instrumented moment frame steel buildings models erol kalkan, phd california geological survey...
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Instrumented Moment Frame Steel Buildings Models
Erol Kalkan, PhDCalifornia Geological Survey
PEER-GMSM First Work Shop, Berkeley Oct-27 2006PEER-GMSM First Work Shop, Berkeley Oct-27 2006
PEER GMSM 2
Moment Frame Existing Steel Buildings
Analytical Model in Two-DimensionAnalytical Model in Two-Dimension 6-Story Building [Burbank, CA]6-Story Building [Burbank, CA] 13-Story Building [Los Angeles, CA]13-Story Building [Los Angeles, CA]
Analytical Model in Three-DimensionAnalytical Model in Three-Dimension 19-Story Building [Los Angeles, CA]19-Story Building [Los Angeles, CA]
PEER GMSM 3
6-story Instrumented Moment Frame Steel Building at Burbank, CA
Moment resisting steel frames on perimeter walls.
Designed in 1976 as per the 1973 UBC requirements
PEER GMSM 4
Structural Details
The structural system is essentially symmetrical. Moment continuity of each of the perimeter frames is
interrupted at the ends where a simple shear connection is used to connect to the weak column axis.
4
7
6
5
3
2
1
BA
6@6.
1 m
DC E GF
[email protected] m 6@ 6.1m
5@4m
5.3m
3rdFloor
2ndFloor
1st Floor
4th Floor
5th Floor
Roof
W14
x176
W14
x90
W14
x132
W24x68
W24x84
W24x68
W24x68
W27x102
W30x116
A C E F GDB
Moment resisting connection
Moment resisting connectionSimple hinge connection
PEER GMSM 5
Analytical Modeling in OpenSEES
One half of the total building mass was applied to the frame distributed proportionally to the floor nodes.
The simulation of special features such as local connection fracture did not accounted for; consequently, the modeling of the members and connections was based on the assumption of stable hysteresis derived from a bilinear stress-strain model with 3 percent strain hardening.
The columns were assumed to be fixed at the base level.
A force-based nonlinear beam-column element that utilizes a layered ‘fiber’ section is utilized to model all components.
Centerline dimensions were used in the element modeling.
PEER GMSM 6
Recorded Earthquake Data from 6-Story Building
Earthquake1994 Northridge 6.7 22 0.35 0.49
1992 Bigbear 6.5 137 0.04 0.111992 Landers 7.3 172 0.05 0.22
1991 Sierra Madre 5.8 30 0.11 0.161987 Whittier 6.1 26 0.22 0.30
Magnitude (Mw)
Epicentral Distance (km)
PGA Base Level (g)
PGA Roof Level (g)
The building performed well in all these earthquakes with no visible signs of damage. Recorded data indicates an essentially elastic response in each case.
-12
0
12
0 10 20 30 40 50 60Time (sec)
Dis
p. (
cm
)
RecordedSimulated
6-Story Bld.Roof
PEER GMSM 7
Dynamic Characteristics of 6-Story Building
6-Story Building Mode-1 Mode-2 Mode-3Modal Periods (sec), Tn 1.39 0.51 0.31
Modal Participation Factors, Gn 2.58 0.96 0.46Mass Participation Factors, an 0.85 0.12 0.03
Elastic Modes
0
1
2
3
4
5
6
0.00 0.02 0.04 0.06
IDR
Sto
ry L
evel
0
1
2
3
4
5
6
0.00 0.01 0.02 0.03 0.04
IDR
Sto
ry L
evel
0
1
2
3
4
5
6
0 2 4
Story Ductility
Sto
ry L
evel
0
1
2
3
4
5
6
0 2 4 6
Story Ductility
Sto
ry L
evel
Dominant Higher ModeDominant First Mode
PEER GMSM 8
13-story Instrumented Moment Frame Steel Building at Los Angeles, CA
Moment resisting steel frames on perimeter walls. Located in South San Fernando Valley. It was built in 1975 on a design based on the 1973 UBC code designed in 1976 as per the 1973 UBC requirements
PEER GMSM 9
Structural Details
The exterior frames of the building are the moment resisting frames and interior frames are for load bearing.
The foundation consists of piles, pile caps and grade beams. The corner columns of outer frames are composed of box sections.
[email protected] = 48.8 m
5
E
F
G
C
D
B
4
5@9.
76 =
48.
