COMPARING DESIGN TECHNIQUES FOR
EARTHQUAKE LOADING ON BRIDGES USINGJAPANESE METHOD AND PAPUA NEW GUINEAMETHOD
Gilbert Kapi∗
MEE12615

Supervisor: Jun-ichi HOSHIKUMA ∗∗Toshihide KASHIMA ∗∗∗Yoshinori UCHIUMI ∗∗∗∗ABSTRACT

A comparison of some aspect of Japanese and the Papua New Guinea (PNG) method for determining
seismic loading on Bridges was done. The areas looked at include a review of the history of thedevelopment of the Japanese Seismic Code based on lessons learned from the past large earthquakes
including the 1923, Great Kanto Earthquake, the 1964 Niigata Earthquake, the 1978 Miyagi-ken Oki, the1995 Hyogo-ken Nanbu Earthquake and the 2011 Great East Japan Earthquake. The study also involved
comparing the standard acceleration response spectra for both countries based on the 1985 PNG Code andthe 1996, 2002 and 2012 version of the Japanese code and the evaluation of an existing Bridge Pier in
PNG using the Japanese Method. A very brief comparison was also done on seismic restrainers used in
Bridges in PNG and the reinforcement detailing near the plastic hinge zone of the circular column used in
the bridge pier and the section details was also compared with the detailing arrangement as specified in
the English version of the 2002 Japanese Design Specification of Highway Bridges Part V. Seismic
Design. The findings which include (1) basic standard acceleration spectrum for seismic design in PNG
was only suitable for normal earthquakes whilst the Japan Code allows for both normal earthquakes aswell as larger scale earthquakes (2) difference in steel reinforcement arrangements for circular sections (3)termination of starter reinforcement bars for the pier columns in the bridge evaluated being located in theplastic hinge zone (4) sufficient strength, displacement and ductility capacity in the bridge pier designed
according to PNG code were then presented in the report.
Keywords: Bridge, Seismic Loading, Reinforcement Details, Pier Columns.
1.INTRODUCTIONPNG is seismically active with the Pacific plate and the Indo Australian Plate colliding with each otherand three smaller tectonic plates in the middle also colliding with each other and also colliding with themajor tectonic plates. The top 10 major earthquakes range from Mw 7.6 to Mw 8.1. Therefore the studyof earthquake engineering and consideration for earthquake loading on building and bridge structures isimportant in PNG. In this study, comparison was made on some aspect of the both design codes with∗

Department of Works (Operations Division), Papua New Guinea.
Chief Researcher at the Centre for Advance Engineering Structural Assessment and Research, Public Works
Research Institute, Tsukuba Japan.
∗∗∗Senior Researcher at Building Research Institute, Tsukuba, Japan.
∗∗∗∗MSc. Senior Engineer at Chodai Co.,Ltd, Consulting Engineers & Planners, Tsukuba Office, Japan.
∗∗1more focus on the standard acceleration response spectrum and the evaluation of an existing pier in abridge in PNG using the Japanese method for strength, displacement capacity and ductility capacity. Thestudy also briefly looked at the PNG code, ‘Earthquake Engineering for Bridges in PNG’, which have 3
short chapters and 8 appendix and when compared to the Japanese code, the PNG code only caters forsmaller earthquakes. A brief discussion on the seismic restrainers specified in the PNG code and theseismic detailing of reinforcement the circular column section and the termination of the starter bars andthe location of the plastic hinge was also discussed and comparison was done against the Japanese code.
2.DATAThe data used in this study was from the seismic code from both Japan and PNG and the DesignDrawings for Warangoi River Bridge. The properties of concrete and steel used in the calculations arebriefly presented below in Table 1 and Figure 1;
Table 1 –Properties of Concrete and Steel Reinforcing Bars used in the Evaluation(1) Concrete(2) Steel Reinforcing Bars

