Back-Seat Driver

L Street work downtown causing major traffic jams

L Street downtown has probably never been more of a mess than now.

Construction trucks and equipment are camped out day and night in the street’s center lane, and crews periodically have been closing a second lane, leaving only one lane open, causing commute-hour backups past the state Capitol.

Here’s the surprise: The mess has nothing to do with the arena construction at Sixth and L streets.

It’s part of the city’s long effort to rebuild its sewer system. The city has been adding 6-foot-wide pipes under the middle lane of L between Seventh and Ninth streets since September. Dale Mathison, the project manager, said the L Street portion of the project should be finished by the end of March, with perhaps some asphalt resurfacing work extending into April.

Sewer pipes also are being laid on Seventh Street for a few blocks south of L Street. That work should also be done by the end of March. But, sad to say, that is not the end of the mess downtown. In late summer, the city will begin laying new sewer pipes under Ninth Street, between G and L streets.

It’s been tricky. Not only is downtown full of cars, it is crisscrossed by light-rail trains. Mathison said the city is using a tunnel-boring machine to avoid extra traffic hassles by reducing the amount of street surface that gets ripped up. It also allows the work to be done without having to tear up light-rail train tracks.

How to raise a bridge?

Reader Michael O’Brien poses an interesting question about state Department of Transportation’s ongoing “Raise 80” project in Placer County. Over the course of about a year, the state is increasing the height of a handful of freeway overpasses. They need to be at least 16 feet, 6 inches, Caltrans officials say, tall enough for taller commercial trucks, and to meet federal height standards for national security equipment to pass through.

O’Brien: How exactly do you raise a bridge? Caltrans: Not easily. “The mechanics are amazing,” said Caltrans’ Liza Whitmore.

Here is a simplified version: Crews close the freeway for two nights so they can set up heavy-duty braces under the bridge deck. Then they slice horizontally through the bridge’s support columns. They also cut the bridge deck free at the top from the walls that hold it up on the sides. It’s like slicing the bridge off at the knees and detaching it from its arms (temporarily).

They jack the freed section of the bridge up, an inch at a time, then reattach it to the lower portion of the columns and to its side abutments with new reinforced concrete. They regrade the road leading up to each on each side, and rebuild the sidewalks.

Next up is the Gilardi Road overcrossing near Penryn on Tuesday and Wednesday nights. We just may head out there and take some video to post on to give you a better idea about what clearly is a delicate process.

Call The Bee’s Tony Bizjak, (916) 321-1059.