PERFORMANCE BASED LIMIT STATES FOR INFILL WALLS

IN RC FRAMES

İsmail Ozan DEMİREL1, Ahmet YAKUT2, Barış BİNİCİ3, Erdem CANBAY4

ABSTRACT

Relation between displacement demand and corresponding damage on structural members are needed to be

clarified in order to apply performance based engineering concepts. To that end, performance limit states are

defined for reinforced concrete (RC) members in terms of level of plastic rotation. Being practically defined as

non-structural members in most of the recent earthquake resistant design codes, infill walls are simply ignored in

performance assessment. According to EC8, damage limitation requirement for infill walls are considered to be

satisfied when the inter-story drift demands do not exceed certain limits in each story of the building. However,

the earthquake resilience of RC building frame systems is significantly influenced by the presence of infill walls

based on the earthquake aftermath observations. Infill walls may be beneficial for small deformation demands in

providing additional rigidity and strength. The performance limit states of the frames with infill walls are not

established to date. Neglecting the presence of infill walls and trying to estimate building vulnerability based on -

relatively well established- performance states of RC members alone may mislead the earthquake hazard

mitigation studies. In this research, an extensive experimental campaign was carried out to define performance

limit state definition of traditional infill walls as well as strengthened infill walls with different techniques. 8

identical code designed, half scale, single RC frames were infilled with different materials and techniques and

exposed to increasing in-plane cyclic displacement reversals up to 4% drift level. In addition to hysteretic responses

and propagation of damages, performance limit states with respect to inter story drift is determined by joint

treatment of visual and structural damages.

Keywords: Experimental Testing; RC Frame; Infill Wall; Performance Limit State; Strengthening

1. INTRODUCTION

Infill walls are widely used inside reinforced concrete buildings for the purpose of partitioning the

structural space, creating healthy indoor environment, heat, moisture, sound isolation and providing

space for installations. Durable nature, ease of construction and low cost results in widespread use of

brick masonry for infill wall construction especially for residential buildings. Although infill walls laid

inside reinforced concrete frames are passive members under gravity loading, they are activated in case

of lateral loads. Contribution of infill walls on the strength and stiffness of the bounding RC frames are

a topic of interest for earthquake engineering community since 1960's (Polyakov, 1956). But still, sound

analytical solutions or simple structural models have not been proposed. Most of the well-known

contemporary earthquake design codes including Eurocode still treat infill walls as non-structural

members and ignore their contribution. The design of infilled RC buildings is usually performed on

elastic bare frame models, where the infill walls are considered in terms of masses and vertical loads.

Infill walls are only checked against out-of-plane stability.

1Graduate Student Researcher, Dept. of Civil Engineering, METU, Ankara, Turkey, odemirel@metu.edu.tr 2Professor, Dept. of Civil Engineering, METU, Ankara, Turkey, ayakut@metu.edu.tr 3Professor, Dept. of Civil Engineering, METU, Ankara, Turkey, binici@metu.edu.tr 4Professor, Dept. of Civil Engineering, METU, Ankara, Turkey, ecanbay@metu.edu.tr

2

Controversial arguments have been raised on the role of infill walls regarding the seismic performance

of infilled RC frames. On one hand infill walls have the potential to provide additional base shear

capacity and reduce drift demand of a building lacking adequate strength and stiffness, but on the other

hand their irregular distribution on plan or along the height of the building may result in fatal outcomes

such as soft story and short column failures and their additional thrust on bounding columns might result

in unexpected shear failures. Some researchers (Bertero and Brokken 1983) claimed that usual trend is

to neglect infill walls during the design, so they serve as a reserve capacity increasing the stiffness and

the strength of the RC frames and provide better deformation control for the structure. Other researchers,

on the other hand, claim that presence of infill walls may violate the seismic design philosophy for frame

action due to additional trust created by the compressed infill strut (Langenbach 1987). Presence of infill

walls changes the dynamic properties, ductility and energy dissipation capacity (Negro and Verzeletti

1996). Their role can be positive, provided that their arrangement in-plan and in-elevation is adequate

and that their effect on the building response is taken into account in the design phase (Rodriguez et al

2008). But, improper arrangement of infill walls may lead to unfavorable seismic behavior.

