NB I-280 closed in San Francisco for seismic retrofit

SAN FRANCISCO -- Northbound Interstate Highway 280 in San Francisco closed Thursday afternoon and will remain closed through the Labor Day weekend as large sections of the highway are removed and new hinges are installed to seismically strengthen an overpass, a Caltrans spokesman said.

Drivers will not be able to access a stretch of northbound Highway 280, from the U.S. Highway 101/Highway 280 interchange to San Francisco's South of Market neighborhood, starting at 2 p.m. Thursday.

Two large sections of the roadway are being removed and then replaced with reinforced sections, according to Caltrans spokesman Steven Williams.

The closure of northbound Highway 280 is scheduled to continue until 5 a.m. Tuesday. All northbound Highway 280 traffic will be detoured onto Highway 101, Williams said.

The two pieces of roadway that will be removed are each about 24 feet wide, 48 feet long and 5 feet thick, he said.

The highway hinges were designed in the 1960s and an inspection seven years ago determined they were in need of replacement in order to withstand a large earthquake.

Caltrans crews will replace the hinge on the first section, running above the Dogpatch neighborhood, then will move south toward Highway 101, where the second section will be removed and the hinge replaced, according to Caltrans.

Williams said the closure of northbound Highway 280 has been a long time coming and was not spurred by the 6.0-magnitude earthquake that damaged roads and buildings in Napa and Solano counties early Sunday morning.

The planned closure is the third this year. The highway was also closed in the area for similar seismic strengthening during the Memorial Day and Fourth of July holiday weekends.

Over the Labor Day weekend, motorists can call 511 or visit 511.org for more information about the closure and any changes in the reopening time.

Motorists are advised to use public transportation such as BART, Caltrain, San Francisco Municipal Railway and SamTrans to avoid heavy traffic in the area caused by the detour.

While the freeway is closed, avoid traffic jams by downloading the ABC7 News Waze app.