effect of modeling parameters on collapse behavior of rc
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Effect of Modeling Parameters on Collapse Behavior of RC Building
Adolfo B. Matamoros, Anil Suwal, and Andres Lepage
16th U.S.-Japan-New Zealand Workshop on the Improvement of Structural Engineering and ResiliencyNara, Japan, 27-29 June 2016
Rehabilitation Objective Modeling Parameters
Acceptance Criteria
Maximum ConsideredEarthquake
474 yrs
225 yrs
72 yrs
2475 yrs
ASCE-41Standard
FEMA P695 MethodologyEquivalent safety against collapse for buildings with different seismic force resisting systems
Collapse Safety Margin
Global InstabilityLocal Instability
Median Collapse: One-half of the structures have some form of collapse
Collapse Margin Ratio, CMR =SA Median collapse-level ground motions
SA of MCE ground motions
NEHRP: Structure should have a low probability of collapse for MCE (1.5 times the design level earthquake)
Design Criteria for Building Codes (i.e. R, Cd, and Ω0 seismic performance factors)
CMR is established through Incremental Dynamic Analysis
0.00
0.50
1.00
1.50
2.00
2.50
3.00
0 0.01 0.02 0.03 0.04 0.05
Inte
nsity
Mea
sure
Drift Ratio
1st Story
2nd Story
3rd Story
4th Story
5th Story
6th Story
-200
-100
0
100
200
0 5 10 15 20
Building Description• Seven-story RC Building in Van Nuys, CA• Designed in 1965 and constructed in 1966• Exterior moment-resisting frames• Interior gravity load flat slab system• Strong motion records from:
– 1971 San Fernando – 1987 Whittier – 1990 Upland– 1992 Sierra Madre– 1994 Northridge
• Light structural damage during the 1971 San Fernando Earthquake, severe column damage during the 1995 Northridge earthquake.
Building Plan40 x 56 cm spandrel beam around perimeter (40 x75 cm first floor)
35 x 50 cmext. columns
45 cm square int. columns
19.1 m
45.7 m
interior frame
exterior frame
N
S
Lumped Plasticity Model for Frame Structure
Moment rotation relationship for nonlinear rotational spring of second story column of RC Building
Rotation
Mom
ent
Two Node Joint Elastic ElementJoint Offset
Evaluation Ground Motion• 1994 Northridge record SE Corner E-W• PGA 0.45 g
IM 1.0
IM 2.72 IM 2.73
Collapse Simulation Results EW Direction
0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1
0
0.5
1
1.5
2
2.5
3
1st Story
2nd story
3rd story
4th story
5th story
6th story
7th story
Average
0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1
0
0.5
1
1.5
2
2.5
3
1st Story
2nd story
3rd story
4th story
5th story
6th story
7th story
Average
0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1
0
0.5
1
1.5
2
2.5
3
1st Story
2nd story
3rd story
4th story
5th story
6th story
7th story
Average
Drift Ratio
Inte
nsity
Mea
sure
0
500
1000
1500
2000
2500
0 0.02 0.04 0.06 0.08
Mom
ent (
kip
in.)
Rotation (radians)
ASCE 41-13 column ACI 369 column
0200400600800
1000120014001600
0 0.02 0.04 0.06 0.08
Mom
ent (
kip
in.)
Rotation (radians)
ASCE 41-13 beam New beam model
0 0.5 1 1.5 2 2.5
Intensity Measure
0
0.2
0.4
0.6
0.8
1
Perc
enta
ge o
f Col
umns
Exc
eedi
ng
Yield
Capping
Post-Capping
0 0.5 1 1.5 2 2.5
Intensity Measure
0
0.2
0.4
0.6
0.8
1
Perc
enta
ge o
f Col
umns
Exc
eedi
ng
Yield
CappingPost-Capping
0 0.5 1 1.5 2 2.5
Intensity Measure
0
0.2
0.4
0.6
0.8
1
Perc
enta
ge o
f Bea
ms
Exce
edin
g
Yield
CappingPost-Capping
Intensity Measure
0 0.5 1 1.5 2 2.5
Perc
enta
ge o
f Spr
ings
Exc
eedi
ng
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Yield
CappingPost-Capping
Two Node Joint Elastic ElementJoint Offset
Two Node Joint Elastic ElementJoint Offset
0
1000
2000
3000
0 0.02 0.04 0.06 0.08
ASCE 41-13columnACI 369 column
ASCE 41-13 ACI 369
Conclusions• Changes in modeling parameters for beams and columns affected
the distribution of damage of the case-study building. • The intensity measure corresponding to lateral instability for the
model with ASCE 41-13 modeling parameters was 1.63 (0.77 g), whereas the maximum intensity measure for the model with ACI 369 modeling parameters was 2.71 (1.27 g).
• The effect of beam modeling parameters on the intensity measure corresponding to lateral instability was not significant for the case-study building, although the maximum story drift ratios before lateral instability did increase by approximately 1%.
• While the intensity corresponding to lateral instability increased significantly by adopting modeling parameters representative of the mean response of component tests, the level of damage expected to occur in gravity-load frames increased significantly as well.
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