ATLANTA - A pedestrian bridge under construction collapsed Friday morning near the entrance of the Atlanta Botanical Garden, killing one worker and injuring 18 others.

Builders were working on the "canopy walk" that arches over a ravine to give visitors an elevated view of the new gardens when the structure gave way around 9 a.m. Joggers, dog walkers and others were in popular adjacent Piedmont Park north of downtown, but only workers were in the 30-acre garden that was closed to visitors, authorities said.

Electrical worker Juan Padilla and his partner were taking a break from working under the bridge at the time of the collapse.

"It sounded like an explosion," he said.

Padilla said he knew many of the victims, and fought back tears. "It was so tough," he said. "I feel very lucky. Me and my partner, we could have been under the bridge."

Two of 16 patients taken to Grady Memorial Hospital had brain injuries and others came in with hurt spines, backs and arms, said trauma surgeon Dr. Jeffrey Salomone. Four would be in intensive care, he said.

"The orthopedic injuries are potentially debilitating," he said.

Construction on the 600-foot long steel-cable-supported bridge began in September and its highest elevation was to be about four stories, according to information on the Botanical Garden Web site. A spring opening was planned for the 12-foot-wide skyway designed to let visitors walk among treetops.

"Our hearts go out to the family of the person that was killed," said Bill Pinto, president of Hardin Construction Co., which was doing the work.

Occupational Safety and Health Administration officer was at the scene to see if safety standards were followed, said OSHA spokesman Mike Wald.