A giant overpass being built over one of California's busiest freeways has caught fire and collapsed completely, necessitating the demolition of the entire project.

According to the San Bernandino County Fire Department’s Twitter account, the blaze was caused by construction workers who were using blowtorches to cut through the reinforcing bars of the bridge, which passes over the busy 15 Freeway linking Los Angeles and Las Vegas.

The blowtorches accidentally set fire to the timber falsework for the overpass at around 1:30 pm local time, triggering a blaze which rapidly engulfed the whole structure. The freeway was shut down in both directions as a team of five fire engines and over 60 firefighters arrived at the scene to quell the conflagration.


Their efforts were to prove in vain, however, as heavy winds approaching 60 kilometres an hour fuelled the raging fire for over two hours, causing construction debris to spill onto the freeway below. The destruction of the chief support structure by the blaze eventually caused the bridge to collapse completely.

Tracey Martinez, spokeswoman for the San Bernandino County Fire Department, said that the heat of the fire was so intense that it burnt the asphalt on the freeway, and caused the steel beams of the bridge to glow.

The disruption to freeway traffic caused by the overpass collapse resulted in a kilometres-long traffic jam running in both directions in Hesperia, San Bernadino County.

Work on the $31.7 million dollar bridge in Hesperia, San Bernandino County, commenced at the beginning of 2013. If completed as scheduled in the spring of 2015, the bridge would have covered an area roughly the size of a football field.

The bridge itself is part of the $59 million Ranchero Road Interchange Project,which will connected a number of main roads in the region to Interstate 15 via a full service interchange.

The destruction caused by the blaze has left the bridge in a completely irretrievable state, with construction crews gradually demolishing what remains of it as fire-fighters endeavour to prevent any embers from triggering subsequent fires.

Division Chief Britt Sipe of the San Bernandino County Fire Department said that the bridge was being dismantled one chunk at a time and fires continually extinguished as crews proceeded. While crews are working as fast as they can in order to reduce traffic disruptions, safety risks involving heavy timber and iron beams have hampered efforts.

“There’s nothing to save: the bridge collapsed,” said Caltrans spokesman Terri Kashinga. “I think it takes them right to the beginning…they have the ramps done, but this is a major, major loss.”