抄録
In order to apply limit state design method to tube structure like tunnels the authors conducted loading tests on a tube model and verified the fracture process for tube structures. According to the test results, even when the sectional force locally exceeded the sectional force capacity in the tube structure and cracking developed, the structural body did not collapse, and it was confirmed that the structural force capacity was greater than the sectional force capacity. With the design of tube structures, regarding the point when the sectional forces reach the force capacity as one of the limit states, the sectional force and the force capacity were checked. In calculation of the sectional force capacity, it was decided that it was all right to consider this as the state when cracking occurred.
With steel fiber reinforced concrete (SFRC), it was seen that the sectional force capacity becomes larger than that of plain concrete, and that the force capacity differs depending on factors such as the shape and content of steel fibers, because the tensile stress is transmitted through the steel fibers intersecting the crack surface even after cracking has developed.
However there are almost no methods to calculate the sectional force capacity, with consideration of the tensile stress transmitted through the steel fibers, and there are few examples of applying steel fiber reinforced concrete to structural members. Therefore in this paper a method to calculate the sectional force capacity in steel fiber reinforced concrete is proposed based on fracture mechanics.
