We conducted a crack survey of floor slabs in distribution warehouses up to 5 years old. As a result, the crack coefficient at 5 years of age was about 70 × 10-6 to 100 × 10-6 on the 2nd and 3rd floors, and about 30 × 10-6 on the 4th floor. The reason why the 4th floor is smaller than the other floors is that it is used less frequently than the other floors and is less affected by external forces such as vehicle running, and the slab is less restrained than the other floors.
