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Transcript of Tesi angela saviotti
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”PRECAST CONCRETE BEAM-COLUMN DUCTILE CONNECTIONS”
Advisor:
Prof. Ing. Franco Bontempi
Co-advisor:
Ing. Pierluigi Olmati
Candidate:
Angela Saviotti
Treated models
2D MODEL:
-Model “A” with mortar stratum for beam-column connection;
-Model “B” without mortar stratum for beam-column connection.
“Finite element analysis of innovative solutions of precast concrete beam-column
ductile connections”
2D “A” 2D “B”
Faculty of Civil and Industrial EngineeringDepartment of Structural and Geotechnical Engineering 2/25
•3D MODEL:
-Model “A” with mortar stratum for beam-column connection;
-Model “B” without mortar stratum for beam-column connection.
3D “A” 3D “B”
“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
3/25
-Yielding of the steel.
Faculty of Civil and Industrial EngineeringDepartment of Structural and Geotechnical Engineering
CONCRETE – Total Strain Crack Model
Tensile Behavior Compressive Behavior
STEEL – Von Mises
Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
Beam
L=3770 mm
Column
H=4700 mm
STRUCTURE
4/25Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering
BOUNDARY CONDITIONS AND LOADS
FIRST LOAD CONDITION
SEISMIC SITUATION
2D
Beam-Column
joint failure after
earthquake -
http://strutturisti.
wordpress.com/
Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
5/25
SECOND LOAD CONDITION
ACCIDENTAL SITUATION
Faculty of Civil and Industrial EngineeringDepartment of Structural and Geotechnical Engineering
The Bombing of the Federal
Building in Oklahoma City -
http://911research.wtc7.net/ind
ex.html
Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
MODEL “A” MODEL “B”
6/25Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering
MODEL 2DMESH
Four-node quadrilateral plane
Concrete, Mortar, Rubber and Steel Plates
Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
Beam and Column:
Concrete C40/50
Rubber padConnection
Stratum:
Mortar
Steel Plates
MODEL “A”
MODEL “B”
7/25
Four-node quadrilateral plane
stress elements (Q8MEM)
Three-node triangle plane stress
elements (T6MEM)
Faculty of Civil and Industrial EngineeringDepartment of Structural and Geotechnical Engineering
MODEL “B”
Zoom of Beam-Column jointReinforcing Steel
Two-node straight truss
elements (L2 TRU)
Linear Elasticity Ideal Plasticity Linear Elasticity Ideal Linear Elasticity
Tension Softening
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
STEEL CONCRETE
Compressive Behavior Tensile Behavior
NON LINEAR ANALYSIS
FIRST LOAD CONDITION : Applied Horizontal Force at the top of the column 2D
Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
8/25Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering
Linear Elasticity Ideal Plasticity Linear Elasticity Ideal Linear Elasticity
Tension Softening
curve based on
fracture energy
STEEL CONCRETE
Compressive Behavior Tensile Behavior
FIRST LOAD CONDITION : Applied Horizontal Force at the top of the column
NON LINEAR ANALYSIS
2D
Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
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
9/25Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering
NON LINEAR ANALYSIS – CYCLIC ANALYSIS
MODEL “A”
SECOND LOAD CONDITION : Imposed vertical displacement at the top of the column
Deformed
configuration developed
by the structure at STEP
n. 25 imposed maximum
displacement δ=80 mm.
2D
Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
10/25Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering
MODEL “A”
Step 25, imposed
displacement δ=80
mm
Step 50, imposed
displacement δ=0
mm
Step 80, imposed
displacement δ= - 80 mm
Step 110, imposed
displacement δ=0 mm
Step 25
Step 50Step 80
Step 110
2D
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 – CYCLIC ANALYSIS
11/25Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering
Step 25 σmax=450 .0 N/mmq Step 50 σmin = - 450 .0 N/mmq
Step 80 σmin= - 450 .0 N/mmq Step 110 σmin= - 203.25 N/mmq
STRESS on reinforcing steelCRACKING STATUS
Step 25
Step 50 Step 80
Step 1
Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
12/25Faculty of Civil and Industrial EngineeringDepartment of Structural and Geotechnical Engineering
MODEL 3DMESH
Four-node, three-side iso-
parametric solid pyramid
elements (TE12L)
Concrete, Mortar, Rubber and Steel Plates
158634 solid elements
9106 bar elements
31639 nodes Two-node straight truss
Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
13/25Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering
31639 nodes
Total of around 142941 degree of
freedom
Two-node straight truss
elements (L2 TRU)
Two-node, two-
dimensional class-II
beam element (L7BEN)
MODEL “A”
Displacements
MODEL “B”
mm mm
LINEAR ANALYSIS
FIRST LOAD CONDITION: Applied Horizontal Force of 600 kN at the top of the column
3D
Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
14/25Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering
MODEL “A”
Stress on reinforcing steel
MODEL “B”
LINEAR ANALYSIS
FIRST LOAD CONDITION: Applied Horizontal Force at the top of the column
Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
c
15/25Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering
NON LINEAR ANALYSIS
FIRST LOAD CONDITION : Applied Horizontal Force at the top of the column 3D
Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
16/25Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering
FIRST LOAD CONDITION : Applied Horizontal Force at the top of the column
NON LINEAR ANALYSIS
MODEL “A”MODEL “B”
mmmm
3D
Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
17/25
Deformed configuration developed by the structure at
STEP 20 – Fmax= 390.2 kN, δmax=88.6 mm.
