Wisconsin appears to require even students directly admitted to chemical engineering to maintain a 3.5 major and 3.0 overall GPA to remain in the major. https://www.engr.wisc.edu/academics/student-services/academic-advising/first-year-undergraduate-students/progression-requirements/
While the program may have a top-end reputation, it weeds heavily. According to https://registrar.wisc.edu/grade-reports/ , it looks like first year chemical engineering students have an average GPA slightly under 3.5, so probably around half of them are weeded out of the major. The grade distributions by course suggest that fewer than half of students enrolled in frosh-level chemistry and physics courses earn A (4.0) or AB (3.5) grades.