Upload
vodien
View
269
Download
3
Embed Size (px)
Citation preview
ASCE 7ASCE 7 10 Seismic Provisions10 Seismic ProvisionsASCE 7ASCE 7--10 Seismic Provisions10 Seismic Provisions
TimeTime--History Scaling for 3History Scaling for 3--D Dynamic AnalysisD Dynamic AnalysisLiquefaction ProvisionsLiquefaction Provisions
SiteSite--Response Analysis for LiquefactionResponse Analysis for Liquefaction
Model CalibrationModel CalibrationArray Data & ResultsArray Data & Results
C. B. CrouseC. B. CrouseURS CorporationURS CorporationURS CorporationURS Corporation
2008 USGS S2008 USGS S and Sand S Maps in ASCE 7Maps in ASCE 7 10 will be10 will be2008 USGS S2008 USGS SSS and Sand SII Maps in ASCE 7Maps in ASCE 7--10 will be10 will be
H2
n( g
)
Max Sa
a H1
t 1 d f
Acc
.in
Hdi
r ect
ion
a H2
t 1 d.o.f.
H1Acc. in H1direction (g)
at
H1
H2
2002 USGS S and S Ground Motion Maps in ASCE 7 05 are2002 USGS SS and SI Ground Motion Maps in ASCE 7-05 are
S * S ( t i )Sa1 * Sa2 (geometric mean)
Geometric Mean = SaGeometric Mean = Sa * Sa* SaGeometric Mean = SaGeometric Mean = Sa11 * Sa* Sa22
AccelerogramHorizontal Components
Response Spectra
a H1
t
H1Sa
Sa1
a H2
t
H2SaTi
T
at Sa2
TT
Ti
Geomean Sa vs Max SaGeomean Sa vs Max SaGeomean Sa vs Max SaGeomean Sa vs Max Sa
Bedrock Response Spectra
x 1.1
Based on:
Sa x 1.3 Max Sa
Geomean Sa
1.0T (sec)
TimeTime--History Scaling for H1 and H2 components History Scaling for H1 and H2 components ––y g py g p3D Analysis3D Analysis
ASCE 7-05 ASCE 7-10
ave. SRSS Sa of scaleda(t) records
ave. SRSS Sa of scaleda(t) records - R 5 km
orave. Sa of scaled FN comp.of a(t) records R < 5 km
>
Sa1.3 x Target Sa
Target
of a(t) records - R < 5 km
1.5 TPeriod (sec)
Target(geomean Sa)
0.2 T 1.5 TPeriod (sec)
Target(max Sa)
0.2 T( )
GroundGround Motion RecordsMotion RecordsGroundGround--Motion RecordsMotion Records
Design Ground Motion Libraryg y
Transform FN & FP a(t) into X & Y a(t)Transform FN & FP a(t) into X & Y a(t)Transform FN & FP a(t) into X & Y a(t)Transform FN & FP a(t) into X & Y a(t)
Fault
Liquefaction AssessmentLiquefaction AssessmentLiquefaction AssessmentLiquefaction Assessment
ASCE StandardASCE Standard77--0505
GroundGround--Motion ParameterMotion ParameterSSSS / 2.5/ 2.5
77--1010 PGA (geomean)PGA (geomean)ffforfor
Site ClassSite Class
MCE Geometric Mean PGA, %g, Site Class BMCE Geometric Mean PGA, %g, Site Class B
Site Coefficients FSite Coefficients F
Mapped Ma im m ConsideredSite
Site Coefficients FSite Coefficients FPGAPGA
Mapped Maximum Considered Geometric Mean Peak
Ground Acceleration, PGA
SiteClass
A 0 8 0 8 0 8 0 8 0 8
PGA 0.1
< PGA =0.2
PGA =0.3
PGA =0.4
PGA >0.5
ABC
0.81.01.2
0.81.01.2
0.81.01.1
0.81.01.0
0.81.01.0C
DE
1.21.62.5
1.21.41.7
1.11.21.2
1.01.10.9
1.01.00.9
F See Section 11.4.7Note: Use straight-line interpolation for intermediate values of PGA.