Design Compressive

f ’c25MPaEc

2.53x104MPa

Yield Strength

fy500MPa

Yield Point of Confining

σsy345MPaEs

2.0 x 105MPa

Strength
Young’s Modulus

Reinforcement
Young’s Modulus

Stress-strain relations
Shown below in Figure 1 are the stress strain curves adapted for the concrete and steel reinforcement bar
used for the pier column considering the circular concrete column is not confined. The maximum strain ofconcrete is 0.0035. A bilinear model was adapted for steel reinforcing bars as shown in Figure 1(2) below
and other strength properties of concrete and steel reinforcing bars are shown in Table 1 above.
(1) Concrete(2) Reinforcing bar

0.85σckEs2

σsy
Esεsy0.002 0.0035

Figure 1(1) and 1(2) Stress Strain Curves used for Calculation Strength Displacement and Ductility
Capacity of the Pier.

2Structural Model Used.
The structural model adapted for analysis in line with the guidelines from the Japanese code is show inFigure 2 below. In this model the structure is fixed at the pier in the middle andFigure 2 – Analysis Model Adapted Assuming Loading in the Bridge Axis Direction andSupport Condition adapted.
The standard acceleration design spectrum for determining seismic coefficient in PNG Codeis not shown here due to space limitation but presented in Figure 3 below are standardacceleration spectrum from the Japanese code used to check the pier for its adequacy forlarge scale earthquakes.

Figure 3 –Standard Acceleration Response Spectrum for 2002 and 2012 used in Evaluation of the Bridge
Pier in this Study3

3. THEORY AND METHODOLOGY
Loading on Bridges consist of primary loads and secondary loads. The Primary Loads consist of Deadload (D), Prestressed Force(PS), Effects of Creep of Concrete(CR),Effect of Drying Shrinkage of concrete(SH),Earth Pressure(E),Hydraulic Pressure(HP),Buoyancy or Uplift(U)Earthquake loading is considered as a secondary load.
In this case the only the horizontal load seismic loading is considered based on the fact that it is highly
unlikely for combination of above primary loading and the seismic loading to occurred at the same time.
The seismic loading is calculated is taken as the mass of the superstructure multiplied by the accelerationinduced into the structure due to earthquake and the formulae specified in the PNG and the Japan Codes
were used as follows;
SI = CzCDS10 …………………………………………………………………………………………..(3)SII = CzCDSII0…………………………………………………………………………………………..(4)where SI is the Type I acceleration response spectra, SII is the Type II acceleration response spectra, Cz is
the zone modification fact, CD is the damping factor for damping ratio, S10 is the Type I-Standard
Acceleration Response spectra and S110 is the Type II standard response acceleration response spectra
V =C*I*M*Wt ………………………………………………………………………………………..(5)Where V is the total design base shear force in the direction being considered, C is the basic shear
coefficient for the appropriate zone, period and site condition, I is the importance factor, M is the materialfactor, Wt is the total weight of the structure subject to the seismic acceleration, taken as the dead load
plus the super imposed dead load.
The method or procedure followed in thisevaluation was to create the mode based on thestructural drawing of the existing bridge structureand do a linear static analysis and a nonlinear
static analysis using the existing pier dimensions
and evaluate seismic adequacy.
The column sections were than revised and anonlinear analysis was again carried out todetermine the adequacy for large scale
earthquakes.
The results of load deformation and moment
rotation relationships were obtained and used incalculating the strength, the deformation and theductility of the column using the Japanese method
as specified in the Japan Seismic Code for Bridges
2002 English version.
Figure 4 Flow Diagram Showing the procedure used in theevaluation of the pier4

4. RESULTS AND DISCUSSION
4.1. Loading Deformation Chart.
Figure 5 on the left shows theloadanddeformation
relationship obtained using the‘non pier’ which is a nonlinearanalysis software developed by
Chodai Company of Japan toanalysis piers. The result below
shows the case where theconfinement effect of the hoop
reinforcement
wasnotconsidered. A similar analysis
was also done which include
confinement effect of the hoop
reinforcement placed at 75mm
spacing along the pier column.
The results with the confinement
effect consideration indicate
better results and confirms thatpier to have sufficient strengthand deformation capacity as
shown in brackets in Table 2
Figure 6 – Load Deformation Chart for both 1.25 Diametre single anddouble reinforcement and 1.4m diameter double reinforcement
Table 2. Results for Evaluations of Strength and Deformation of Warangoi Bridge Pier

