Biaxial behavior of plain concrete of nuclear containment building

To provide biaxial failure behavior characteristics of concrete of a standard Korean nuclear containment building, the concrete specimens with the dimensions of 200 mm×200 mm×60 mm were tested under different biaxial load combinations. The specimens were subjected to biaxial load combinations covering the three regions of compression–compression, compression–tension, and tension–tension. To avoid a confining effect due to friction in the boundary surface between the concrete specimen and the loading platen, the loading platens with Teflon pads were used. The principal deformations in the specimens were recorded, and the failure modes along with each stress ratio were examined. Based on the strength data, the biaxial ultimate strength envelopes were developed and the biaxial stress–strain responses in three different biaxial loading regions were plotted. The test results indicated that the concrete strength under equal biaxial compression, f 1= f 2, is higher by about 17% on the average than that under the uniaxial compression and the concrete strength under biaxial tension is almost independent of the stress ratio and is similar to that under the uniaxial tension.