Japan Architecture - Gate Tower, the Skyscraper Pierced by a Highway

One of the most interesting images seen in Osaka from the Umeda Sky Building observatory was this famous skyscraper traversed by a highway, the Gate Tower Building.
Interesting, there is no connection between the two structures, the highway passes through the building like a tunnel, wrapped in the noise protection walls visible in the photo. Also, the floors 5, 6 and 7, adjacent to the highway contain only elevators, stairways and machinery.

How did they come to this extreme solution?
The land was owned by the Suezawa Sangyo company, which in 1983 started to plan an office building. However, the land was also included in the Hanshin Expressway plans for the highway construction, so a 5-year-long fruitless negotiations took place. In 1989, because of a similar issue in Minato-ku, Tokyo, the building codes were changed to allow the development of buildings and highways in the same space (multi-level road system). In the end the project from Tokyo was abandoned, so the Gate Tower Building from Osaka, finished in 1992, became the first building in Japan having a highway passing through it.