17th World Conference on Earthquake Engineering, 17WCEE
Sendai, Japan - September 13th to 18th 2020
Paper N° C002274
Registration Code: S-A01704

The 2019 Full-Scale Shake Table Test Program of Wood Dwellings
T. Nagae(1), S. Uwadan(2), C. Yenidogan(3) (4), S. Yamada(5), H. Kashiwa(6), K. Hayashi(7),T. Takahashi(8), T. Inoue(9)(1) Associate Professor, Nagoya University, nagae@nagoya-u.jp(2) Graduate Student, Nagoya University(3) JSPS Fellow, Nagoya University, cem.yenidogan@gmail.com(4) Assistant Professor, Bahçeşehir University, cem.yenidogan@eng.bau.edu.tr(5) Associate, NIKKEN SEKKEI LTD, shohei.yamada@nikken.jp(6) Senior Researcher, NILIM, kashiwa-h92ta@mlit.go.jp(7) Assistant Professor, Toyohashi University of Technology, hayashi@ace.tut.ac.jp(8) Senior Researcher, NIED, takehiro@bosai.go.jp(9)

Deputy Director, NIED, dinoue@bosai.go.jp

Abstract
The 2019 full-scale shake table test program of wood dwellings is addressed in this paper. The current Japanese seismic
design guidelines were applied and two Grade-3 index buildings were prepared. One adopted the Post-and-Beam Structure(A-building), and the other the Shear-Wall structure (B-building). A series of tests planned very different physicalboundary conditions surrounding their reinforced concrete foundations. In the first Phase 1, A-building was equippedwith a base-isolation system, while B-building represented a generic foundation constructed on real soil by preparing arigid soil box. In the second Phase 2, the foundation of A-building was firmly fixed, while cast-iron plates were installed
beneath the foundation of B-building to control the friction resistance of the foundation. In the third Phase 3, the damaged
first-story of A-building was retrofitted, and the foundation of B-building was firmly fixed. The two test buildings weredensely instrumented with both conventional and smart sensing technologies to monitor the building’s functionality.
Utility pipelines were embedded in the soil and connected to the building. The damage states of structural andnonstructural systems under each boundary condition were evaluated in a sequence of multiple strong earthquakes.
Keywords: Shaking table test, Wood dwelling, Soil-structure interaction, Functionality, Base isolation

1. Introduction
The 1995 Kobe earthquake and the 2011 Tohoku earthquake caused catastrophic damage to buildings andinfrastructure. Densely populated urban areas may induce even worse situations in future earthquakes. MEXT
(the Ministry of Education, Culture, Sports, Science and Technology) has been leading the Metropolitan
Special Project to mitigate such earthquake disasters based on unprecedented experimentations by E-Defense(the large shaking table facility) from 2005. The Tokyo Metropolitan Resilience Project was planned for theperiod from 2017 to 2022. A comprehensive test plan for current or future wood dwellings in densely populated
urban areas was proposed in this Project (Fig. 1).

Fig. 1 A proposal for experimentation on wood dwelling systems located in densely populated urban areas

17th World Conference on Earthquake Engineering, 17WCEE
Sendai, Japan - September 13th to 18th 2020

“The 2019 full-scale shake table test program of wood dwellings” is explained in this paper with themain test results. Two test buildings were designed and constructed according to the current Japanese design
guidelines. A three-story wood dwelling reflected the trends of densely populated urban areas. From theviewpoint of the resiliency and functionality of such building system, the base-isolation system is expected tominimize damage to most structural and non-structural elements. However, the requirement of clearance
surrounding the base isolation layer can be a serious problem in densely populated urban areas. Maximum
deformation of the base isolation layer should be limited by effectively equipping oil dampers. For current
normal buildings, the foundations are directly constructed on soil, and a stiff reinforced concrete flat slab has
been required recently. A variety of embedded pipelines constitute the building functionality critical toearthquake resilience. Thus, a large soil box representing 1.5 m-high soil was designed for the relevant test
series. The ground motions recorded during the 1995 Great Hanshin (Kobe) earthquake and the 2011
Megathrust Tohoku earthquake literally exceed the intensity levels considered in design practice. Japanese
Grade-3 index buildings may provide hints to overcoming the maximum-considered earthquakes in terms of
the structural and functionality aspects. Thus, a comprehensive test program was established through intense
discussions concerning these current typical issues.

