Pseudo-dynamic tests

In order to determine the lateral displacement and load bearing capacity of the strengthened system, a displacement control reversed cyclic loading up to 66 mm of top displacement was applied to the specimen after the pseudo-dynamic tests. Figure 10.8 shows the reverse cyclic displacement protocol for the top story of the test frame. The cyclic displacement histories applied to the first and second stories were consistent with the first modal shape of the test frame. They were determined using the method proposed by Molina et al. (1999) and Maia and Silva (1997) by taking the top story displacement protocol into consideration. 

At the end of the pseudo-dynamic tests, a reversed cyclic loading was applied on the test specimen in order to investigate the residual lateral load carrying capacity and the displacement capacity of the enhanced frame. 

Pseudo-Dynamic Tests of 4-Storey Non-Ductile Frames with RC Infilling of the Bay... 

Pseudo-Dynamic Tests of 4-Storey Non-Ductile Frames. 

The specimens were subjected to pseudo-dynamic testing under the 15 s-long Y component of the Herzegnovi record in the 1979 Montenegro earthquake, scaled to a peak ground acceleration (PGA) of 0.25g and modulated as in Fig. 16.3a to... 

Fig. 16.3 Ground motion applied in pseudo-dynamic tests (a) acceleration time-history after Y component of Herzegnovi record in 1979 Montenegro earthquake (b) 5 %-damped elastic spectrum compared to target Type 1 spectrum in Eurocode 8 for ground type C (factor 40.75 applied on the time- and period axes to account for the specimen scale)...

For technical reasons, only two out of four degrees of fireedom (DoFs) were included in the pseudo-dynamic tests those of floors 2 and 4. The other two DoFs were statically condensed. One-half of the tributary mass of 43,375 kg of each one of the 1st and 3rd floors was lumped to the nearest DoF. 

In the pseudo-dynamic test all repaired cracks re-opened, but the one at the base section became dominant. At the time when the drift ratio at the top of the wall was 1.0 % (Fig. 16.6), the base section reached its ultimate deformation in flexure (conventionally identified with a 20 % drop in the moment resistance of that section compared to its peak prior value). At that point the ultimate chord rotation of the shear span of the base section ( moment-to-shear ratio, measured during the test to be 6.75 m on average) was 10.5 mrad, the crack at the base had opened to 2.5 mm and at the bottom of the 2nd storey to 1 mm. 

Fig. 16.6 Response of specimen no. 1 in pseudo-dynamic test base moment vs. top drift ratio...

Fig. 16.9 Damage to specimen no. 2 during pseudo-dynamic test (a) damaged lap-splice region at the base of the 2nd storey extending into horizontal flexural damage along the 1st storey beam (b) close-up of flexural damage in the 1st storey beam...

Fig. 16.10 Bending moment vs. rotation with respect to the base in pseudo-dynamic test of specimen no. 2...

Fig. 16.11 Storey shear vs. interface slip in pseudo-dynamic test of specimen no. 2 (a) at the interface of the web of the 2nd storey to the beam between the 1st and 2nd stories (b) at the interface between the web and a column in the 2nd storey...

The pseudodynamic test of this specimen was interrupted at about 5.5 s. The damaged specimen was subjected to a full-duration pseudo-dynamic test, exhibiting softer response than specimens no. 1 or 2. 

Wall no. 3 had less web reinforcement than specimen no. 2 and much less than no. 1 (see Table 16.2). Nevertheless, its overall behavior in the pseudo-dynamic test was very similar to that of specimen no. 1 two major flexural cracks opened early on, one at the base section and the other across the ends of the long dowels connecting the web to the footing, with the one at the base soon becoming dominant (Fig. 16.12). 

Table 16.3 lists key results from the pseudo-dynamic tests. 

Table 16.3 Summary of pseudo-dynamic test results...

Fig. 16.15 Time-histories of floor displacements in pseudo-dynamic test of specimen (a) no. 1 (b) no. 2 (c) no. 3 (first, intermpted test and fiill-diuation test of damaged specimtm)...

Pegon P, Molina FJ, Magonette G (2008) Continuous pseudo-dynamic testing at ELSA. In Saouma VE, Sivaselvan MV (eds) Hybrid simulation theory, implcanentation and applications. Taylor Francis/Balkema Publishers, London, pp 79-88 Shiohara H, Hosokawa Y, Nakamura T, Aoyama H (1984) Tests on the construction method of seismic rehabilitation of existing reinforced concrete buildings. In Proceedings, vol 6. Japan Concrete Institute, Tokyo, pp 405-408... 

Substructure Pseudo-Dynamic Tests on Seismic Response Control of Soft-First-Story Buildings... 

In this study, six-story piloti reinforced concrete (RC) frames are experimentally tested, in order to examine the effectiveness of steel dampers in reducing the structural damage. Two sets of structural models are compared to each other through substructure pseudo-dynamic tests. 

In order to conduct the substructure pseudo-dynamic test, the prototype structure is modelled in two parts. One is the actual specimen which is experimentally tested so that the elasto-plastic behavior of the critical part of the structure is realistically represented. The behavior of the other part, which is expected not to critically affect the total response of the structure, is numerically calculated using a conventional nonlinear computational approach. The substracture pseudo-dynamic test is developed on a basis of pseudo-dynamic testing, which is an experimental technique for simulating the seismic response of the tested structure or component. 

The procedure for the substructore pseudo-dynamic tests in this study is as follows ... 

The seismic energy response of soft-first-story frames is discussed based on the results of the substructure pseudo-dynamic tests. The total input energy, Ej, and... 

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