Site Response AnalysisSite Response Analysis Liquefiable SoilsLiquefiable SoilsSite Response Analysis Site Response Analysis –– Liquefiable SoilsLiquefiable Soils
1964 M7.5 Niigata, Japan, Earthquake Damage from 1964 M7.5 Niigata, Japan, Earthquake Damage from g , p , q gg , p , q gLiquefactionLiquefaction
1964 M 7.51964 M 7.5NiigataNiigata
Onset
Niigata Niigata EarthquakeEarthquake
Liquefaction Onset~ 8-10 sec afterstart of strongstart of strongshaking
2003 M 8 3 Tokachi2003 M 8 3 Tokachi oki Japan Earthquakeoki Japan Earthquake2003 M 8.3 Tokachi2003 M 8.3 Tokachi--oki, Japan, Earthquakeoki, Japan, Earthquake
HKD 086
FaultRupture
2003 M 8.3 Tokachi2003 M 8.3 Tokachi--oki Earthquakeoki EarthquakeHKD 086 NS CompHKD 086 NS CompHKD 086 NS Comp.HKD 086 NS Comp.
0.4
0.6
liquefaction onset –upper 10m fine sand
-0.2
0.0
0.2
a-g
-0.8
-0.6
-0.4
25 30 35 40 45 50 55 6025 30 35 40 45 50 55 60t - sec
2.5
3.0
3.5
2.9 g @ T = 0.36 sec
ξ = 5%
1.0
1.5
2.0
Sa-g
0.0
0.5
1.0
0 0.5 1 1.5 2 2.5 3 3.5 4T - sec
Acceleration Response to HKD 086 NS CompAcceleration Response to HKD 086 NS CompAcceleration Response to HKD 086 NS Comp.Acceleration Response to HKD 086 NS Comp.
3
4
2 9g
1
0
1
2
3
a-g
2.9g
-4
-3
-2
-1
25 30 35 40 45 50 55 60
-2.9g
T = 0.36st - sec
0.2
0.4
0.6ξ = 5%
-0.4
-0.2
0.0a-g
-0.8
-0.6
25 30 35 40 45 50 55 60t - sec
Soil PropertiesSoil Properties Liquefied LayerLiquefied LayerSoil Properties Soil Properties –– Liquefied LayerLiquefied Layer
or G (or Vs), d –or G (or Vs), d constants
GroundGround--Motion DataMotion DataSiteSite--Response CalibrationResponse Calibration
Port Island, Japan. 1995 Kobe M 6.9Port Island, Japan. 1995 Kobe M 6.9Wildlife Array, CA. 1987 Superstition Hills M 6.6Wildlife Array, CA. 1987 Superstition Hills M 6.6
Port Island, JapanPort Island, Japan, p, pVertical Accelerometer ArrayVertical Accelerometer Array
-10
-20
-30
-40
(m)
-50
-60Dep
th
-70
-80
0 20 40 600 200 400SPT N values V (m/s)SRef: Elgamal et al. (1996)
Port Island Array EW RecordsPort Island Array EW Recordsyy1995 M 6.9 Kobe Earthquake1995 M 6.9 Kobe Earthquake
Ref.: Davis & Berrill (1998)
Port Island Port Island –– 1995 Kobe Earthquake1995 Kobe EarthquakeqqVVSS versus Timeversus Time
Depthp
0 mm
)
16 m
spla
cem
ent (
m
32 m
Dis
Ref.: Davis & Berrill (1998)
Port Island Port Island –– 1995 Kobe Earthquake1995 Kobe EarthquakeqqVVSS versus Timeversus Time
400
300
m/s
ec)
100
200
V(m
S
0
100
0 10 20 30 400 10 20 30 40Time (sec)
Ref: Elgamal et al. (1996)
Location Map of Wildlife ArrayLocation Map of Wildlife ArrayLocation Map of Wildlife ArrayLocation Map of Wildlife Array
Ref.: Holzer & Youd (2007)