Experimental research (Mehrabi et al. 1996) and analytical investigations (Nicola et al. 2015) showed

that improper arrangement of infill walls might result in abrupt change of stiffness, resulting in short

column and soft story failures or the infill walls may collapse in out of plane direction and pose threat

to human life.

RC buildings infilled with walls is one the most predominant construction type in Turkey. Due to its

practicality, currently infill walls with perforated clay bricks are constructed with plaster without any

special connection to the bounding frame. This results in poor seismic performance of existing systems

(Figure 1). Recent earthquakes (Kocaeli 1999, Van 2011) demonstrated the vulnerability of infilled RC

frames that they are very susceptible to damage under low to moderate earthquakes and they might be

critical for the stability of highly damaged buildings under severe earthquakes. In addition to infill walls

structural role under seismic actions, economical and physiological effects of infill damage should not

be underestimated (Sucuoğlu, 2013). The interviews after devastating earthquakes showed that the

inhabitants had a resistance to live in their apartments and tended to move to another safe place, despite

the fact that damage was non-structural and limited to the cracking of the infill walls (EERC 2011,

EERC 2012). Therefore, there is a need to understand and revise the design and construction practice

regarding the performance of the infill walls in RC frames and develop new infill wall solutions that are

suitable to current practice in Turkey.

Figure 1. Severe infill damage after Mw=7.2 Van Earthquake (2011), Turkey

In the current performance based engineering practice, building performance is generally determined

based solely on the performance of RC elements. Recently developed seismic assessment guidelines are

3

calibrated with the test data to estimate the deformability of RC components. Despite the efforts to

estimate the damage based solely on RC elements, it is perhaps equally important to estimate the

stiffness contribution, strength and deformability of infill walls to estimate the damage state of an RC

frame equipped with brick infill walls. In this regard, it should be emphasized that modern seismic

design and assessment philosophy based solely on ductility concepts of members may be inadequate to

estimate the actual expected damage unless they account for the contribution of infill walls. Neglecting

the presence of infill walls and trying to estimate building vulnerability based on relatively well

established performance states of RC members alone may mislead the earthquake hazard mitigation

studies. Noting this urgent need in the earthquake engineering community, an extensive experimental

campaign on half scaled RC frames infilled with traditional and new techniques have been conducted to

better understand infill wall behavior, estimate performance limit states for the infilled frames and

improve the infill wall performance for earthquake resilience. A total of 9 in-plane cyclic tests are

conducted on code designed, half scaled RC test frames infilled with different materials and construction

techniques such as generating horizontal slip planes with ties or locking bricks, reinforcing plaster with

steel or fiber meshes.

2. INFILLED TEST FRAMES

RC frame specimen to be infilled with different techniques for laboratory testing is determined

considering the single-story, single bay frame being part of a bottom story of a regular 5-storey building

designed according to Turkish Earthquake Code (2007) high ductility class. Building is assumed to be

located in seismic zone 1 (PGA=0.4g) and soil class Z2. Capacity design and strong column - weak

beam principles are taken into account in seismic design. Effective slab width is accounted including

slab reinforcements. Due to the laboratory limitations, actual frame is scaled to the half keeping the axial

stress and reinforcement ratios almost the same as the reference building. Due to scaling column and

beam dimensions of the tested frames are reduced to 200mm x 200mm and 150mm x 200mm

respectively. Top 70 mm of the beam is flanged due to slab. Slab width is 1000 mm. Clear cover from

edge to the rebar center is 20 mm for all members. Deformed bars with 8mm nominal diameter is utilized

for longitudinal reinforcement whereas plain bars with 6mm nominal diameter is utilized for transverse

reinforcement (Figure 2).

Figure 2. Geometry and detailing of RC test frame

The first specimen tested under in-plane loading was bare frame enabling assessment of infill

contribution to in-plane response. After RC frames infilled with traditional techniques and materials

such as perforated clay brick and auto aerated concrete was tested, new techniques were proposed aiming

at better in-plane as well as out-of-plane response. Totally 8 infill walls with different materials and

systems have been tested (Table 1).

