DEVELOPMENT OF RESILIENT REINFORCED
CONCRETE PUBLIC APARTMENT BUILDINGS BY
USING WALL ELEMENTS INCLUDING
NON-STRUCTURAL WALLS FOR DAMAGE
REDUCTION IN EL SALVADORWilliam Roberto GUZMAN CALDERONMEE17718

Supervisor: Dr. Koichi KUSUNOKI

ABSTRACTIn El Salvador, public apartment buildings have been designed using structural systems based on
reinforced concrete block masonry wall or reinforced concrete moment-resisting frames that usually
have non-structural walls. However, no design methodology has been proposed to date to consider theeffect of non-structural walls, and it is still a common practice not to treat walls with large openings as
structural walls, and their capacity is usually discarded in the design of the building. Past earthquakes
have revealed that the structural systems mentioned above had a high level of damage to theircomponents. Therefore, to obtain practical and economic structures of resilient buildings, this study
proposes to use a new construction method recently developed in Japan that has not been used yet in
El Salvador. For the implementation of the new construction method, first a methodology of designand numerical model was proposed, then, the accuracy of the model used was verified through thecomparison with experimental data obtained from a full-scale static loading test on a five-story
building, performed by the Building Research Institute (BRI) of Japan. Finally, with the appropriate
numerical model, the seismic performance of the Target Building was improved by considering theeffect of the non-structural walls. From these three aspects, the Target Building was designed in thisstudy, which is planned for construction in 2019 in El Salvador.
Keywords: Resilience, Public Apartment Buildings, Wing Wall, Performance-Based Design.
1. INTRODUCTION
The Ministry of Public Works has planned for 2019 the construction of new public apartmentbuildings. However, the area where the Project will be developed is considered one of the zones within
the Metropolitan Area of San Salvador with high seismic hazard. Also, the type of buildings
considered for the Project (buildings between three and six-story) can have a seismic over-demand as aresult of the amplification of the seismic wave related to site effects. These two factors can put at risk
the success of the Project, but more important, can put in danger the lives of people if these buildings
are not designed properly. Therefore, in this study it is proposed to apply the concept of resilience tothe design and construction of public apartments buildings from two perspectives:
1. Contribute to the process of updating the Seismic Code of El Salvador by proposing an alternative
seismic design methodology using Performance-Based Design and apply it in the design of RC
Public Apartment Buildings.

Ministry of Public Works, Transport, Housing and Urban Development, El Salvador.
Assoc. Professor, Earthquake Research Institute (ERI), University of Tokyo, Japan.

12. Use new construction methods framed
within the conventional structural design,
which may be economically more feasible in
El Salvador compared to newly technology
such as damper system or base isolation
system. The above, with the objective ofimprove the seismic performance of Target
Building by using wall elements including
non-structural walls (see Figure 1).
For the application of the design
methodology and the new construction method,from a Project which currently being executedby the MOP, it was selected a public apartment
as Target Building (see Figure 2).

Figure 1. Enhancing the Seismic Performance ofTarget Building.

Figure 2. Elevation and plan view of Target Building.
2. METHODOLOGY
For the final design of the Target Building, the seismic design forces were first established using thePerformance-Based Design philosophy. Then a numerical model was developed which was calibratedusing experimental data. Subsequently, with the model created, the design of the Target Building wascarried out, proposing a new construction method to improve the performance of the building
compared to the original design established in the Project profile.
3. PERFORMANCE-BASED DESIGN
Vertical Distribution of Base Shear
6Force Based Design(FBD)
Displacement Based
Design (DBD)

54Story

The determination of the Base Shear was made using the methods
based on force (FBD) and displacement (DBD). The performance
objectives used in the design are shown in Figure 3. For the designof the Target Building, the forces coming from the Direct
Displacement-Based Design method were selected (see Figure 4).

32
10050

100150

Shear (kN)

200250300

Figure 4. Comparison between
Base Shear calculated with FBD
and DBD for one frame.
Figure 3. Design objectives.

24. NUMERICAL SIMULATION OF REINFORCED CONCRETE MOMENT-RESISTINGFRAMES INCLUDING NON-STRUCTURAL WALLS
A numerical model was developed using the CANNY
software, taking into account the following
considerations:
Modeling of global system
The joints between columns with wing wall and beams
are modeled as rigid zone, and the critical section of eachstructural element is established at the end of the edge ofthe rigid zone (see Figure 5).
Modeling of local system
Beam element is designed as a 2D line element withuniaxial bending and shear springs (US model). Two
uniaxial hysteresis models were used. Both hystereticmodels can be seen in Figures 6 and 7 (Li Kangning,2018).

Figure 5. Global system for the specimen.

Figure 6. Flexural spring: Cross-peak trilinear Figure 7. Shear spring: Cross-peak trilinear
model (CP3).
pinching model (CP7).
The column element is idealized by 3D beam line model. For nonlinear analysis, themultiaxial spring model (MS model) has been used for each material. For concrete and steel material,
two hysteresis models were selected for each. Hysteretic models can be seen in Figures 8, 9, 10 and 11(Li Kangning, 2018).

Figure 8. Concrete uniaxial spring model (US): Figure 9. Concrete multiaxial spring model (MS):Trilinear model (CS3).
Exponential function model (CS4).

Figure 10. Steel uniaxial spring model (US): Figure 11. Steel multiaxial spring model (MS):Trilinear/bilinear model (SS3).
Tanaka-CANNY (SR4).