2. Test Building and test schedule
Two test buildings were planned to widely cover Japanese practice. One adopted the Post-and-Beam Structure(A-building), and another the Shear-Wall structure (B-building). The Post-and-Beam Structure represents the
traditional Japanese structural system. The Shear-Wall structure is known as the Two-by-Four construction
method and is equally utilized in Japan. Regarding design and construction, the Japanese seismic grading
scheme was applied. Requirements concerning the amount of equivalent wall have been enhanced, and metal
reinforcements for connections and steel anchor bolts securing the column base have been developed andstrictly required in reference to the past seismic failure mechanism of wood buildings. Both the Post-and-Beamand Shear-Wall Structures have been improved from such point of view. Grade-2 and Grade-3 index buildings
especially have adopted the allowable stress design with a higher design base shear force; the base shear force
coefficient of 0.2 to the standard, 0.25 to the Grade-2 index building and 0.3 to the Grade-3 index building.
The design criteria of the Grade-3 index building were adopted for both of the two test buildings. The strength
margin of the design requirement was minimized to evaluate the capacities of both test buildings. Figure 2
shows the elevations of two test buildings. The two test buildings adopted identical configurations and plans.
Thus, the earthquake resisting capacities of the upper structures of A-building and B-building were assumed
to be equivalent in the design process.

Y-direction

X-direction
North elevation

Y-direction

West elevation

X-direction
South elevation

East elevation

Fig. 2 Elevations of A-building and B-building2

17th World Conference on Earthquake Engineering, 17WCEE
Sendai, Japan - September 13th to 18th 2020

The test system of B-building accommodated real 1.5 m-high soil beneath the foundation by preparing areinforced concrete soil box of 1.7 m (H) x 7.0 m (W) x 13.0 m (L), as shown in Fig. 3. Silica sand was utilized
for the soil, and each of the five layers of 250 mm were compacted individually. Figure 4 shows the setups ofA-building and B-building on the E-Defense table. Horizontally wide steel frames covered the exterior zoneof the shaking table to protect the important facilities equipped inside the outer moat. The X-direction of thetest buildings was set to the shorter direction of the E-Defense table.

(1) Reinforced concrete soil box (2) Compacted soil (3) Foundation constructed on the soil

Fig. 3 Construction of soil and foundation in the soil box of 1.7 m (H) x 7.0 m (W) x 13.0 m (L)

20 m

15 m

South

East

A-building

B-buildingWestY-direction

X-direction

North

Y-direction
X-direction

Fig. 4 Setup plan of two test buildings placed on the E-Defense shaking table
Figure 5 shows the depiction regarding the sequential tests in Phase 1, Phase 2 and Phase 3. The same
upper structures were always used; the Post-and-Beam Structure of A-building and Shear-Wall structure of Bbuilding.[1] In the first Phase 1, A-building was equipped with a base-isolation system, while B-building
represents a foundation supported on soil. The base-isolation system was composed of fifteen sliding bearings
having the friction coefficient of 0.065, six laminated rubbers and six oil dampers (three for each of the X andY-directions). The damping capacity by oil dampers was designed to fulfill a special displacement limit,
supposing a densely populated urban area. In the second Phase 2, the foundation of A-building was firmly
fixed, while twenty cast-iron plates were inserted beneath the foundation of B-building. The application of
cast-iron plates to reduce the friction resistance of the foundation, was adopted regarding the development ofan artificial input-loss system.[2] In the third Phase 3, the first-story of A-building was retrofitted, while thefoundation of B-building was firmly fixed to the rigid soil box. The test results observed in Phase 1 and Phase
2 are summarized and introduced in this paper.

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17th World Conference on Earthquake Engineering, 17WCEE
Sendai, Japan - September 13th to 18th 2020

Table 1 shows the input motion schedules in each Phase. The JMA-Kobe motion and JR-Takatori motionof the 1995 Kobe earthquake were used. JMA-Kobe 50% is equivalent to the Design-Based Earthquake. Whitenoise motion tests were conducted between the ground motion tests.

