**2. Outlines of tests**

#### **2.1 Test specimens**

The viaduct model (**Figure 1**) was constructed at a 1/10 scale of a full-size viaduct structure. The PC girder of the viaduct structure was considered as the experimental substructure. It was reasonably assumed that the viaduct girder was symmetric with respect to the center of each bay. This assumption was made for simplicity and due to the difficulty of implementing members with different inflection points, and because of the linearly varying moment distribution. Consequently, the PC girder was assumed to be composed of two identical cantilever members satisfying compatibility and equilibrium conditions at the center. Only half of the PC girder was considered as the experimental member (**Figure 1a**). The model numbering scheme, dimensions, and degrees of freedom are shown in **Figure 1b**.

Two partially PC specimens representing the experimental PC girder members of the viaduct models and named B-1 and B-2 were tested. The specimens have the same dimensions, reinforcing bars, and prestressing tendons arrangement. Specimen B-1 was tested using a statically reversed cyclically loading, while specimen B-2 was tested using a sub-structured pseudo-dynamic test. The upper part of each specimen (**Figure 2**) represents the PC girder part. The PC girder part was placed monolithically with a lower part. The lower part represents the momentresisting connection and the upper part of the reinforced concrete column of the viaduct model. The lower part has sufficient rigidity to allow the observation of the damage of the PC girders during testing.

The PC girder part has a depth of 25 cm, a width of 20 cm, and a length of 200 cm. The lower part of the specimen has a depth of 50 cm, a width of 50 cm, and a length of 120 cm. The girder part has two reinforcing bars with 13 mm diameter at each side of the section. The girder part has one D11 mm prestressing

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**Figure 2.**

**Figure 1.**

spaced at 8 cm.

*Seismic Hazard of Viaduct Transportation Infrastructure*

tendon at each side of the cross section (**Figure 2**). The mechanical prestressing ratio of the specimens is 0.55. The design philosophy implicitly requires that shear failure be prevented or delayed so that the member under consideration may dissipate, by flexure, energy larger than required for the applied earthquake. Therefore, relatively close-spaced transverse hoops were arranged for the entire length of the girder part. The rectangular hoops were 3 mm in diameter and were

*Experimental test specimen and model used during the sub-structured pseudo-dynamic testing: (a) Experimental* 

*test specimen; (b) model used in the sub-structured pseudo-dynamic testing.*

*Test specimens and loading setup: (a) test specimens; (b) loading setup.*

*DOI: http://dx.doi.org/10.5772/intechopen.85700*

*Seismic Hazard of Viaduct Transportation Infrastructure DOI: http://dx.doi.org/10.5772/intechopen.85700*

#### **Figure 1.**

*Natural Hazards - Risk, Exposure, Response, and Resilience*

and results obtained from response analyses was made.

dimensions, and degrees of freedom are shown in **Figure 1b**.

damage of the PC girders during testing.

**2. Outlines of tests**

**2.1 Test specimens**

forces. Moreover, few research studies have been carried out to study the effect of

On the other hand, because of the monolithic moment-resisting connection between the superstructure and the columns of the viaduct structures, less bending moments were expected in the bottom ends of the columns, and other plastic hinges at the tip of the columns may result to allow for some energy dissipation at these locations. Additionally, not only the columns but also the girders might have some damage. Yet not enough tests have been performed to study the inelastic response behavior of the partially prestressed concrete (hereafter known as PC) girders of the viaduct structures [5–7]. The objective of this study was to obtain the inelastic response behavior of such PC viaduct structures due to severe earthquake excitation. A study that includes experimental and analytical phases was carried out. Specimens representing the PC girders of the viaduct structures were tested experimentally. Statically reversed cyclic loading and sub-structured pseudo-dynamic testing were conducted. The objective of the statically reversed cyclic loading test was to study the inelastic response behavior of the PC girders and to obtain the hysteretic-load deformational characteristics. During the sub-structured pseudodynamic test, the PC girder was tested experimentally, and the RC columns of the viaduct structure were simulated analytically. Response analyses for the viaduct model in terms of hysteretic moment-rotation curves and time histories were carried out. The plastic deformability expressed in terms of the ductility factor and the dissipated energy was examined. A comparison between the experimental results

