Citation: Hamidon, N.Z., T. Kabeyasawa (2023), Seismic performance of precast reinforced concrete
Beam-to-column connection, Synopsis of IISEE-GRIPS Master's Thesis.

SEISMIC PERFORMANCE OF PRECAST
REINFORCED CONCRETE BEAM-TO-COLUMNCONNECTION
Nurul Zawani binti HAMIDON1
MEE22708

Supervisor:Toshikazu KABEYASAWA2

ABSTRACTThis research aims to analyze the behavior of precast structures in Malaysia when subjected to seismic
activity, specifically focusing on the connection between beams and columns. To achieve this, a newmethod called the Beam-Line Method (BLM) has been developed and utilized to model and analyze theseismic performance of these connections in precast frames. The study employs non-linear static
pushover analysis and non-linear dynamic time history analysis to comprehensively evaluate thestructural response under seismic loads. Additionally, the seismic performance of the building isassessed by combining the seismic capacity curve obtained through pushover analysis with the elastic
response spectrum curve of the earthquake. Furthermore, the study investigates the significance ofconnections in the overall structural performance by calculating moment rotations in the beam-tocolumn connection. These are then utilized in the seismic analysis of the entire frame. The outcomes ofthis research provide valuable insights into the seismic behavior of precast reinforced concrete beamto-column connections, thus informing future design and construction practices to enhance the seismic
resilience of such structures.
Keywords: Seismic Response, Precast Structures, Beam-to-Column
MethodConnection,

Beam-Line

1. INTRODUCTION
Malaysia's rapid urbanization and construction development have ushered in an era of increased
utilization of precast reinforced concrete (PRC) due to its multiple benefits. These advantages include
enhanced speed, efficiency, cost-effectiveness, quality control, and the reduction of on-site errors andwaste. The government's focus on regulating and promoting this technology through the Construction
Industry Development Board (CIDB) has further augmented its growth. From 2015 to 2020, there has
been a significant rise in the adoption of the precast technique in public projects in Malaysia, soaring
from 24% to 85.3%. The trend toward hybridization, combining traditional methods with moderntechnology, has emerged as an optimal solution, with joint guidelines developed by the government andacademics. However, Malaysia's geographical location near the Pacific Ring of Fire introduces severe
seismic considerations. The region has been the center of catastrophic earthquakes, including thedevastating 2004 Indian Ocean earthquake and other significant seismic events in surrounding areas likeThailand and the Philippines. This study explores the seismic performance of PRC beam-to-column
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Public Work Department, Malaysia.
Associate Professor, Tokyo Metropolitan University.

1connections, a critical aspect of construction in a seismically active region. Through a thoroughexamination of recent trends, the implementation of the PRC, and an analysis of the seismic activities
around Malaysia, the study aims to provide a comprehensive understanding of how the PRC can beutilized effectively and safely in an area prone to earthquakes. Therefore, the research aims to analyze
the moment resistance of the proposed precast beam-to-column connection using the beam-line method,along with obtaining the load-deformation curve from non-linear analyses. The study seeks to enhanceconstruction practices and seismic safety in Malaysia's rapidly expanding precast industry by exploringthese areas.
2. TARGET BUILDING
Malaysia’s Public Works Department (PWD) has developed a catalog of pre-approved plan (PAP)
buildings to streamline the design process for various ministries. Among over 100 buildings, the Clinic
Type 3 building, a popular choice across Malaysia, is prominently featured. However, most of these
PAP structures, including the Clinic Type 3 building, were designed based on the non-seismic code EN
1992, without considering seismic load requirements. This is a significant concern, particularly inregions prone to earthquakes like Sabah state. The study focuses on the base shear coefficient, a key
seismic design parameter, and reveals that a coefficient of 0.44 implies a seismic force constituting 44%of the structure's total weight. Such a significant force highlights the urgent need to address seismic
considerations in the design of PAP buildings. Detailed calculations and understanding of the seismic
factors emphasize the necessity to adapt design standards to ensure structural safety in earthquake-prone
regions. Figure 1 shows one of the precast connection details that has been used for this study.
The Clinic Type 3 buildingin Malaysia was designed following
EC2 for gravity load and EC8 with
Malaysia National Annex forearthquakeload.
Key
designparameters included a peak groundacceleration of 0.16g, medium
ductility class (DCM), an essentialbuilding factor (γ1) of 1.5, and groundtype E with over 30m deep sediment tobedrock. These specifications reflect
the building's vital function as a clinicandtheneedfor
seismic
considerations. Table 1 shows the baseshear force value that has beenobtained for this target building.
Figure 1. Details of the connection were located at 3/G
at 2F story or X8/Y7 referring to the CANNY model.
All measurements are in millimeters.
Story