Fig. 5 Depiction regarding the sequential tests in Phase 1, Phase 2 and Phase 3
Table 1 Test schedule and input motions
Phase / Test datePhase 1January 31, 2019
February 1, 2019

Phase 2February 7, 2019
Phase 3February 12, 2019

A-Building
Post-Beam Structure

B-Building
Shear-Wall Structure

Base-isolation system

Foundation-soil system

Fixed-foundation system

Foundation-cast iron -soil
systemFixed-foundation system

Fixed-foundation system

Input motion(1) JMA-Kobe 25%(2) JMA-Kobe 50%(3) JR-Takatori 25%(4) JR-Takatori 50%(5) JMA-Kobe 100%(6) JR-Takatori 100%(7) JMA-Kobe 25%(8) JMA-Kobe 50%(9) JMA-Kobe 100%
(10) JR-Takatori 100%(11) JMA-Kobe 100%4

17th World Conference on Earthquake Engineering, 17WCEE
Sendai, Japan - September 13th to 18th 2020

X-direction

Y-direction

X-direction

Y-direction(1) JMA-Kobe 100%(2) JR-Takatori 100%
Fig. 6 Comparison of recorded motions
Figure 6 shows the recorded input motions. When subjected to JMA-Kobe 100% and JR-Takatori 100%,
the evaluations became identical at the center of the shaking table and at the top of the soil box frame.

3. Test Results of A-building in Phase 1 and Phase 2
Figure 7 shows the response acceleration time histories of the third floor when A-building was subjected to
JMA-Kobe 100%. Figure 7 (1) shows the base-isolation system in Phase 1, and Fig. 7 (2) shows the fixedfoundation system in Phase 2. Regarding the base-isolation system, the maximum acceleration value is one
fourth of the fixed-foundation case . The maximum value is less than 4 m/s2 in Phase 1 (base-isolation system),
while more than 17 m/s2 in Phase 2 (fixed-foundation system). Figure 8 shows the maximum floor acceleration
distribution in the height. Regarding the base-isolation system, the maximum floor accelerations are the samefrom the first floor to the roof floor. The incrementing degree of the floor acceleration values became smaller
between JMA-Kobe 100% and 50% than between 50% and 25%, although the shaking table input wasincreased twice between 25% and 50% as well as between 50% and 100%. This is because the developed
special dampers exhibited a higher damping factor at higher velocity. In Phase 2, the maximum accelerationof the first floor is equivalent to that of the input motion, and increases two times at the upper floor.

(Base-isolation system)(Fixed-base system)

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17th World Conference on Earthquake Engineering, 17WCEE
Sendai, Japan - September 13th to 18th 2020

(1) A-building / Phase 1 (base-isolation system)(2) A-building / Phase 2 (fixed foundation)

Fig. 8 Maximum floor acceleration distribution of A-building (X-direction)(2) A-building / Phase 2 (Fixed foundation)(1) A-building / Phase 1 (Base-isolation system)

Fig. 9 Damage A-building subjected to JMA-Kobe 100% (dinning room)

JMA-Kobe 100 %JR-Takatori 100 %(1) Displacement time history of base isolation layer (X-direction)(2) Relative displacement in the base-isolation layer while subjected to JMA-Kobe 100 %Fig. 10 Displacement time history and video capture of the base-isolation layer
The intensity of floor response is related to the damage to furniture and equipment in rooms. The test
results showed significant differences between the base-isolation system and fixed-foundation system, as
shown in Fig. 9. Most of the furniture overturned and was crushed in the fixed foundation case, while only one
drawer of the refrigerator came open in the base-isolation case. Regarding the response of the base-isolation
layer, Fig. 10 shows the relative dsplacement time history and snap shots of the large relative displacement.

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17th World Conference on Earthquake Engineering, 17WCEE
Sendai, Japan - September 13th to 18th 2020

The maximum displacement was limited to less than 150 mm during JMA-Kobe 100%. The maximum
displacement slightly exceeded 400 mm during JR-Takatori 100%.

