In the past years, the strength of the connection structure between longitudinals and floor structures have been studied widely at laboratory levels and practical design levels. The authors developed a new type slot (APPLE SLOT) for the above connection structure, and investigated the elasto-plastic large deflection behavior of the floor structure with the new type slots, executing finite element elasto-plastic large deflection analyses and structural model experiments. In this report, the behavior of the floor structure with the new type slots under a compressive load is revealed, and the accuracy of finite element non-linear analysis regarding the combined stiffened structure with stress concentration parts by the new type slots is verifed.