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Table 1. Tested frames

Label Infill

Material Plaster Developed System

BF - x -

B Brick x -

A AAC x -

LBP Locking Brick Dry bed joints

BP Brick -

BSP Brick Bilateral steel mesh

AFP AAC Fiber reinforced plaster

Infill-tieC Brick x Continuous horizontal steel plates

Infill-tieS Brick x Stepped horizontal steel plates

2.1 Material Properties

Experimental characterization of the materials (concrete, reinforcing steel, mortar, bricks, etc.) and

masonry wall prisms have been conducted. Due to scaling process 185x100x95 mm size perforated clay

bricks, 225x115x155 mm size clay bricks with locking ends and 125x100x300 mm size aac blocks were

produced to be used as infill material. Extensive testing of brick units, masonry prisms, mortar and

reinforcing steel was conducted. Results are tabulated in Table 2 below:

Table 2. Average mechanical properties of materials and wall prisms

Material

Compressive

Strength

(MPa)

Yield

Stress

(MPa)

Tensile

Strength

(MPa)

Young’s

Modulus

(GPa)

Shear

Strength

(MPa)

Shear

Modulus

(GPa)

Brick 3.7

9.7 (H)

- - - - -

AAC 2.9 - - - - -

Mortar & Plaster 4.0 - 1.0* 4.2 -

AAC Mortar 8.4 - 3.3* - - -

AAC Plaster 1.0 - 0.6* - - -

Concrete 28.6 - 2.5** 26.5 - -

Longitudinal Steel - 416 559 194 - -

Transverse Steel - 448 504 203 - -

Brick Prism 1.09 - - 2.3 0.15*** 0.8

Brick Prism + Plaster 1.04 - - 2.0 0.33*** 1.4

AAC Prism - - - - 0.27*** - *flexural tensile strength **split tension strength ***diagonal compression strength

Material tests were conducted using servo controlled MTS testing machine. Compressometers,

extensometers and strain gages were used for displacement and strain readings during tests. Masonry

prism tests were conducted using a displacement controlled test setup equipped with an electric motor

supplied screw jack. LVDT’s were used for displacement readings. Relevant ASTM standards were

followed for all tests. Compressive strength of wall prism, concrete, mortar, bricks flexural strength of

mortar, tensile strength of rebars, shear strength of brick mortar interface has been identified (Figure 3).

5

Figure 3. Testing of materials and units

2.2 Innovative Infill Systems

Due to the mechanical properties of its components, infill walls are brittle in nature. Compression

diagonal of the infill panel reaches its peak resistance at the early stages of lateral drift. After peak load

is reached contribution of the infill panel diminishes quickly and infilled frame response converges to

the bare frame. Recent studies to enhance infilled frame response focuses on:

(1) Formation of artificial horizontal slip layers at certain bed joints to prevent brittle failures and

force infill panel fail in a slip mode which is more ductile (Mısır 2014)

(2) Formation of vertical slip layers to provide slenderness to infill panel resulting in a rocking

mode which is more stable and ductile (Taşlıgedik 2014)

(3) Use of mesh reinforcement or geotextiles to increase ductility and stability (Calvi et al. 2004)

(4) Isolation of wall with bounding frame by means of gaps or devices (Memari and Aliaari 2004)

In this study mainly three structural systems are proposed aiming feasible, effective and affordable

solution to enhance infilled frame response. First suggestion is fiber or steel mesh reinforcement of aac

and brick infilled walls respectively. Second suggestion is use of steel tie members along bed joints

which are attached to closed U shape steel profiles anchored to columns. Third suggestion is the use of

locking bricks without mortar at bed joints.

