I've just finished reading the first in a new hard SF series.
Bowl of Heaven by Gregory Benford and Larry Niven.
I don't think it is a spoiler to say that it involves interstellar ramships and an artifact a bit like a mobile Ringworld. (Cupworld?)
The science is (as expected) well researched. Story line and characterisation are ok but a bit clunky after Weber, still well worth reading.
I do love big concepts, and they don't come much bigger than this