8 m
86 7 9
Moment resisting connection
(a) Plan view of perimeter frames
(b) Elevation
W33x118
W27x84
W33x141
W33x130
W33x130
W33x152
W33x152
W33x152
W33x141
W33x118
W36x230
W33x152
W33x152
W33x194
W14
x314
W14
x426
W14
x500
W14
x398
W14
x246
W14
x287
W14
x167
6th Floor
5th Floor
1st Floor
2nd Floor
3rd Floor
Plaza Level
4th Floor
12th Floor
Roof
9th Floor
10th Floor
11th Floor
7th Floor
8th Floor
12@
4.01
3 =
48.
2 m
4.88
4.42
[email protected] = 48.8 m
Moment resisting connectionSimple hinge connection
PEER GMSM 10
Analytical Modeling in OpenSEES
One half of the total building mass was applied to the frame distributed proportionally to the floor nodes.
The simulation of special features such as local connection fracture did not accounted for; consequently, the modeling of the members and connections was based on the assumption of stable hysteresis derived from a bilinear stress-strain model with 2 percent strain hardening.
The columns were assumed to be fixed at the base level.
Raleigh damping of 5 percent for the first and third vibration modes was utilized.
A force-based nonlinear beam-column element that utilizes a layered ‘fiber’ section is utilized to model all components.
Centerline dimensions were used in the element modeling.
PEER GMSM 11
Recorded Earthquake Data from 13-Story Building
Approximately 12% of the connections on the west perimeter of the North-South frame fractured during the Northridge earthquake.
Earthquake1994 Northridge 6.7 32 0.18 0.37
1991 Sierra Madre 5.8 33 0.17 0.18
Magnitude (Mw)
Epicentral Distance (km)
PGA Base Level (g)
PGA Roof Level (g)
-40
0
40
0 10 20 30
Dis
p. (
cm)
6th Floor -40
0
40
0 5 10 15 20 25 30Time (sec)
Dis
p. (
cm
) 13-Story Bld.Roof
13-Story Building Mode-1 Mode-2 Mode-3Modal Periods (sec), Tn 3.03 1.08 0.65
Modal Participation Factors, Gn 5.57 2.13 1.29Mass Participation Factors, an 0.77 0.11 0.04
Elastic Modes
PEER GMSM 12
19-story Instrumented Moment Frame Steel Building at Los Angeles, CA The building was design in 1967. Has 19 stories above ground and 4 parking levels below ground. Instrumented in 1992 with 15 accelerometers on 5 levels in the building.
Structure has 4 ductile frame along E-W and 5 X-braced frame in N-S direction.
PEER GMSM 13
Structural Details
Moment resisting steel frames in the longitudinal and X-braced steel frames in the transverse direction.
The diagonal members of the cross frames are composed of built-up steel sections of two or four back-to-back angles.
Pin connections fasten the diagonal members of the cross frames to the columns. The foundation consists of 72 ft (21.9 m) long, driven, steel I-beam piles.
PEER GMSM 14
Analytical Modeling in OpenSEES
Rigid diaphragm was assumed. Centerline dimensions were used in the element
modeling. Mass was distributed proportionally to the floor
nodes. The modeling of the members and connections
was based on the assumption of stable hysteresis derived from a bilinear stress-strain model with 3 percent strain hardening.
The columns were assumed to be fixed at the base level.
Raleigh damping of 3 percent for the first and third vibration modes was utilized.
3D Model was created in OpenSEES including 19+4 stories. Braces were modeled as truss elements. A force-based nonlinear beam-column element that utilizes a layered
‘fiber’ section was utilized to model all beam and columns.
PEER GMSM 15
Recorded Earthquake Data from 19-Story Building
Earthquake1994 Northridge 6.7 20 0.32 0.65
Magnitude (Mw)
Epicentral Distance (km)
PGA Base Level (g)
PGA Roof Level (g)
19-Story Building Mode-1 Mode-2 Mode-3Modal Periods (sec), Tn 3.68 3.38 3.08
Torsional Longitudional Transverse
Elastic Modes
After Northridge earthquake, no structural damage was reported. A more accurate match of the recorded response was obtained with both lateral components of the earthquake applied simultaneously.
0 5 10 15 20 25 30 35 40 45 50-1
-0.5
0
0.5
1
Acc
eler
atio
n (g
)
Time (sec)
OpenSeesObserved
0 5 10 15 20 25 30 35 40 45 50-20
-10
0
10
20
Dis
plac
emen
t (in
)
Duration (sec)
OpenSeesObserved
PEER GMSM 16
Nonlinear Transient Analyses
The following response parameters are recorded: Peak and residual roof displacements Peak and residual interstory drift ratios Floor accelerations Beam plastic rotations (interior/exterior) Column plastic rotations
(interior/exterior) Time steps of non-convergence (if exist)