The city has ordered nearly 400 residents and everyone else to get out of a safety zone that extends about 1,000 feet in all directions from the Davis Avenue Bridge, which is scheduled to be brought down by explosives this afternoon.

Almost no one who is not on the blasting team or in a helicopter will be allowed to witness the demise of the 110-year-old North Side bridge, set for 2 p.m.

But yesterday, Janice Stauffer, who lives on Woods Run Avenue in the shadow of the decrepit span, said she wasn't inclined to leave.

"We're going to try to stick it out. These are our homes," said Ms. Stauffer, whose house is about 100 yards down from where the bridge towers over her street. Her next-door neighbors also planned to stay, she said.

City officials told about 400 residents on 12 streets in the safety zone to be out by 11 a.m. today, remove all vehicles and pets, and close all windows, doors and air intakes, including exhaust fans, to protect against dust.

"There is absolutely no safe place to watch the event from the ground," read a statement by Joanna Doven, spokeswoman for Mayor Luke Ravenstahl. "Police officers will be patrolling the safety zone and its perimeter to ensure that everyone has evacuated. The implosion will not take place if anyone -- residents, thrill-seekers, or media personnel -- is inside of the safety zone."

The city said it hoped most residents could return an hour after the demolition.

Controlled Demolition Inc., the Maryland firm that is blasting the bridge, has put protective fabric over the homes closest to the bridge and built an earthen levee beneath it to cushion the impact of tons of falling steel.

Just under 70 pounds of an explosive called RDX has been placed in linear-shaped charges at 122 spots on the bridge. When detonated, it will cut through and melt the steel structure, dropping it straight down to the valley floor about 70 feet below.

The detonation will take about six-tenths of a second. As for the sound, Jim Santoro, a project manager with Controlled Demolition, said, "I would be surprised if they didn't hear it Downtown," nearly three miles away.

Mr. Santoro said the extended safety perimeter was created because officials don't want anyone in a building if windows break, and because of the remote chance of flying debris from the explosives.

The copper shielding on the 18-inch-long charges will melt at detonation. Unprotected, bullets of molten copper could travel several thousand feet, resolidifying in mid-air, he said. To guard against that, the charges are wrapped in rubber blankets reinforced with fiberglass cording.

Bad weather -- thunderstorms, heavy rain, low clouds or fog -- could postpone the blast, Mr. Santoro said. Sound travels better in dense air, increasing the possibility of damage, especially to windows, he said.

Amid the growl of construction equipment yesterday, workers in baskets on towering cranes put the finishing touches on the skeleton of the doomed bridge.

Ms. Stauffer's husband mowed the lawn.

"I'm just not happy with the way this whole thing has been handled," she said. "They should've done something with this bridge a long time ago."

The bridge was closed to vehicles in August 2001 but left open to pedestrians. Mr. Ravenstahl declared an emergency and ordered it demolished after a recent inspection concluded that it was in imminent danger of collapse.

A lifelong resident of Woods Run, Ms. Stauffer said her street offered "peaceful, quiet, almost country living" until the bridge closed, redirecting much of its traffic to Woods Run Avenue.

She said she doubts the city's ability to keep looters and other troublemakers away while residents are away.

She said if she leaves, it will be "not without us kicking and screaming."

City Public Safety Director Michael Huss was adamant. Scores of police officers and other safety personnel will scour the area today, making sure everyone is out.

"We cannot bring this bridge down until everybody's out of the safety zone," he said.