Deformed configuration developed by the structure at
STEP 15 - Fmax= 269.83 kN, δmax=87.27 mm
Faculty of Civil and Industrial EngineeringDepartment of Structural and Geotechnical Engineering
NON LINEAR ANALYSIS: Stress on Reinforcing Steel
MODEL “A” MODEL “B”
STEP 5 Fmax= 128 kN,
δmax=5.17 mm
σmax=108.21 N/mmq
FIRST LOAD CONDITION : Applied Horizontal Force at the top of the column
STEP 5 Fmax= 128.7 kN,
δmax=6.97 mm
σmax=233.0 N/mmq
Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
3D
18/25Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering
STEP 10 Fmax= 207 kN,
δmax=12.75 mm –
σmax= 206.66 N/mmq
STEP 20 Fmax= 390 kN,
δmax=88.56 mm
σmax=450.0 N/mmq
STEP 15 Fmax=270 kN,
δmax=87.27 mm
σmax=450.0 N/mmq
STEP 10 Fmax= 205 kN,
δmax=16.9 mm
σmax=365.0 N/mmq
NON LINEAR ANALYSIS: Stress on Reinforcing Steel
MODEL “A” MODEL “B”
STEP 5 Fmax= 128 kN,
δmax=5.17 mm
σmax=108.21 N/mmq
FIRST LOAD CONDITION : Applied Horizontal Force at the top of the column
STEP 5 Fmax= 128.7 kN,
δmax=6.97 mm
σmax=233.0 N/mmq
3D
Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
19/25Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering
STEP 10 Fmax= 207 kN,
δmax=12.75 mm –
σmax= 206.66 N/mmq
STEP 20 Fmax= 390 kN,
δmax=88.56 mm
σmax=450.0 N/mmq
STEP 15 Fmax=270 kN,
δmax=87.27 mm
σmax=450.0 N/mmq
STEP 10 Fmax= 205 kN,
δmax=16.9 mm
σmax=365.0 N/mmq
FIRST LOAD CONDITION: Applied Horizontal Force at the top of the column
NON LINEAR ANALYSIS: Cracking Status
MODEL “A” MODEL “B”
STEP 5 Fmax= 128 kN,
δmax=5.17 mm
STEP 5 Fmax= 128.7 kN,
δmax=6.97 mm
3D
Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
20/25Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering
STEP 10 Fmax= 207 kN,
δmax=12.75 mm
STEP 20 Fmax= 390 kN,
δmax=88.56 mm
STEP 10 Fmax= 205 kN,
δmax=16.9 mm
STEP 15 Fmax=270 kN,
δmax=87.27 mm
NON LINEAR ANALYSISMODEL “A” MODEL “B”
Deformed
configuration developed
by the structure at LAST
STEP imposed
displacement δ=120 mm.
Deformed
configuration developed by
the structure at LAST STEP
imposed displacement
δmax=150 mm
SECOND LOAD CONDITION : Imposed vertical displacement at the top of the column 3D
Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
21/25Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering
Force-Displacement graph: Model “A” Vs. Model “B” Stress–Strain graph of beam-column ductile connection Model “A” Vs
Model “B”
NON LINEAR ANALYSIS: Stress on Reinforcing Steel
MODEL “A” MODEL “B”
SECOND LOAD CONDITION : Imposed vertical displacement at the top of the column
STEP 1 Fmax= 123.6 kN,
δmax=10 mm
σmax=268.1 N/mmq
STEP 1 Fmax= 143.9 kN,
δmax=10 mm
σmax=196.41 N/mmq
STEP 5 Fmax= 232.5kN,
δmax=50 mm
σmax=450.0 N/mmq
STEP 5 Fmax= 139.4 kN,
δmax=50 mm
σmax=348.3N/mmq
3D
Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
22/25Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering
STEP 12 Fmax= 223.13
kN, δmax= 120 mm
σmax=450.0 N/mmq
σmax=348.3N/mmq
STEP 12 Fmax= 139.95
kN, δmax=120 mm
σmin=-450.0 N/mmq
NON LINEAR ANALYSIS: Crack Strain
MODEL “A” MODEL “B”
SECOND LOAD CONDITION : Imposed vertical displacement at the top of the column
STEP 1 Fmax= 143.9 kN,
δmax=10 mm
εknn=0.00242 %
STEP 1 Fmax= 123.6 kN,
δmax=10 mm
εknn=0.00703 %
3D
Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
23/25Faculty of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering
STEP 5 Fmax= 232.5kN,
δmax=50 mm
εknn=0.0359 %
STEP 12 Fmax= 223.13
kN, δmax= 120 mm
εknn=0.224%
STEP 5 Fmax= 139.4 kN,
δmax=50 mm
εknn=0.0548 %
STEP 12 Fmax= 139.95
kN, δmax=120 mm
εknn=0.132 %
• 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
Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
24/25
• 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 EngineeringDepartment of Structural and Geotechnical Engineering
2D
Angela Saviotti - Finite element analysis of innovative solutions of precast concrete beam-column ductile connections
25/25Faculty of Civil and Industrial EngineeringDepartment of Structural and Geotechnical Engineering
3D