Wildlife Array InstrumentationWildlife Array InstrumentationWildlife Array InstrumentationWildlife Array Instrumentation
99
V (m/sec)S
116116-141
168
Ref: Bennett et al. (1984)Holzer & Youd (2007)
Wildlife NS AccelerogramsWildlife NS Accelerogramsgg1987 M 6.6 Superstition Hills EQ1987 M 6.6 Superstition Hills EQ
200
Surface 0
m/s
ec/s
ec
-200200
cm
Downhole 0
cele
ratio
n
-200
Acc
10 20 30 40 50 60 70 80 90Ti ( )
Ref.: Zeghal & Elgamal (1994)
Time (sec)
Wildlife Wildlife –– 1987 Superstition Hills EQ1987 Superstition Hills EQppVVSS versus Timeversus Time
(m/s
ec)
V
S
Ref.: Zeghal & Elgamal (1994)
Estimation of Material Damping Ratio (ξ) Estimation of Material Damping Ratio (ξ) p g (ξ)p g (ξ)Liquefied SoilLiquefied Soil
a(t) recordsfrom
Port Is. & Wildlife
ξ ~ 20%ξ
Wildlife SiteWildlife SiteSurface Accelerograph StationSurface Accelerograph Station
USGS El Centro Station 6USGS El Centro Station 6USGS El Centro Station 6USGS El Centro Station 6
0
Y
1.22 m
0.51 m
2
4
6
-m
1.14 m
8
10
12
Dept
h-
X
Z recorded a(t)free field14
0 100 200 300 400
V – m/secS
X
0.100.15
( )ee e da (t)
Experimental Transfer Function (low strain)Experimental Transfer Function (low strain)Experimental Transfer Function (low strain)Experimental Transfer Function (low strain)
2
Station 6
1Recorded
Free Field
010 20 30 40 50 60
f - HzRef. Crouse & Hushmand (1989)
Approximate Transfer Function (liquefaction)Approximate Transfer Function (liquefaction)pp ( q )pp ( q )VVSS
liqliq = V= VSSlow strainlow strain, Pad Thickness = 6”, Pad Thickness = 6”1
10
2
Station 6
1Recorded
Free Field
01 2 3 4 5 6
f - Hz
Approximate Transfer Function (liquefaction)Approximate Transfer Function (liquefaction)pp ( q )pp ( q )VVSS
liqliq = V= VSSlow strainlow strain, Pad Thickness = 12”, Pad Thickness = 12”1
10
2
Station 6
1Recorded
1Free Field
0 1 2 3 4 5 6f - Hz
Site Response Analysis Site Response Analysis p yp y(liquefaction & non(liquefaction & non--liquefaction cases)liquefaction cases)
Saoa
T Ratio, Sao Sa
i
i1
non-liquef.
Sai
T
Tliquef.
T
SummarySummarySummarySummary
New Seismic Provisions in ASCE 7New Seismic Provisions in ASCE 7--1010
1. 3-D Dynamic Analysis – Accelerogram Scaling
Scale SRSS to Target Sa (not 1.3 X Target Sa)
2. Ground-Motion Parameter for Liquefaction
Geomean PGA (not S / 2 5 or S / 2 5)Geomean PGA (not SDS / 2.5 or SS / 2.5)
Summary (con’t )Summary (con’t )Summary (con’t.)Summary (con’t.)
Liquefied Soil Parameters for Equivalent Linear Liquefied Soil Parameters for Equivalent Linear SiteSite--Response AnalysisResponse Analysis
Use Vertical Accelerometer Array Data
V = 15 30 m/sVS = 15 – 30 m/s
ξ ~ 20% w/o Port Island &Wildlife
soil-pad interaction