Figure 5 Test set-up for SP beams Table 2 Results of bending loading test

Figure 6 shows crack formation in SP-4. When the load reaches 118 kN, axial cracks at the position about 45 degrees from the upper end of the concrete developed and the concrete separated from the steel pipe. Along with

the development of flexural cracks, shear cracks were observed. When the load exceeded 392 kN, shear cracks were remarkable near the loading points. Finally, crushing of concrete occurred between the loading points. Destruction of steel including studs was not observed. Similar to SP-4, shear failure was dominant in SP-5 and SP-6.