From SDOT:
The sidewalk on the south side of Pine Street from Ninth to Boren avenues, by the Paramount Theater, will be closed until May for Sound Transit’s light rail construction project. The closure is needed to prepare for tunneling under I-5 so the rail line can be extended from downtown to Capitol Hill and then on to the University of Washington.
Good thing they put a sidewalk on the north side of the Pine overpass, or the fairly heavy pedestrian rush hour would be spilling into the street (or, possibly, dutifully crossing over and over).