Both eastbound Interstate 90 and westbound Highway 520 will be choked by construction this weekend, similar to other recent closures.

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Construction this weekend will block lanes on the Lake Washington floating highways, causing delays on both sides of the water.

• Interstate 90 eastbound will be funneled into one lane at Rainier Avenue South in Seattle, where all mainline traffic to the Eastside will detour into the express lanes. The work runs from 11 p.m. Friday until 5 a.m. Monday.

This is part of a continuing project to install new lighting, fire-suppression devices and future carpool lanes in the Mount Baker tunnels and Mercer Island lids, before light-rail construction takes over the express lanes in 2017.

• Highway 520 westbound will close from the east shore to Montlake Boulevard, from 6 a.m. Sunday until 5 a.m. Monday.

Workers will be drilling on the 24th Avenue East overpass, which runs above the highway, to create new interchanges for a future six-lane crossing.

• The Jingle Bell Run/Walk for Arthritis will go through downtown at 7 a.m. Sunday, along Fifth Avenue, the Interstate 5 express lanes and Pine Street.

Looking ahead, Highway 99 lane closures are planned at South Lake Union the following weekend, for crews to build a permanent median near Denny Way. And in early 2016, single-lane closures of up to seven weeks will occur nearby, to install horizontal beams for overhead signs and toll devices.

In other transportation news, tunnel machine Bertha’s two-year stall is nearing an end — sand arrived Thursday to refill the giant drill’s repair vault, the state pit-cam shows.

Chris Dixon, project manager for Seattle Tunnel Partners (STP), said the sand will be poured early next week, and he expects the machine to be tested and ready by Dec. 23. However, Dixon said STP may wait until January to resume the Highway 99 tunnel dig toward downtown, to give workers a holiday.