Description

Single, D =1.25m

Double, D =1.25m

Double D =1.4m

Maximum Deformationfrom Non LinearAnalysis
Maximum Load fromNon Linear Analysis, Pu

114 mm(251 mm)

102 mm(262mm)

96 mm(206mm)641kN(657.5kN)

1046kN(1138.3kN)

1263kN(1359kN)

Calculated Deformation,
δeUltimate Capacity, Pa

94mm(148mm)1162.41kN(1825.9kN)

93.5mm(170mm)1503.2kN(2685.4kN)

84mm(135mm)2000kN(3175kN)

Notes: Single in the table above means single layer of reinforcing bar arrangement and double means
double layer of reinforcing bars arrangement and D, is the diameter of the pier column.
There original columns were designed using the PNG code and the evaluation was done using theJapanese Code 2002 English version but also used the 2012 standard acceleration spectrum for three caseas shown in Table 25

5.CONCLUSIONSIn this study a comparison was done on the history and development of seismic design for bridges inJapan and PNG and the lessons learned for damages to bridge structures due to large earthquakes. A casestudy was also carried on an existing bridge pier which consists of two 1.25m diameter columns of
5.876m and supported at the base by a pile capping and connected at the top by a column cap which
supports the superstructure as shown in Figure 2. The pier was evaluated for strength, deformation andductility capacity in the longitudinal direction. The results obtained indicated that the revised column
section with the increased diameter from 1.25m to 1.4m with double layers of main reinforcement andhoop spacing of 75mm would meet the requirements of the large and rare inter-plate earthquakes without
consideration for confinement effect.
However the existing 1.25m diameter columns of the existing pier columns with single
reinforcement and with consideration of confinement effect due to the shear reinforcement spaced at75mm was found to be adequate to withstand the strong ground acceleration such as the Great East Japan
Earthquake.
The only weakness found in the column was the termination of the starter reinforcing bars very
close to the plastic hinge region.
6.RECOMMENDATIONIn this study, it is recommended that special considerations should be given in making sure proper
detailing of the reinforcement and also detailing of seismic restraining devised to prevent undesirable
failures such as pulling out of reinforcement due to insufficient development length.
Inclusion of Level 2 or strong ground acceleration spectrum in the code based on recorded strong
ground motion is also recommended for the PNG Code.
7. ACKNOWLEDGEMENTS
My special acknowledgement to Supervisor Dr.Junichi Hoshikuma-Chief Researcher at the Public Works
Researcher Institute of Japan in Tsukuba and my Advisor Dr. Toshihide Kashima –Senior Researcher atIISEE and Yoshinori Uchiumi, and Senior Engineer, Xinyu Li, Engineer and the staff of the Design andEngineering Section-International Division of Chodai Company Limited of Japan, Tsukuba office, fortheir warm reception and assistance during the one week attachment with Chodai as part of this study.
8. REFERENCES
Earthquake Engineering for Bridges in Papua New Guinea, Department of Works 1985
Bridge Design Brief, Department of Works 1990.
Hollings J.P. 1971, “A Report for Earthquake Engineering for Bridges in the Territory if Papua NewGuinea”.
Hoshikuma, Jun-ichi, Power Point Presentation on Japan History of Design Specification of Bridges andBridge Damage Pattern, Chief Researcher of Centre for Advanced Engineering Structural Assessment andResearch (CAESAR) –Public Works Research Institute.
Junichi Sakai, Junichi Hoshikuma and Shojiro Kataoka, Revision of Japanese Seismic Design
Specifications for Highway Bridges Based on Knowledge Derived from Recent Earthquakes andResearch Accomplishment, 7th National Seismic Conference on Bridges & Highways, Paper No.118,Oakland, CA, USA, 2013.5.
Specification for Highway Bridges –Part V Seismic Design, Japan Road Association March 2002

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