8/10/2019 1-s2.0-S2211381911000245-main

1/5

Available online at www.sciencedirect.com

2211-3819 2011 Published by Elsevier B.V. Selection and/or peer-review under responsibility of the Organising Committee of The International

Conference of Risk and Engineering Management.

doi:10.1016/j.sepro.2011.08.023

Systems Engineering Procedia 1 (2011) 137141

2011 International Conference on Risk and Engineering Management (REM)

Experimental Research on Seismic Behavior of Unbonded Precast

Reinforced Concrete Frame

Jianqiang Hana,b,

*, Yulong Caic

, Changyan Lina

, Guanyu Gaoa, Fei Wang

a

a College of Civil And Architectural Engineering, Hebei United University, Tangshan 063009, ChinabEarthquake Engineering Rresearch Center of Hebei Province, Tangshan 063009, China

c

China Architecture Design & Research Group, Beijing, 100044, China

Abstract

Unbonded precast reinforced concrete frame is a new assembly architecture structure. This thesis studies deeply the crack

development characteristics, failure pattern, hysteresis curve and the displacement ductility of unbonded precast reinforced

concrete frame, by analyzing one unbonded precast reinforced concrete frame under low reversed cyclic load test. We build a

model using finite element analysis software to the test piece model analysis, the analysis result consistent with the experimental

results. Experimental studies indicate that assembly of prestressed reinforced concrete frame structure has a good seismic

performance. This unbonded precast reinforced concrete frame is a new kind of structural system complying with the

development of architectural engineering, which is useful in application in the earthquake area. 2011 Published by Elsevier Ltd.

Keywords: unbonded, precast, reinforced concrete, frame, structure engineering.

1. Introduction

The unbonded precast reinforced concrete frame is a new kind of structural system assembly, complying with the

development of architectural industrialization. This structural system is of various advantages---- less steel

consuming, lower self-weight, higher construction efficiency, better quality, lower labor consuming, energy saving,

more environment friendly and higher social and economic benefits, which are in favor of sustainable socialdevelopment. At present, this structure has been applied in various building constructions in Japan and the United

States[1-2], having shown its unique advantages. The researches in this area in China are mainly conducted in the

node specimen test[3-4], however, the overall framework of the prestressing force pilot studies are relatively rare.

Our project group fabricated frame of this new node specimens and has systematically studied it[5-7], obtaining the

seismic performance of this new structural system. This paper is based on the test of the overall effect of the cyclic

loading on a two floors of a two-span prestressed frames fabricated with reinforced concrete frame, researching its

overall structure seismic performances---- the prefabricated crack case, failure mode, ductility, energy dissipation,

* Jianqiang Han. Tel.: 15032587758; fax: 0315-2592180.

E-mail address: tshjq@139.com.

2011 Published by Elsevier B.V. Selection and/or peer-review under responsibility of the Organising Committee of The International Conference

of Risk and Engineering Management.

8/10/2019 1-s2.0-S2211381911000245-main

2/5

138 Jianqiang Han et al. / Systems Engineering Procedia 1 (2011) 137141

and stiffness degradation of the new system.

2. Experimental Design

2.1. Specimen design and loading device

Test specimen is fabricated with two floors and two spans of prestressed reinforced concrete frame structure. The

concrete grade of frame basis is C30. The concrete grade of columns and beams is C50. The channels for Strand

were reserved in the framework of prefabricated columns and beams. When the prefabricated components meet the

required strength, we fabricate the frame with three steps. The first step is hoisting the prefabricated components.

The second step is perfusing the beam end node joints with high strength mortar. And the final step is tensioning

strand. To ensure that the concrete beam end assembly-node bound has better strength in fabricated frame beam

ends, we paste two layers CFRP over the range of the beam ends. Precast concrete specimen reinforced concrete

frame design dimensions, reinforcement and the loading device are shown in Fig. 1.

Fig. 1. Specimen dimensions

Framework model of the reinforcement ratio of ordinary steel, hoop, the volume of hoop and stirrup values are

shown in table 1.

Table 1. Component reinforcement characteristic values

Sample site Size Reinforcement ratio Hoop Volume of hoop Stirrup value

Column 200200 2.83% - 1.4% 0.08

beam 100200 1.54% 1.13% - -

2.2. Loading program

Unbonded precast reinforced concrete frame specimen was loaded by load-displacement hybrid control

method[8]. When the final bearing capacity of the specimen decreases to about 85% of the ultimate load , the

specimen is regarded as damaged and the teat terminates. Test measurements included the control section main bar

strain, crack and corner nodes, and the overall displacement of the framework. Loading program is shown in Fig. 2.

8/10/2019 1-s2.0-S2211381911000245-main

3/5

Jianqiang Han et al. / Systems Engineering Procedia 1 (2011) 137141 139

Fig. 2. Specimen dimensions

3. Test results and analysis

3.1. Failure mechanism

From the characteristics of the destruction of the unbonded precast reinforced concrete overall framework , at the

beginning period of loading, there is no significant changes in the framework of beams; cracks appears later; the

structure distorts little; hysteresis curve shows elasticity rule; the residual deformation of the specimen is small.