Table 1. Story lateral force calculation for the target building
Height, Zi (m) Mass, mi (kN)
Zi.mi (kNm)
Zi.mi / ΣZi.mi

Fi (kN)RF

11.85

5501.1865189.02

0.174

5416.103F

9.30

15522.93

144363.22

0.386

11994.13

2F

4.80

34287.55

164580.23

0.44013673.82

GF034486.72

00.0000Total ΣZi.mi:374132.47

1.00

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3. METHODOLOGY
In this study, the strength of the entire connection of the target building has been evaluated using twomethods. The first method employed is the Architectural Institute of Japan (AIJ) method, which isconsidered the conventional approach for the AIJ model. Equation 1 outlines the moment resistance for
AIJ method. On the other hand, for the precast method, the Beam-line method (BLM) has been applied
to the BLM model. The equation for this method is detailed in the book "Precast Concrete Structure" byKim S. Elliott, as indicated in equation 2 (K.S Elliott, 2016).
𝑀𝑅 = 0.9. 𝛼𝑡 . 𝛼𝑦 . 𝑑𝑀𝐸
𝐿 + (2 × 𝑙𝑃 )2.22 × 𝐸𝑐𝑚 × 𝐼𝑐𝑟 𝑙𝑒 −1= [()+() ( )]𝑀𝑅
𝐿
𝐴𝑠 × 𝐸𝑠 × 𝑑2
𝐿(1)
(2)

Furthermore, the flexural cracking moment was also determined as part of the analysis. The
cracking moment is an important parameter that indicates the onset of cracking in the structural elements.
The equation of the cracking moment, Mc can be referred to as equation 3 (Mukai, 2022);
Mc = 0.56(√σB ). ZE +ND
6(3)The Sugano formula calculates a structural element's stiffness degradation, αy. Stiffness
degradation is an important parameter in structural engineering as it helps understand how an element’sstiffness decreases under deformation. This is particularly important in seismic design. The formulaprovided is shown in equation 4 (Mukai, 2022):𝐸𝑠
𝑎𝑑 2
𝑝𝑡 + 0.043 + 0.33𝜂0 ) ( )𝐸𝑐𝐷𝐷(4)

Moment𝛼𝑦 = (0.043 + 1.64

Rotation angle
Figure 2. Member-end moment-rotation
relation from Japan Technical Standard
Manual for Building Structures

Figure3. Intersection of moment-rotationline with beam-line (Elliott et al., 2003)

Figure 2 illustrates the correlation between a structural member's bending moment and its rotation. The
curve is vital for comprehending beam behavior under bending loads and identifying connection types,
such as rigid, semi-rigid, or pinned. A notable observation from the graph is the stiffness degradation,
indicating a decline in beam stiffness with increasing deformation, represented by the stiffness
degradation ratio. In structural engineering, the choice of connection type is vital, especially inearthquake-prone regions where allowing rotation can help absorb ground movement energy. The
moment-rotation curve, coupled with the beam-line, as shown in Figure 3, helps determine two key
connection properties: the allowable moment capacity (ME) and the secant stiffness (SE).

