Is there typically a pre-screening process for doctoral admissions in the US? I am applying to doctoral programs in the US and I am wondering: is it common for applications to be filtered before they reach the hiring committee? 

In the typical selection and admissions procedure for doctoral students, what happens after the deadline for applications has passed?
For US universities applications are almost universally prescreened for completeness and meeting any stated minimum requirements. The prescreen in process is almost always extremely rigid when minimum requirements are set. The wording on website is often confusing since sometimes schools want to be able to make special acceptances to people who do not meet the minimums. This requires someone from the department to beg and plead with the admin team. One place there is generally no flexibility at all is TOEFL requirements. It would be perfectly reasonable to call/email the department and ask, large departments get many such requests every year. Just realize that the answer will likely be the minimum is the minimum.