STABILITY EVALUATION OF SERMO DAM, YO GYAKARTA, USING TWO COMPONENTS

ACCELERATION TIME HISTORIES CAUSES BY JAVA SUBDUCTION EARTHQUAKE SCENARIOS.

Windu Partono, Undayani Cita Sari

4th International Conference on Rehabilitation and Maintenance in Civil Engineering

Function

Dimension

Itaipu Dam in Parana River →supply electricity in Brazil & Paraguay

Earthquake Disaster

✓ The Aceh earthquake on 26 December 2004 was an earthquake in the sea and had a magnitude of 9.2 Mw which also caused a tsunami.

✓ The Yogyakarta earthquake was happened on 27 May 2006 with magnitude moment, 6.3 Mw.

Background

To evaluate the stability of Sermo dam due tosouth Java subduction earthquake scenarios.The analysis was performed by conductingtwo component acceleration time histories(North-South/NS and East-West/EWdirections) causes by four subduction sourceearthquake event scenarios as a seismic loadto dam structure..

Research Objective

Sermo Dam Position

No Soil and Rock Parameters Bedrock Shell Transition Filter Core

1γsaturated (kN/m3) 21.82 21.00 21.70 21.00 18.74

γunsaturated (kN/m3) 20.12 20.00 21.60 18.50 15.41

2 Cohesion ( C ) (kN/m2) 680 0.001 0.001 0.001 8.3

3 Friction Angle (ø) (degree) 55 43 35 35 32

4 Permeability Coeff. (k) (m/day) 8.53 12154.69 14.292 134.1 2.32 x 10-4

5 Young’s Modulus € (kN/m2) 320000 200000 150000 150000 100000

6 Poisson’s ratio (u) 0.45 0.35 0.30 0.30 0.45

7 Vs (m/s) 231 148 171 187 158

8 Vp (m/s) 768 491 357 458 330

Sermo Dam Model

Fault

Dimodifikasi dari Irsyam 2011

Data Analysis (Response Spectral Matching)

Due to uncompleted data related with theacceleration time histories from Javasubduction source, all acceleration timehistories used in this study were collectedfrom international ground motion databases.All acceleration time histories cannot directlybe used for dam stability analysis. Allacceleration time histories should be matchedwith the seismic mechanism of Javasubduction source.

Fault

Modified Ground motion

due to LasemFault

SpectralMatching Analysis

Calculate Target Spectral for specific earthquake

M1 and R1

Select Ground Motion in Terms of Acceleration Time

Histories For Scenario M and R

Dimodifikasi dari Irsyam 2011

Data Analysis (Response Spectral Matching)

Fault

Acceleration Time Histories Data

Seismic SourcesEpicentre Distance

(Km)Magnitude

(Mw)

Illapel, Chille (2015) 235 Km 8.3

Kodiak, Alaska (2018) 281.4 Km 7.9

South Sumatera, Indonesia (2007)

394 Km 8.4

Mentawai, Indonesia (2007)

167.7 Km 7.9

Fault

Analysis Results

-0.04

-0.03

-0.02

-0.01

0

0.01

0.02

0.03

0.04

0.05

0 10 20 30 40 50 60 70 80 90 100 110 120

Accele

rati

on

(g)

Time (s)

Two Component Acceleration Time South Sumatera Earthquake

Original NS

Original EW

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

0 20 40 60 80 100 120 140 160

Accele

rati

on

(g)

Time (s)

Two Component Acceleration Time Histories Mentawai Earthquake

Original EW

Original NS

Original acceleration

time histories for South

Sumatera and Mentawai

Earthquake

Fault

Analysis Results

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

0 0.5 1 1.5 2 2.5 3 3.5 4

Acc

eler

ati

on

(g

)

Period (s)

Spectra Target for South Sumatera Earthquake

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 3.5 4

Accele

rati

on

(g

)

Time (s)

Spectra Target for Mentawai Earthquake

Spectral Target for South

Sumatera and Mentawai

Earthquake

Fault

Analysis Results

-0.2

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

0.2

0 10 20 30 40 50 60 70 80 90 100 110 120

Acc

eler

atio

n (g

)

Time (s)

Two Component Acceleration Time Histories South Sumatera Earthquake

Matched NS

Matched EW

-0.1

-0.08

-0.06

-0.04

-0.02

0

0.02

0.04

0.06

0.08

0.1

0 20 40 60 80 100 120 140 160

Accele

ra

tio

n (g

)

Time (s)

Two Component Acceleration Time Histories Mentawai Earthquake

Matched EW

Matched NS

Matched acceleration time

histories for South Sumatera and Mentawai

Earthquake

Fault

Analysis Results

Position of displacement and PGA measurements

Fault

Analysis Results

Displacement of core zone measured

100

105

110

115

120

125

130

135

140

145

0 0.1 0.2 0.3 0.4 0.5 0.6

Da

m E

lev

ati

on

(m

)

Displacement (m)

Displacement At Core Zone

Vertical Displacement

Horizontal Displacement

Total Displacement

Fault

Analysis Results

PGA profiles at core position

110

115

120

125

130

135

140

145

1E-09 1E-08 1E-07 1E-06 1E-05 0.0001 0.001

Dam

Ele

vati

on

(m

)

PGA (g)

PGA Profile At Core ZoneChile EW

Chile NS

Alaska EW

Alaska NS

Mentawai EW

Mentawai NS

Sumatera Selatan EW

Sumatera Selatan NS

Fault

Comclusions

1. Based on the total displacement results calculated using four earthquake scenarios and the results calculated for original dam condition without earthquake loads it seems that all displacement analysis results are almost equal.

2. The maximum PGA value investigated at core zone of dam is 0.0001 g.

3. Sermo dam is predicted strong enough to resist earthquake causes by Java subduction megathrust earthquake with maximum magnitude 8.4 Mw and minimum epicentre distance approximately 160 Km.

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