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The collision between the non-structural walls was represented by a shear spring applied toa diagonal line element. For the shear spring, a symmetric model was used which is an adapted versionof the Multi-Linear Elastic Model with Gap (EM0). The shear spring models EM0 is shown in Figure12 (Li Kangning, 2018). To see the behavior and failure mechanism of one of the interior columns
with wing wall (in the 1st story) of the Target Building, a numerical simulation using FEM wasperformed with the general purpose finite element program LS-DYNA (see Figure 13).

Figure 12. Shear spring model EM0 for Figure 13. Finite element model of column withcollision of a non-structural wall.
wing wall.
5. DESIGN OF TARGET BUILDINGIn the profile of the Project it was established to construct the building using reinforced concrete block
masonry wall, however this proposal was revised in this study and it was found that the building does
not meet the expected low level of damage. Thus, to reduce the expected damage, a new construction
method was applied to the Target Building, which is 100% adjusted to the architectural plan of theProject, that is, no dimension or distribution of spaces were modified (see Figure 14).

Figure 14. Plan view and elevation view of Target Building. Moment-resisting frame with wall
elements and non-structural walls.
Figure 15 shows the overall analysis model of the system composed of columns, beams andnon-structural walls, used for the design of the Target Building.

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Figure 15. Overall analysis model for Target Building.
6. RESULTS AND DISCUSSION
Load-displacement relation (BRI Test)
7000
6000

Collision of nonstructural walls

5000
4000

Base Shear (kN)In Figure 16 it can be seen that thenumerical simulation has good agreementwith experimental result regarding: Initial stiffness.
 Maximum strength and maximum
displacement.
 The point which the mullion walls
firstly hit against spandrels on thebeam.
Figure17showstheperformance of the Target Building,where it is observed that when the effectof non-structural walls was included, theseismic performance was increased,taking into account that the mechanismof failure of the building changed fromductile to brittle.

-3.50

3000

Experimental 2000
Results
1000
-3.00

-2.50

-2.00

-1.50

-1.00

0-0.50
0.00
-1000
-2000

-3000
-4000

0.50

1.00

1.50

2.00

2.50

3.00

3.50

NumericalSimulation

-5000

-6000
-7000

Total drift(%)

Figure 16. Comparison between numerical simulation andexperimental results in specimen tested by BRI.

Bare Framebuilding
Building withwing wall

Figure 17. Improvement of the seismic performance of Target Building.
With the results obtained from the FEM analysis, it was confirmed that for the interior
column of the Target Building, the steel reinforcement at wall edge of the wing wall yielded in tension
side and suffered buckling in compression side, causing the spalling of the concrete. The way to avoid
the yielding and buckling of steel reinforcement at the edge of the wing walls is under investigation inJapan, and there is a proposal developed in KUSUNOKI Lab that consists in inserting a seismic slit at
the base of the wing wall and cutting the steel reinforcement at that point (see Figure 18). To study theeffectiveness of this proposal, in 2019 a full-scale test will be carried out.

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Figure 18. Failure mechanism of the column with wing wall and proposed modification.
7. CONCLUSIONS Compared to FBD, the DBD method increases the seismic load in the building by 25%.
 The numerical simulations performed have good agreement with the experimental results, so theanalytical models used in this study are effective to evaluate the seismic performance of RC
moment-resisting frame including the effect of non-structural walls.
 In this study it has been demonstrated experimentally (through the full-scale test conducted byBRI) and analytically verified (with the developed numerical model) that the RC non-structuralwalls would increase the stiffness and strength of the RC moment-resisting frames, indicating thatthe non-structural wall effects should be considered in the performance-based seismic design.
 When the new construction method used in this study wants to be considered, it is possible toquickly evaluate the effect of the non-structural walls in the Bare Frame building through thefollowing factors deduced from the analysis:- Increase the strength of the Bare Frame building, by multiplying with 1.85.
- Decrease the ultimate displacement of Bare Frame building, by multiplying with 0.65.
 It should be kept in mind that when considering the effect of non-structural walls on building
performance, the structure failure mechanism is changed from a ductile failure to a brittle failure.
 It was verified that the columns with the wing wall would show strength deterioration after
compression failure of the end section of the wing wall. Also, the column with the wing wall canalso present a shear failure. However, because the RC moment-resisting frames with wall elements
and non-structural walls is essentially a frame system, the building shows ductile behavior until
maximum capacity because the contribution of the beams is dominant.
8. RECOMMENDATION
Further studies and experimental data should be done to improve the numerical models that include theeffect of non-structural walls in RC moment-resisting frames.
ACKNOWLEDGEMENTS
I would like to express my sincere gratitude to my supervisor Dr. Koichi KUSUNOKI and myadvisors Dr. Haruhiko SUWADA and Dr. Tatzuya AZUHATA for the support and advice they gaveme during my study. Also, I want to give special thanks to Dr. Kangning Li for providing me verykindly his program CANNY to use it in my research.
REFERENCES
Kabeyasawa, T., Mukai, T., Fukuyama, H., Suwada, H. and Kato, H., 2017, Full-Scale Static Loading
Test on a Five-Story Reinforced Concrete Building (Part1: Outline of the Test), 16th World
Conference on Earthquake, Santiago Chile, Paper N° 1242.
Li Kangning, 2018, CANNY Three Dimensional Nonlinear Static and Dynamic Structural Analysis
Software, Technical and User Manuals.
Priestley, M., Calvi, G. and Kowalsky, M., 2007, Displacement-Based Seismic Design of Structures,
Pavia, Italia: IUSS Press.

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