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2.2.1 Bilateral Mesh Reinforcement

The proposed system is developed for clay brick masonry and comprises bilateral exterior reinforcing

of infill walls with a light mesh reinforcement without connection to the bounding frame and application

of regular plaster over the mesh for protection against corrosion (Figure 4). Light steel meshes with with

25 mm nominal pitch and 2 mm wire diameter are connected to each other on both sides of the wall via

tie wires passing through the holes drilled at various points on the wall. Tie wires are tightened with

nippers to ensure confinement of the infill wall between meshes. Composite action of the wall with steel

meshes enhance infill wall performance under IP and OOP loading.

Figure 4. Bilateral mesh reinforcement

The main goal of the proposed system is to increase flexural and shear strength of the masonry enclosure

under in-plane and out-of-plane loadings as well as damage control under IP loading by means of

minimizing cracking of the wall and sustaining integrity under high level of drifts.

2.2.2 Fiber Reinforced Plaster

Similar to bilateral mesh reinforcement, fiber reinforcement of plaster is proposed for infilled frames

constructed with aac units. A fiberglass mesh with 4 mm nominal pitch and 160gr/m2 density is utilized

for this purpose (Figure 5). 10 mm thick light plaster is applied over the mesh with compressive strength

of 1 MPa afterwards.

Figure 5. Fiber mesh reinforced plaster

The aim of fiber reinforcement is prevention of early cracking of the aac panel which is very sensitive

to lateral drift. Damage control and sustaining unity at large lateral drifts is another reason for

application.

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2.2.3 Horizontal Steel Plate (Infill-tie)

One other solution to enhance seismic performance of clay brick infilled RC frame is to provide an

easily installed connection between the masonry infill and the bounding frame so that sliding type of

failure at in-plane direction is achieved and the falling out of the masonry under out-of-plane

accelerations are prevented. This is accomplished through a simple slotted metal connector shaped like

a dog bone that is connected to a U shaped steel profile fixed to column face with dowels (Figure 6).

The connection only works in the horizontal direction and enables free movement in the vertical

direction, which allows flexibility during construction of the wall. The name given to this system is

Infill-tie (Gülkan et al. 2015).

Figure 6. Horizontal steel plate

Two different configurations for this masonry enclosure system is proposed. Infill-tieC composed of

horizontal slotted steel ties, placed at bed joints in every 3 courses of masonry unit and connected at

both ends to the closed U shaped profiles attached to columns. Whereas in infill-tieS configuration, ties

were attached at only one face and staggered in vertical direction for easier installation.

2.2.4 Dry Horizontal Joints (Locking Brick)

The construction process of this system begins with placing first layer end bricks at the bottom of the

wall. Remaining layers are laid with typical w class isolation bricks rotated 90 degrees in the OOP

direction of the frame. General purpose mortar is applied at head joint of the bricks whereas at bed joint

level bricks are interlocking and remained dry (Figure 7). After laying last layer of bricks gap between

the beam and the wall is filled with mortar to ensure arching mechanism under out-of-plane actions.

Wall construction is finished after plaster is applied at both sides of the wall.

Figure 7. Locking brick

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3. EXPERIMENTAL SETUP

In-plane seismic action is idealized by displacement reversals imposed by means of a 25-ton capacity

servo-controlled hydraulic actuator located in horizontal direction. Both ends of the actuator is pin

connected; one to the reaction wall and the other to the beam-column joint. Since single hydraulic

actuator is used in push and pull, four 45mm rods are used to connect rigid plates located at both ends

of the concrete beam to permit application of the cyclic reversed in-plane loading. Two 30-ton capacity

manually controlled actuators placed vertically on the beam-column joint to idealize gravity loads on

the columns. Before lateral loading, axial load ratio of columns is arranged to 0.175 depending on the

concrete compressive strength of the tested frame and kept constant throughout the test. Additional steel

weight blocks are placed over the beam to idealize slab loading equal to 10.25 kN/m. Sliding and tilting

of the lower beam is prevented by 12 post tensioned rods connecting test frame to the strong floor. The

out-of-plane movement of the test frame is also restrained by putting two horizontal rollers at each side

of the upper concrete beam (Figure 8). Two cycles of 0.35, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5 and 4.0%

lateral drifts are applied as loading protocol.

