The accident happened on Thursday morning on the Tim Maia cycling path, which joins the districts of Sao Conrado and Leblon, when a large wave hit one of its support pillars, leading a section of it to collapse, XInhua news agency reported.
A 50-metre stretch of the cycling path, which had only been opened in January, fell apart on Thursday. The path was built alongside the Niemeyer Avenue and opened in January to link up with two other, older sections.
Running for 3.9 km, the cycling path cost the city 44.7 million reais ($12.6 million).
Speaking from Athens, Greece, where he was attending the Olympic Flame lighting ceremony, Rio’s mayor Eduardo Paes said “what has happened is unforgivable” and promised “an immediate investigation into the facts”.