I'm not aware of any effect that can do this. If I was doing it I'd create a sound clip of exactly thirty seconds with zero volume, put the beep at the beginning, trim the track back to thirty seconds, import to your project, and copy paste as many times as you need. You can create the clip with just about any audio software you have - I would use Magix Audio Cleaning Lab (one of my personal 'best buys' software) or the free (but powerful) Audacity.
Insanity is hereditary, you get it from your children
One can add a Marker by tapping the * key on the numeric keypad. You could do this every 30 sec. (you can drag any about, if you miss the cue). Then, I'd use a "beep" SFX file, and place one at each of these Markers. If you have an SFX file that has any pre-roll in it, first thing that I'd do is alter it in Audacity, or any sound editing program, so that the actual "beep" comes at the very beginning of the Clip, and do a Save_As, then Import that edited SFX file.
Here is a list of possible sources for SFX (and music) files. Many are free, and some are for sale:Good luck,Hunt