step 110 σmin= - 203.25 N/mmq
Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering 11/25
12. Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering
12/25
13. Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
MODEL 3D
MESH
Concrete, Mortar, Rubber and Steel Plates Four-node, three-side iso-
parametric solid pyramid
elements (TE12L)
158634 solid elements
9106 bar elements
31639 nodes
Total of around 142941 degree of Two-node straight truss
freedom elements (L2 TRU)
Two-node, two-
dimensional class-II
beam element (L7BEN)
Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering 13/25
14. Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
FIRST LOAD CONDITION: Applied Horizontal Force of 600 kN at the top of the column
3D
LINEAR ANALYSIS
Displacements
MODEL “A” MODEL “B”
mm mm
Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering 14/25
15. Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
FIRST LOAD c
CONDITION: Applied Horizontal Force at the top of the column
LINEAR ANALYSIS
Stress on reinforcing steel
MODEL “A” MODEL “B”
Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering 15/25
16. Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
3D
FIRST LOAD CONDITION : Applied Horizontal Force at the top of the column
NON LINEAR ANALYSIS
Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering 16/25
17. Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
3D
FIRST LOAD CONDITION : Applied Horizontal Force at the top of the column
NON LINEAR ANALYSIS
MODEL “A” MODEL “B”
mm
mm
Deformed configuration developed by the structure at Deformed configuration developed by the structure at
STEP 20 – Fmax= 390.2 kN, δmax=88.6 mm. STEP 15 - Fmax= 269.83 kN, δmax=87.27 mm
Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering 17/25
18. Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
FIRST LOAD CONDITION : Applied Horizontal Force at the top of the column 3D
NON LINEAR ANALYSIS: Stress on Reinforcing Steel
MODEL “A” MODEL “B”
STEP 5 Fmax= 128 kN, STEP 5 Fmax= 128.7 kN,
δmax=5.17 mm δmax=6.97 mm
σmax=108.21 N/mmq σmax=233.0 N/mmq
STEP 10 Fmax= 205 kN,
STEP 10 Fmax= 207 kN, δmax=16.9 mm
δmax=12.75 mm – σmax=365.0 N/mmq
σmax= 206.66 N/mmq
STEP 15 Fmax=270 kN,
STEP 20 Fmax= 390 kN, δmax=87.27 mm
δmax=88.56 mm σmax=450.0 N/mmq
σmax=450.0 N/mmq
Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering 18/25
19. Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
FIRST LOAD CONDITION : Applied Horizontal Force at the top of the column 3D
NON LINEAR ANALYSIS: Stress on Reinforcing Steel
MODEL “A” MODEL “B”
STEP 5 Fmax= 128 kN, STEP 5 Fmax= 128.7 kN,
δmax=5.17 mm δmax=6.97 mm
σmax=108.21 N/mmq σmax=233.0 N/mmq
STEP 10 Fmax= 205 kN,
STEP 10 Fmax= 207 kN, δmax=16.9 mm
δmax=12.75 mm – σmax=365.0 N/mmq
σmax= 206.66 N/mmq
STEP 15 Fmax=270 kN,
STEP 20 Fmax= 390 kN, δmax=87.27 mm
δmax=88.56 mm σmax=450.0 N/mmq
σmax=450.0 N/mmq
Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering 19/25
20. Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
FIRST LOAD CONDITION: Applied Horizontal Force at the top of the column 3D
NON LINEAR ANALYSIS: Cracking Status
MODEL “A” MODEL “B”
STEP 5 Fmax= 128 kN, STEP 5 Fmax= 128.7 kN,
δmax=5.17 mm δmax=6.97 mm
STEP 10 Fmax= 205 kN,
STEP 10 Fmax= 207 kN, δmax=16.9 mm
δmax=12.75 mm
STEP 15 Fmax=270 kN,
STEP 20 Fmax= 390 kN, δmax=87.27 mm
δmax=88.56 mm
Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering 20/25
21. Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
SECOND LOAD CONDITION : Imposed vertical displacement at the top of the column
NON LINEAR ANALYSIS 3D
MODEL “A” MODEL “B”
Deformed Deformed
configuration developed configuration developed by
by the structure at LAST the structure at LAST STEP
STEP imposed imposed displacement
displacement δ=120 mm. δmax=150 mm
Stress–Strain graph of beam-column ductile connection Model “A” Vs
Force-Displacement graph: Model “A” Vs. Model “B” Model “B”
Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering 21/25
22. Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
SECOND LOAD CONDITION : Imposed vertical displacement at the top of the column
NON LINEAR ANALYSIS: Stress on Reinforcing Steel 3D
MODEL “A” MODEL “B”
STEP 1 Fmax= 143.9 kN,
δmax=10 mm
σmax=196.41 N/mmq
STEP 1 Fmax= 123.6 kN,
δmax=10 mm
σmax=268.1 N/mmq
STEP 5 Fmax= 232.5kN,
δmax=50 mm STEP 5 Fmax= 139.4 kN,
σmax=450.0 N/mmq δmax=50 mm
σmax=348.3N/mmq
STEP 12 Fmax= 223.13 STEP 12 Fmax= 139.95
kN, δmax= 120 mm kN, δmax=120 mm
σmax=450.0 N/mmq σmin=-450.0 N/mmq
Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering 22/25
23. Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
SECOND LOAD CONDITION : Imposed vertical displacement at the top of the column
3D
NON LINEAR ANALYSIS: Crack Strain
MODEL “A” MODEL “B”
STEP 1 Fmax= 143.9 kN, STEP 1 Fmax= 123.6 kN,
δmax=10 mm δmax=10 mm
εknn=0.00242 % εknn=0.00703 %
STEP 5 Fmax= 232.5kN, STEP 5 Fmax= 139.4 kN,
δmax=50 mm δmax=50 mm
εknn=0.0359 % εknn=0.0548 %
STEP 12 Fmax= 223.13 STEP 12 Fmax= 139.95
kN, δmax= 120 mm kN, δmax=120 mm
εknn=0.224% εknn=0.132 %
Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering 23/25
24. Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
• Structural continuity is an important problem.
•DIANA software, modeling the nonlinear behavior of concrete and mortar using total
strain crack model. The reinforcing steel is modeled by a bilinear plasticity model
• The full load capacity of the bars is developed without the failure of the concrete and
the mortar
• The progress of the cracking of the concrete is well reproduced.
• The similarity between the results obtained with two different finite
element programs, the previously mentioned DIANA and ASTER.
• The role of the mortar stratum is weighted
• The introduction of the connectors inside the mass of concrete.
Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering
24/25
25. Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
2D
3D
Faculty of Civil and Industrial Engineering 25/25
Department of Structural and Geotechnical Engineering