The viaduct model (**Figure 1**) was constructed at a 1/10 scale of a full-size viaduct structure. The PC girder of the viaduct structure was considered as the experimental substructure. It was reasonably assumed that the viaduct girder was symmetric with respect to the center of each bay. This assumption was made for simplicity and due to the difficulty of implementing members with different inflection points, and because of the linearly varying moment distribution. Consequently, the PC girder was assumed to be composed of two identical cantilever members satisfying compatibility and equilibrium conditions at the center. Only half of the PC girder was considered as the experimental member (**Figure 1a**). The model numbering scheme,

Two partially PC specimens representing the experimental PC girder members of the viaduct models and named B-1 and B-2 were tested. The specimens have the same dimensions, reinforcing bars, and prestressing tendons arrangement. Specimen B-1 was tested using a statically reversed cyclically loading, while specimen B-2 was tested using a sub-structured pseudo-dynamic test. The upper part of each specimen (**Figure 2**) represents the PC girder part. The PC girder part was placed monolithically with a lower part. The lower part represents the momentresisting connection and the upper part of the reinforced concrete column of the viaduct model. The lower part has sufficient rigidity to allow the observation of the

The PC girder part has a depth of 25 cm, a width of 20 cm, and a length of 200 cm. The lower part of the specimen has a depth of 50 cm, a width of 50 cm, and a length of 120 cm. The girder part has two reinforcing bars with 13 mm diameter at each side of the section. The girder part has one D11 mm prestressing

prestressing the reinforced concrete piers of highway bridges [3, 4].

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*Experimental test specimen and model used during the sub-structured pseudo-dynamic testing: (a) Experimental test specimen; (b) model used in the sub-structured pseudo-dynamic testing.*

**Figure 2.** *Test specimens and loading setup: (a) test specimens; (b) loading setup.*

tendon at each side of the cross section (**Figure 2**). The mechanical prestressing ratio of the specimens is 0.55. The design philosophy implicitly requires that shear failure be prevented or delayed so that the member under consideration may dissipate, by flexure, energy larger than required for the applied earthquake. Therefore, relatively close-spaced transverse hoops were arranged for the entire length of the girder part. The rectangular hoops were 3 mm in diameter and were spaced at 8 cm.

The specimens were fixed to a testing floor by the use of side supports, prestressed rods, and high-strength bolts. The loading was applied through an actuator that was fixed at a height of 150 cm from the bottom end of the PC girder of each specimen (**Figure 2**). The corresponding a/d ratio is 6.8. The average compressive cylindrical concrete strength is 400 kgf/cm2 . The yield strength of the reinforcing bars is 3400 kgf/cm2 , and the yield strength of the prestressing tendons is 12,200 kgf/cm<sup>2</sup> . Details of the specimens are shown in **Figure 2**.

## **2.2 Statically reversed cyclic loading testing**

Statically reversed cyclic loading test was carried out for specimen B-1. The objective of conducting this test was to clarify the load-displacement characteristics of the PC girders. The specimen was tested using the setup shown in **Figure 2b**. The setup consisted of the specimen, actuator, reaction wall, testing floor, data loggers, computer for data acquisition, and displacement measuring devices. The yield displacement was the measured displacement corresponding to the recorded yield load. The imposed displacements to the specimen through the actuator were multiples of the prestressing tendons yielding displacement. Ten repetitions of each cycle were considered. Typically, ten repetitions cannot be attained during a real severe earthquake, but they were planned to fully clarify the load-displacement characteristics. **Figure 3** shows the input displacements that were applied to specimen B-1.

## **2.3 Sub-structured pseudo-dynamic testing**