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4. RESULTS AND DISCUSSION
3.1. Simulation Results of the Non-linear Static Pushover Analysis

Load Deformation CurveAIJ Model

Load Deformation Curve
Beam-line Model

Story Shear Coefficient

Story Shear Coefficient

Figures 4 and 5 depict the relationship between the base shear and story drift for the AIJ and BLM
models. The base shear refers to the total horizontal force a structure must withstand during anearthquake. The story drift refers to the displacement between two consecutive building floors. The baseshear coefficient of the frame at yielding is about 0.15 in AIJ model, and 0.12 in BLM model. This result
suggests the strength of the BLM model is smaller compared to AIJ model due to the failure of thecolumn-beam connections. The story drift concentrates on 2nd story in the AIJ model compared to theBLM model. The shear coefficient of the design seismic force is 0.44 in the rigid model, so that it
exceeded the yielding strength of the building. Both models have a near-similar threshold before failure.
Precast-designed buildings might fail sooner during seismic events compared to conventionallydesigned ones, with the latter showing higher ductility.

0.20
0.15
0.10
0.05

3F-RF
2F-3F
GF-2F

0.00
0.000

0.010
0.020
0.030
Interstory Drift Ratio (rad)Figure 4. Load-deformation curve for the AIJ
model obtained from the PA

0.20
0.15
0.10
0.05

3F-RF
2F-3F
GF-2F

0.00
0.000

0.010
0.020
0.030
Interstory Drift Ratio (rad)Figure 5. Load-deformation curve for the BLM
model obtained from the PA

Spectral Acceleration, Sa (cm/s2)

The seismic capacity curves obtained from the PA with the elastic response spectrum curveof the earthquake and the specific building must be compared to accurately determine the building’s
seismic performance. Regarding Figure 6, the spectral displacement decreases as the period increases
around the point of maximum response (cross point). It shows the AIJ and BLM models exhibit a similar
response in terms of deformation,
Capacity Spectrum
without significant differences. An
700
analysis of these graphs showed that thePush Over Analysis AIJ
AIJ model had a yield point of 8.6 cm,
600
Push Over Analysis BLM
while the BLM model had a yield point
Elcentro
500of 6.7 cm. Note that the yield point wasRanau
outside the earthquake ground motion
Capacity400
and response spectra range. The spectral
Curve
Perfomance
displacement values were determined as
300
Point
5.15 and 1.0 cm for El Centro and Ranau,
200
respectively. The primary objective of
Dy=8.6cm
identifying the seismic performance100
point was to observe the building’s
Dy=6.7cm
displacement during an earthquake. The005
1015 performance point or the target
displacement was then compared with
Spectral Displacement, Sd (cm)Figure 6. Comparison of the capacity spectra of the AIJ and the hinge formation to determine thebuilding’s state when the displacement
BLM models (earthquake).
was reached.

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3.2. Simulation Results of the Non-Linear Dynamic Time History Analysis

4000

2000

-0.00030-0.0001-2000

0.00010.0003
3F-RF
2F-3F
GF-2F

Story-shear force, Q (kN)

Story-shear Force, Q (kN)

The structure’s response to the El Centro and Ranau ground motions was meticulously analyzed using
the AIJ and BLM models. The results of these analyses are shown in Table 2. The load–deformationcurves of the AIJ (Figure 7) and BLM (Figure 8) models, specifically for the Ranau ground motion,
were included to comprehend the load–deformation behavior of the target building. Figures 9 and 10depict both models’ load–deformation curves under the El Centro ground motion.
4000

2000-0.0003

0-0.0001-2000

0.00010.00033F-RF
2F-3F
GF-2F-4000
Interstory Drift Ratio (rad)-4000
Interstory Drift Ratio (rad)Figure 7. Load–deformation curve for the AIJ
model under the Ranau ground motion.