(1) Base-isolation system (A-building, Phase 1)(2) Fixed-foundation system (A-building, Phase 2)

Fig. 11 Comparisons of the maximum inter-story drift angle distribution / A-building(2) JR-Takatori 100%(1) JMA-Kobe 100%

Fig.12 Relationship between story shear force and story drift angle at the first story
A-building (Fixed-foundation system) / Phase 2 / X-direction
Figure 11 (1) shows the distribution of the maximum inter-story drift angle of the base-isolation system(Phase 1). The inter-story drift angle was limited to less than 0.002 rad in JMA-Kobe 100%, and less than
0.003 rad in JR-Takatori 100%. Figure 11 (2) shows the maximum inter-story drift angle distribution of the
fixed-foundation system (Phase 2). The maximum inter story drift angle was limited to less than 0.008 rad in
JMA-Kobe 50%. However, when subjected to JMA-Kobe 100%, deformation of the upper structure wasconcentrated in the first story, and the maximum inter-story drift angle exceeded 0.03 rad. When subjected to
JR-Takatori 100%, the maximum inter-story drift exceeded 0.04 rad. Figure 12 shows the relationship between
the story shear force and drift angle at the first story. Peak orienting hysteretic loops were observed when7

17th World Conference on Earthquake Engineering, 17WCEE
Sendai, Japan - September 13th to 18th 2020

subjected to JMA-Kobe 100%, and the maximum story shear force reached 600 kN at the drift angle of 0.03
rad, which corresponded to the base shear force coefficient of 1.8. Pinching hysteretic loops were repeatedly
found in the following JR-Takatori 100%, as shown in Fig. 12 (2). [2]4. Test Results of B-building in Phase 1 and Phase 2
A real soil boundary condition surrounding the foundation was preproduced as the test system of B-building.
When the foundation-soil system was subjected to JMA-Kobe 100% (Phase 1), the maximum sliding
displacement of 240 mm occurred at the foundation. The maximum sliding displacement of 300 mm occurred
when subjected to JR-Takatori 100%.[1] In the case that cast-iron plates existed beneath the foundation (Phase2), the maximum sliding displacement became 1.3 times larger in JMA-Kobe 100%, and also 1.3 times in JRTakatori 100%. Figure 14 shows the typical damage under the sliding displacements of the foundation.
Embeded VP drain pipes had severe fractures, as shown in Fig. 14 (1). Polyethylene gas pipes showed highdeformability, as shown in Fig. 14 (2), and maintained the inside pressure even after JR-Takatori 100%.
Figure 15 shows the time histories of floor response acceleration at the third floor (Phase 1). Whensubjected to JMA-Kobe 100% motion, the maximum acceleration values exceeded 1.0 m/s2. The accelerationlevel is two-thirds compared to the results of A-building with the fixed-foundation system, but 2.5 times larger
than the results of A-building with the base-isolation system. Figure 16 shows the maximum floor acceleration
X-direction (Sequential test data)

JMA-Kobe100%(1) JMA-Kobe
100%
JMA 神戸波100%

Y-direction (Sequential test data)

100%(2)JR-Takatori
JR-Takatori
100%
JR 鷹取波 100%

JMA-Kobe100%(1) JMA-Kobe
100%
JMA 神戸波
100%(2) JR-Takatori
JR-Takatori
100%
JR 鷹取波 100%
100%

Fig. 13 Time history of foundation sliding in the sequential tests / Phase 1 (Foundation-soil system)(1) Fractured VP drain pipe

(2) Bent polyethylene gas pipes

Fig. 14 Typical damage of pipe lines after subjected to JMA-Kobe 100% (B-building, Phase 1)

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17th World Conference on Earthquake Engineering, 17WCEE
Sendai, Japan - September 13th to 18th 2020

distribution in the height. The maximum floor acceleration gradually increased to the roof floor, while themaximum acceleration was slightly smaller at the first floor (foundation) than at the shaking table. As a result,
furniture and equipment were significantly overturned.

