Based on the test results of walls with Grade 550 MPa and aspect ratio of 2.0, it was found that the behavior of the wall is close to that of wall with Grade 420 MPa, which is the maximum permissible strength of shear reinforcing bars in ACI 318 (or ACI 349). The findings can be used as an evidence to increase the permissible maximum strength of shear reinforcing bars for shear walls with aspect ratio less than 2.0 in ACI 318(or ACI 349).

In the construction of nuclear power plants using massive walls in Korea, the use of high-strength re-bars for shear design is necessary to enhance the constructability and economy. In the present study, low-rise walls(aspect ratio = 1.0) with 550MPa grade bars, were tested under cyclic loading to investigate shear capacity and deformation capacity of the walls. The results were compared with the performance of walls with grade 420 bars and predictions by current design code. The test results showed that ACI 349 underestimated the shear strength of the walls with 550 MPa grade bars. This result indicated that the ACI 349 predictions can be safely used for the earthquake design of the low-rise walls (aspect ratio =1.0) with 550 MPa grade bars.