Figure 8. Load–deformation curve for the BLM
model under the Ranau ground motion.
9000

6000
3000
0-0.002-0.0010-3000
-6000

0.001

0.002

3F-RF
2F-3F
GF-2F

Story-shear force, Q (kN)

Story-shear force, Q (kN)

9000

6000
3000
0-0.002-0.0010-3000
-6000

0.001

0.002

3F-RF
2F-3F
GF-2F

-9000
Interstory Drift Ratio (rad)-9000Interstory Drift Ratio (rad)Figure 10. Load–deformation curve for the BLM
model under the El Centro ground motion.

Figure 9. Load–deformation curve for the AIJ
model under the El Centro ground motion.

Table 2. Comparison of the maximum story drifts for the AIJ and BLM models with the THA
Maximum story drift of theMaximum story drift of theEarthquake
AIJ model
BLM model
El Centro

0.00120.0010Ranau

0.000240.00020

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5. CONCLUSIONS
From this study, the base shear coefficient for the target building was determined as 0.44 based on theEC8 seismic design. The base shear coefficient calculation depended on various behavior factors (e.g.,soil factor, building important factor, and natural period of the building). The target building was
designated with a medium-ductility class that has a specific rule for additional reinforcement, that is, thenumber of reinforcements must be higher than that of the low-ductility class. The number ofreinforcements impacts the building’s seismic performance differently, especially for the beam–columnconnections, regardless of method (i.e., conventional or precast).
The seismic capacity curves of the target building were established by using non-linear
static PA. The overall results showed that the maximum story drift for the BLM model was less thanthat for the AIJ model designed using the conventional method. In other words, under seismic events,
the building with the BLM model will undergo plastic hinge formation sooner than that with the AIJ
method. Referring to the base shear values for both methods, the AIJ and BLM models can be used toachieve similar displacements. However, the AIJ model showed stiffer values when compared to theBLM model due to the maximum story drift obtained from the PA. This was because the BLM modelexperienced deterioration.
The seismic performance point for the target buildings was achieved. The load under thetarget building is safe under 0.16 g PGA if the building is designed under the Type E ground condition.
This is because the maximum story drift for the El Centro ground motion was 0.0069 as the plastic
hinges were being formed beyond the O and IO states. Meanwhile, the maximum story drift for theRanau ground motion was 0.0013, in which the plastic hinges were formed before the O state.
The analysis of the THA results showed that the maximum story drifts of both the AIJ andBLM models under the El Centro and Ranau ground motions were very small and almost identical. Onlya slight difference, which was caused by the limitation in the calculation of Canny’s program for thedeteriorated BLM model, was found in the results for the El Centro ground motion. In the BLM model
analysis, the results could not be obtained when deterioration occurred. Therefore, the El Centro groundmotion intensity was reduced from 1.0 to 0.35 to obtain the results. These values depicted a 65% or 0.65
decrease in absolute terms. For the Ranau ground motion, the original intensity was already smaller than
the seismic resistance of the target building.
ACKNOWLEDGEMENTS
This research was conducted during the individual study period of the training course“Seismology, Earthquake Engineering and Tsunami Disaster Mitigation” by the Building ResearchInstitute, JICA, and GRIPS.I would like to express my sincere gratitude to my supervisor, Dr. Toshikazu
Kabeyasawa, for their invaluable guidance and unwavering support. Their insightful suggestions andencouraging words have significantly contributed to the accomplishment of this project. In the samelight, my advisor, Yuri Otsuka has my sincere appreciation. Their expert advice, thorough critique, andnurturing mentorship have been instrumental in my work and thought processes throughout the study.
REFERENCES
Architectural Institute of Japan (2001). Data for Structural Calculation of Reinforced
Concrete Building
K.S Elliott. (2016). Precast Concrete Structures 2nd Edition. CRC Press.
Mukai. (2022). Lecture notes on Reinforced Concrete 1.
Elliott, K. S., Davies, G., Ferreira, M., Halil, G., & Mahdi, A. A. (2003). Can Precast Concrete Structures
be Designed as Semi-Rigid Frames? Part 1: The Experimental Evidence. The Structural Engineer,81(16), 14-27.
Council Japan Association of Structural Engineers. (2015). Technical Standard Manual for Building
Structure.

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