I've used mesh fiberglass tape (the type you buy for wall repairs), combined with JB ClearWeld. It worked really well repairing my STTNG Subway which, of course, is hidden from view. It's nice that your ramps aren't clear, so that will help hide the repair work some. You should sand the surface of the plastic, to achieve a better bond with the clearweld.
There was a big chunk of the plastic missing, and I've attached a photo showing the after effect. It's not the prettiest, but I wasn't going for pretty. I was going for strong.
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