Figure 8. Test setup at METU Structural Mechanics Lab

The instrumentation setup is designed to measure applied loads, lateral drift, local deformations and

strains (Figure 9). Lateral load on frame and vertical loads on columns are measured by 3 load cells

attached to actuators. 12 strain gages attached to longitudinal reinforcements at the ends of columns and

beams are utilized to identify yielding sequence of RC members. 32 linear variable displacement

transducers (LVDT) are placed to track member end rotations, diagonal strut displacements, joint shear

displacements, lateral displacement of the frame and possible slip or uplifting of lower beam.

Figure 9. Instrumentation of test frames: LVDT’s (orange), strain gages (green), load cells (blue)

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4. EXPERIMENTAL RESULTS

4.1 Hysteretic Behavior

Considering nearly 50 channels tracked for each experiment, great amount of data is available to make

comparison among tested frames. However, due to limited space only hysteresis curves which best

describes structural of RC frames under seismic actions are illustrated (Figure 10). Compared with the

traditional infill walls, proposed techniques increases energy dissipation capacity of the RC frame under

increasing in-plane displacement reversals. For further information about results, please refer to Demirel

et al. 2016 and Demirel et al. 2017.

Figure 10. Hysteresis curves for tested specimens

4.2 Performance Limit States

With regard to capacity curves and damage development of enclosures, a correlation between design

performance levels and the reached in-plane drift levels might be defined. According to EN 1996-1-1,

2005), three performance limit states can be defined: The Operational Limit State (OLS), the Damage

Limit State (DLS) and the Ultimate Limit State (ULS). Additionally, a fourth performance limit state,

namely near collapse limit state (NCLS), is suggested to describe the performance of infilled frames.

Initiation of infill damage by means of detachment of panel with bounding frame and very light cracking

in the masonry panel in the bed and/or in the head joints is defined as OLS. DLS is considered as

repairable damage. Formation of diagonal cracking, sliding in the bed joints and very limited crushing

and spalling of plaster can take place. Ultimate limit state indicates severe damage. Reparability is not

economical. Crushing and spalling of mortar and brick units are more widespread however size of falling

units do not pose risk to human life. At the ULS, the maximum base shear capacity is generally reached.

NCLS is reached when infill damage is extensive to the extent that panel is close to collapse.

Contribution of panel to lateral strength and stiffness is very limited for this limit state. Falling parts

might risk the human life and possibility of out of plane failure of under out of plane actions is high.

-200-160-120

-80-40

04080

120160200

-5% -4% -3% -2% -1% 0% 1% 2% 3% 4% 5%

Late

ral L

oad

(kN

)

Drift

BF-200-160-120

-80-40

04080

120160200

-5% -4% -3% -2% -1% 0% 1% 2% 3% 4% 5%

Late

ral L

oad

(kN

)

Drift

B

-200-160-120

-80-40

04080

120160200

-5% -4% -3% -2% -1% 0% 1% 2% 3% 4% 5%

Late

ral L

oad

(kN

)

Drift

BP-200-160-120

-80-40

04080

120160200

-5% -4% -3% -2% -1% 0% 1% 2% 3% 4% 5%

Late

ral L

oad

(kN

)

Drift

BSP

-200-160-120

-80-40

04080

120160200

-5% -4% -3% -2% -1% 0% 1% 2% 3% 4% 5%

Late

ral L

oad

(kN

)

Drift

Infill-tieC-200-160-120

-80-40

04080

120160200

-5% -4% -3% -2% -1% 0% 1% 2% 3% 4% 5%

Late

ral L

oad

(kN

)

Drift

Infill-tieS

-200-160-120

-80-40

04080

120160200

-5% -4% -3% -2% -1% 0% 1% 2% 3% 4% 5%

Late

ral L

oad

(kN

)

Drift

A

-200-160-120

-80-40

04080

120160200

-5% -4% -3% -2% -1% 0% 1% 2% 3% 4% 5%

Late

ral L

oad

(kN

)

Drift

AFP

-200-160-120

-80-40

04080

120160200

-5% -4% -3% -2% -1% 0% 1% 2% 3% 4% 5%

Late

ral L

oad

(kN

)

Drift

LB

10

First major change in initial stiffness of load-displacement curve of infilled frames is identified as OLS.