Fig. 15 B-building subjected to JMA-Kobe 100% / Phase 1 (Soil and foundation) /Comparisons of floor response acceleration time histories at the third floor(1) Foundation-soil system (Phase 1)(2) Foundation-cast iron-soil system (Phase 2)

Fig. 16 Maximum floor acceleration distribution of B-building / X-direction(1) Foundation-soil system (Phase 1)(2) Foundation-cast iron-soil system (Phase 2)

Fig. 17 Maximum inter-story drift angle distribution of B-building

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17th World Conference on Earthquake Engineering, 17WCEE
Sendai, Japan - September 13th to 18th 2020

Figure 17 shows the maximum inter-story drift angle distribution of B-building. The maximum interstory drift angles were limited to less than 0.018 rad even when subjected to JMA-Kobe 100% and JR-Takatori
100% in both Phase 1 and Phase 2. As a result, the damage due to the story deformations was not significant,and minor split lines were observed on the interior walls at the first story. On the other hand, in A-building
with the fixed-foundation system, the maximum inter-story drift angle exceeded 0.03 rad when subjected to
JMA-Kobe 100% and exceeded 0.04 rad when subjected to JR-Takatori (Fig. 11). The upper structures of thetwo buildings showed comparable stiffness based on the same allowable stress design, and higher strength
capacity in A-building than in B-building.[2] The higher strength capacity of the upper structure wascorrespondent to the base shear force coefficient of 1.8 in A-building. On the other hand, the base shear force
coefficient was limited to 1.2 in B-building with the soil-foundation system.[1] These test results indicated thatthe upper structure possessing the Japanese Grade-3 capacity can induce sliding at the foundation, and resultin the upper limit to seismic forces in the upper structure. Pipeline systems should be designed to accommodate
sliding displacement.

5. Test Result Assessment by Acceleration Displacement Response Spectra Format
A series of tests provided a variety of results from different structural systems, such as the foundation-soil
system, base-isolation system and fixed-foundation system. Significant nonlinear responses in those systems
can be discussed using the Acceleration Displacement Response Spectra format, in which spectral acceleration,
Sa, is plotted against spectral displacement, Sd. The Japanese seismic design code provides a consistent designroute in conjunction with the code Sa-Sd spectra. The deformation distributions can be assessed given the firstmode shape. Regarding the assessment of test results, the first mode shapes were defined in reference to the
maximum deformation distributions. Figure 18 shows the mode vectors adopted for (1) A-building with thebase-isolation system, (2) A-building with a fixed-foundation system and (3) B-building with a foundationsoil system. By using these mode vectors, the equivalent Single-Degree-Of-Freedom systems were derived.
The response assessment for the equivalent Single-Degree-Of-Freedom systems is depicted in the
Acceleration Displacement Response Spectra format, as shown in Fig. 19. Figure 19 (1) shows the results ofA-building with the base-isolation system. The maximum displacements correspond to Sa-Sd spectra in both
JMA-Kobe 100% and JR-Takatori 100%. Figure 19 (2) shows the results of A-building with a fixed-foundation
system. The maximum displacements similarly correspond to Sa-Sd spectra. Their maximum displacementsof positive and negative sides are comparable in both the base-isolation and fixed-foundation systems. Figure
19 (3) shows the results of B-building with a foundation-soil system. The hysteretic characteristics induced
displacement drifting to one direction with a residual displacement. Since this method assumes equal
displacements on the positive and negative sides, some modifying factor may be necessary. However, themaximum displacements were quite consistent with the spectra in this test.

(1) A-building / Phase 1(Base-isolation system)(2) A-building / Phase 2(Fixed-foundation system)(3) B-building / Phase 1(Foundation-soil system)

Fig. 18 Adopted mode vectors / JMA-Kobe 100% / X-direction

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17th World Conference on Earthquake Engineering, 17WCEE
Sendai, Japan - September 13th to 18th 2020

(1) A-building / Phase 1 (Base-isolation system) / X-direction(2) A-building / Phase 2 (Fixed-foundation system) / X-direction(3) B-building / Phase 1 (Soil-foundation system) / X-direction

Fig. 19 Comparison of test results and Acceleration Displacement Response Spectra

