From WSDOT:
Northbound I-405 will be closed this weekend. Crews will close northbound I-405 between N.E. Eighth Street and SR 520 beginning at 11 p.m. Friday Sept 30 to re-stripe and connect new on-ramps. When I-405 reopens at 4 a.m. Monday Oct 3 , drivers will use new ramps to get to I-405 and SR 520.