In the light of aforementioned description of limit states, DLS, ULS and NCLS of the tested frames is

determined with regards to visual infill damage during tests (Figure 11). Additionally, considering force

displacement curves of the tested systems, a structural damage might be defined. DLS could be defined

around the peak force and ULS could be selected at a drift corresponding to 20% degradation after the

peak. Final performance limit states for DLS and ULS are determined regarding both structural and

visual damage considerations (Table 3). In order to define final performance state, weighted average of

structural and visual damage is calculated and rounded to nearest 0.25 according to formulas below.

𝐷𝐿𝑆𝑓𝑖𝑛𝑎𝑙 = 0.25 × 𝐷𝐿𝑆𝑣𝑖𝑠𝑢𝑎𝑙 + 0.75 × 𝐷𝐿𝑆𝑠𝑡𝑟𝑢𝑐𝑡𝑢𝑟𝑎𝑙

𝑈𝐿𝑆𝑓𝑖𝑛𝑎𝑙 = 0.40 × 𝑈𝐿𝑆𝑣𝑖𝑠𝑢𝑎𝑙 + 0.60 × 𝑈𝐿𝑆𝑠𝑡𝑟𝑢𝑐𝑡𝑢𝑟𝑎𝑙

The reason for lower contribution of visual damage with respect to structural damage in the

determination of final performance limit state is its subjectivity. Likewise, reason for higher contribution

of visual damage to final damage in case of ULS is better identification of visual damage for increased

drift levels corresponding to ULS.

Table 3. Performance limit states for tested infilled frames

Frame Id

Performance Limit States

OLS DLS ULS

NCLS visual structural final visual structural final

B 0.07% 1.0% 1.0% 1.0% 1.5% 2.2% 2.0% 2.5%

A 0.1% 0.5% 2.0% 1.5% 1.0% 3.0% 2.25% 2.5%

BP 0.08% 1.0% 0.5% 0.75% 1.5% 2.0% 1.75% 3.0%

LBP 0.10% 0.5% 0.5% 0.5% 1.5% 2.6% 2.0% 2.5%

BSP 0.10% 2.5% 0.5% 1.0% 4.0% 1.5% 2.5% N.A.

AFP 0.04% 2.5% 1.0% 1.5% 4.0% 2.0% 3.0% N.A.

Infill-tieC 0.08% 1.0% 1.0% 1.0% 2.0% 2.7% 2.25% 3.0%

Infill-tieS 0.06% 1.0% 1.0% 1.0% 2.0% 3.4% 2.5% 3.5%

5. CONCLUSIONS

Test frame is a code designed, ductile frame having an aspect ratio of 0.57, axial load ratio of 0.175.

Light clay or aac brick masonry is used as infill material. Loading is applied only in-plane direction.

Under these circumstances following conclusions might be drawn:

(1) Performance based inter-story drift limits for infilled RC frame system were proposed.

(2) Proposed systems show better performance as they are effective in improving energy dissipation

capacity of traditional infill walls.

(3) Proposed systems enhance structural performance by limiting damage under small lateral drifts

corresponding to service earthquakes and minimizing the probability of detachment and out-of-

plane collapse under large lateral drifts corresponding to design earthquake.

One significant limitation of this research is that infilled RC frame performances were determined

considering in-plane actions only. Mutual interaction of in-plane and out-of-plane infill damage should

be investigated for a better assessment of exact behavior.

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Performance Limit State

DLS ULS NCLS

B

A

BP

LB

P

BS

P

-

AF

P

-

Infi

llti

eC

Infi

llti

eS

Figure 11. Infill damage at performance limit states

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6. ACKNOWLEDGMENTS

This research work has been funded by the European Commission under the program “Research for the

benefit of SME Associations”, research project INSYSME “Innovative systems for the earthquake

resistant masonry enclosures in RC buildings”, grant FP7-SME-2013-2-GA606229, 2013-2016.