With the load and horizontal displacement cycles increasing, the end of the beams appears cracks, and becomes the

plastic hinges. The tangent slope of the hysteresis curve decreases obviously. When the horizontal load adds up to

the limit load, the bearing capacity decreased slightly with the increase of the horizontal displacement. The structure

shows good ductility. The destruction of the unbonded precast reinforced concrete of the overall framework is

characterized by the appearance of a wide crack at the end of the beam , as shown in Fig. 3. At the same time, a

number of micro-column cracks appear at the root. At the later period of loading, the column root bears vertical

force, and the bar yields and shows plastic hinges. Failure mechanism of this structure consistents with the

principles of strong column and weak beam.

Fig. 3. Node beam damage characteristics

3.2. Hysteresis curves and skeleton curves.

Through data processing, the P- hysteretic curve of the specimens is obtained, as shown in Fig. 4(a); the

8/10/2019 1-s2.0-S2211381911000245-main

4/5

140 Jianqiang Han et al. / Systems Engineering Procedia 1 (2011) 137141

specimen skeleton curve shown in Fig. 4(b), wherePis the level force applied on the top of the framework, and is

the framework top horizontal displacement.

-100

-50

0

50

100

-150 -100 -50 0 50 100 150

P/kN

(a) (b)

Fig. 4. (a) P- ; (b) The skeleton curve of the sample frame

3.3. Eigenvalues measured displacement

The eigenvalues messured value of the displacement characteristics of the pre fabricated frame specimen, shown

in Table 2.

Table 2. Eigenvalues measured displacement between floors

Measurements YZKJ

1st floor 2nd floor

Forward Reverse Forward Reverse

Cracking story displacementucr/mm

Yield story driftuy/mm

Layer displacement ultimate loadumax/mm

Final layer displacementuu/mm

ucr/h

uy/h

umax/h

uu/h

1.01

4.82

46.2

63.0

1/1089

1/228

1/24

1/17

1.63

7.30

35.2

64.1

1/675

1/151

1/31

1/17

0.95

4.32

38.4

55.3

1/947

1/208

1/23

1/16

1.47

6.56

29.2

54.8

1/612

1/137

1/31

1/16

3.4. Finite element analysis

In this paper, we use SAP2000 finite element software to make the pushover analysis about the unbonded precast

frame structure model. The analysis results are shown in Fig. 5(a) and Fig. 5(b). We can see from the graph that the

ultimate bearing capacity of the nappe well agrees with the experimental value. Moreover, the SAP2000 nappe

plastic hinge sequence and location (outside the values in parentheses) and the testing process the order and location

of plastic hinges (values in brackets) are basically consistent.

8/10/2019 1-s2.0-S2211381911000245-main

5/5

Jianqiang Han et al. / Systems Engineering Procedia 1 (2011) 137141 141

(a) (b)

Fig. 5. (a) Base shear force and displacement curve; (b) Plastic hinge occurrence

Conclusions

Unbonded precast reinforced concrete frame structure has a better seismic performance for the earthquake zone

in the popularization and application of a consistent development of new industrial building structure system. By

assembling prestressed reinforced concrete frame structure test and finite element analysis, the following results can

be concluded for structural enginering design:

(1) Unbonded precast reinforced concrete frame structure after the first beam column hinge hinge failure

mechanism;

(2) The hysteresis loop of the overall framework of prestressing force shows that the structure has a good energy

dissipation capacity;

(3) The pre-fabricated steel wire compression enables to effectively improve the overall performance of the

framework and significantly improve the cracking load of the structure ;

(4) hysteresis curves showed obvious mold rope phenomenon, and has good resilience;(5) through the unbonded precast reinforced concrete frame structure finite element analysis, the experimental

results agree well with the theoretical results.

Acknowledgement

This research is funded by the National Science Foundation (NSF). The authors also acknowledge the College of

Civil And Architectural Engineering, Hebei United University and the Earthquake Engineering Rresearch Center of

Hebei Province. The findings and conclusions expressed in the paper are those of the authors and do not necessarily

reflect the views of the organizations, companies, and individuals acknowledged above.

References

1. M. J. Nigel Priestley: PCI Joumal. Vol. 47 (2002), p. 66

2. Blandon, John J. and Mario E: PCI Joumal. Vol. 50 (2005), p. 56

3. B. Liu, J. Tian and Y. Zhang: Journal of Building Structures (In Chinese). Vol. 28 (2007), p. 74

4. B. Liu, Y. Zhang and Z. Jin: Journal of Building Structures(In Chinese). Vol. 6 (2005), p. 60

5. J. Han and Z. Li: Journal of Industrial Construction(In Chinese). Vol. 39 (2009), p. 100

6. T. Dong: Experimental and Theoretical Research on Seismic Performance of Precast Prestressed Concrete Frame Structure with Unbonded

Post-tensioned Tendons[D]. Beijing University of Technology. 2006, 10.

7. D. Wang: Research of Seismic Performance and Reinforcement Performance of Precast Prestressed Concrete Connections with Unbonded

Post-Tensioned Tendons[D]. Beijing University of Technology. 2008, 06.

8. F. Qiu, J. Qian and Z. Chen: Anti-seismic Test Method[M]. Beijing: Science Press, 2000.