Cyclic loading test for reinforced concrete wall confined with prefabricated rectangular continuous hoops

초록

In the seismic design of reinforced concrete (RC) wall structures, the special seismic details, which include lateral confinements with closed hoops and crossties developed with 135 degrees degrees hooks and small spacing, are required to improve the ductility capacity of the walls. However, in the case of slender walls, such strict special seismic details are not feasible due to their small thickness (i.e., less than 200 mm). In this study, simple lateral confinement details with prefabricated continuous rectangular hoops (PRCH) were developed to improve constructability and deformation capacity. To verify the seismic performance of the walls with the proposed details, four walls with a high reinforcement ratio (rho v= 1.83 %) and high axial load (P /( A (g) f(c)') = 0.15) were tested under cyclic lateral loads. The major test parameters were the diameter of the continuous hoop, vertical spacing between the unit hoops, and horizontal spacing between the continuous hoops. The test results showed that the seismic performance of the walls with the proposed lateral confinements was superior to that of the walls without the lateral confinements in terms of the peak strength, ultimate deformation capacity, and energy dissipation. Further, the deformation capacity of the walls with the PRCH was 0.86-1.03 times greater than that of the walls with the special seismic details. Based on the test results, a parametric study was conducted using a finite element model to investigate the effects of design parameters on the deformation capacity of the walls with the PRCH. The major parameters affecting the deformation capacity were the vertical and horizontal spacing of the PRCH. Based on the test and parametric analysis results, design recommendations were suggested to determine the maximum vertical and net horizontal spacing of the proposed continuous hoops.

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