Valuable contribution and efforts of METU Civil Engineering Department Structural Mechanics

Laboratory workers Hasan Metin, Osman Keskin, Murat Demirel, Barış Esen and Salim Azak is

gratefully acknowledged by the authors.

7. REFERENCES

Bertero V and Brokken S (1983). Infills in seismic resistant building. Journal of Structural Engineering,

10.1061/(ASCE)0733-9445(1983)109:6(1337), 1337-1361.

Calvi G.M., Bolognini D. and Penna A. (2004). Seismic performance of masonry-infilled RC frames, benefits of

slight reinforcements. 6 Cong. Nac. de Sism. e Eng. Sism., Guimarães, Portugal.

Demirel IO, Yakut A, Binici B, (2016): An experimental study on in-plane seismic performance of infilled RC

frames. Proceedings of the 11th fib International PhD symposium in civil engineering, Tokyo, Japan.

Demirel IO, Yakut A, Binici B, (2017): Seismic behaviour of RC frames infilled with different techniques.

Proceedings of the 16th WCEE, Santiago, Chile.

Earthquake Engineering Research Center (EERC) (2011). 23 Ekim 2011 Mw 7.2 Van Depremi Sismik ve Yapısal

Hasara İlişkin Saha Gözlemleri. Report No: METU/EERC 2011-04, Middle East Technical University, Ankara,

Turkey (in Turkish).

Earthquake Engineering Research Center (EERC) (2012). 9 Kasım 2011 Mw 5.6 Van-Edremit Depremi Sismik

ve Yapısal Hasara İlişkin Saha Gözlemleri, Report No: METU/EERC- IMO 2012-01, Middle East Technical

University, Ankara, Turkey (in Turkish).

Gulkan P, Binici B, Sucuoğlu H, Taghipour A, Demirel IO, Tanışer S, Güneş O, İsmail M, Fehling E, Nakano Y,

Sanada Y, Choi H (2015). An Innovative tie system for improving the monolithic behavior of masonry infilled

reinforced concrete frames (INFILTIE). 3rd Turkish National Conference on Earthquake Engineering and

Seismology, İzmir, Turkey.

Langenbach R (1987). Masonry as a ductile material: Traditional and contemporary construction practices utilizing

unreinforced masonry in seismic areas. Proc., The Masonry Society, University of California, Los Angeles, USA.

Mehrabi, A., Benson, S., Schuller, M., Noland, N. (1996). Experimental Evaluation of Masonry-Infilled RC

Frames. Journal of Earthquake Engineering 122(3), 228–237.

Memari, M., Aliaari, M. (2004). Seismic Isolation of Masonry Infill Walls. Proceedings of the 2004 Structures

Congress. Nashville, Tennessee; USA

Misir, I. (2014). Potential Use of Locked Brick Infill Walls to Decrease Soft-Story Formation in Frame Buildings.

Journal of Performance of Constructed Facilities 29(5)

Negro, P., Verzeletti, G. (1996). Effect of Infills on the Global Behaviour of R/C Frames: Energy Considerations

fromPseudodynamic Tests.” Earthquake Eng. and Structural Dynamics 25, 753-773

Nicola, T., Leandro, C., Guido, C., Enrico, S. (2015). Masonry Infilled Frame Structures: State-of-the-art Review

of Numerical Modelling.” Earthquakes and Structures 8(1).

Polyakov, S.V. (1956). On the interaction between masonry filler walls and enclosing frame when loaded in the

plane on the wall, Translations in Earthquake Engineering, Research Institute, Moscow.

Rodriguez H, Varum H, Costa A (2008). Simplified macro-model for infill masonry panels. Journal of Earthquake

Engineering, 14 (3), 390-416.

Sucuoglu, H. (2013). Implications of masonry infill and partition damage in performance perception in residential

buildings after a moderate earthquake. Earthquake Spectra: May 2013, Vol. 29, No. 2, pp. 661-667.

Tasligedik, Ali Sahin. (2014). Damage Mitigation Strategies for Non-structural Infill Walls. PhD diss. University

of Canterbury