6. Conclusions
The 2019 full-scale shake table test was planned for current and future wood dwellings. The current Japaneseseismic design guidelines were applied to three-story wood buildings. Two Grade-3 index buildings wereprepared. One adopted the Post-and-Beam Structure (A-building), and the other the Shear-Wall structure (Bbuilding). A-building with a fixed foundation had a maximum inter-story drift larger than 0.03 rad whensubjected to JMA-Kobe 100%. On the other hand, B-building, which adopted the soil foundation, had an interstory drift limited to less than 0.018 rad when subjected to the same JMA-Kobe 100%. The sliding
displacement reached 250 mm at the foundation, while the upper structure showed input loss. These tests
indicated that the upper structure possessing the Japanese Grade-3 capacity can induce sliding at the foundation,and result in the upper limit to seismic forces in the upper structure. Flexible pipelines should be installed insuch buildings. The proposed base isolation system had successful results including the performance to keep

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17th World Conference on Earthquake Engineering, 17WCEE
Sendai, Japan - September 13th to 18th 2020

furniture and equipment safe in rooms. The seismic responses of the test buildings were reasonably assessedin the Acceleration Displacement Response Spectra format. This format can be a spine in future design practice.
The resilience capacity enhancement of wood dwellings should be continuously discussed in terms of a holistic
methodology containing all structural and nonstructural systems.

7. Acknowledgements
This work is supported by the Tokyo Metropolitan Resilience Project of the National Research Institute for
Earth Science and Disaster Resilience (NIED). Collaboration on earthquake engineering research using EDefense and NHERI facilities is proceeding continuously. Construction of the test buildings was managed by
ICHIJO Co., Ltd. The relevant test affairs were administrated by the Graduate School of Environmental
Studies, Nagoya University and E-Defense, NIED.

8. References[1] T. Nagae, S. Uwadan, K. Takaya, C. Yenidogan, S. Yamada, H. Kashiwa, K. Hayashi, T. Takahashi, T. Inoue (2020):
Sliding-rocking combined actions at base foundation influencing global and local deformations of upper wood
structure. 17th World Conference on Earthquake Engineering, 17WCEE, Paper No. C002277[2] T. Takahashi, S. Uwadan, T. Nagae, C. Yenidogan, S. Yamada, H. Kashiwa, K. Hayashi, T. Inoue (2020): Stiffness,
ultimate strength capacity and cyclic loading deterioration characteristics of two different wood-structure dwellings
following the current Japanese practice. 17th World Conference on Earthquake Engineering, 17WCEE, Paper No. C002285[3] C. Yenidogan, T. Takahashi, T. Nagae, T. Inoue (2020): Seismic performance evaluation of a base isolated P&B
structure though full-scale shake table tests. 17th World Conference on Earthquake Engineering, 17WCEE, Paper No.
C004350[4] Y. Kawamata, T. Takahashi, T. Nagae (2020): Damage mechanism of PVC drainage pipe connected to house withhigh seismic performance. 17th World Conference on Earthquake Engineering, 17WCEE, Paper No. C002097[5] C. Yenidogan, R. Nishi, S. Uwadan, T. Nagae, T. Takahashi, T. Inoue, K. Kajiwara (2020): Full-scale testing of a
two-story P&B shearwall assembly under dynamic loading test protocol. 17th World Conference on Earthquake
Engineering, 17WCEE, Paper No. C003236[6] Y. L. Chung, C. Y. Ku, J. Chen, T. Nagae, K. Kajiwara (2020): Preliminary dynamic response characterization testsIII: South NCREE multi-directional shake table test for the seismic performance evaluation of the freestanding
structures. 17th World Conference on Earthquake Engineering, 17WCEE, Paper No. C002696[7] K. Hayashi, A. Yamada, Y. Komiya, T. Nagae (2020): Cost-effective smart sensing technologies to monitor the
residential building systems. 17th World Conference on Earthquake Engineering, 17WCEE, Paper No. C002857[8] M. Koliou, M. Aghababaei, T. Nagae, C. Pantelides, K. L. Ryan, A. Barbosa, S. Pei, J. W. van de Lindt, S. Dashti(2020): Rapid damage assessment procedure to collect, process and analyze data for monitoring of full-scale tests.
17th World Conference on Earthquake Engineering, 17WCEE, Paper No. C002971

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