Many specialties contribute to the manufacture of prestressed concrete. Materials scientists, chemical engineers, metallurgical engineers, mechanical engineers, structural engineers, tooling engineers to design casting beds, quality control engineers, etc.

But in the early days of prestressed concrete (1920, 1930), a single civil engineer performed all of these functions.

The point is that the role of the modern civil engineer has changed and specialized over the decades. You can be a very competent civil engineer without having the knowledge or experience needed to perform every specialty.

Just because our ancestors in the 1940s handwrote binary sequences, and in the 1950s they handwrote assembly, and in the 1960s they handwrote FORTRAN, doesn't mean that today's software engineers need to be able to do any of that.