The blast was an effort to remove the remaining pillars and road that did not come down during the deadly August 14 collapse that killed 43 people last summer.
While officials have not yet named an official cause, the bridge, first built in 1967, had undergone tremendous stress from the 25 million vehicles that traveled it on average every year and sea air that heavily corroded the steel rods suspending the road, the BBC reported.
Traffic and severe thunderstorms were likely catalysts as the bridge collapsed on the eve of Italy’s chief summer holiday, Ferragosto.
World-famed architect Renzo Piano, a Genoa native, has designed a replacement bridge that will feature 43 lamps dotting the span in tribute to those who lost their lives.
Genoa Mayor Mario Bucci said engineers will check to see if the nearby apartment buildings are still sound after Friday’s explosion. If they give the all-clear, residents will be allowed to return to their homes.
The Associated Press contributed to this report.