PORTSMOUTH — At about 4:30 p.m. on Wednesday, a steel I-beam from the World Trade Center will arrive in the city, under police escort, to the front of City Hall where it will be used as the centerpiece of a future 9/11 memorial.

Kathe Levesque, the Police Department's administrative assistant, said the idea for a permanent memorial came five years ago during an annual memorial ceremony in front of the police station. She said state Rep. Jacqueline Cali-Pitts mentioned it would be nice to have a permanent memorial and the idea grew from there.

After years of communicating with various officials and entities, the 8-foot steel I-beam, weighing 1,100 pounds, will arrive in Portsmouth on Sept. 2. Levesque said many volunteers, local business people and elected officials worked to obtain the beam. When the Police Department was notified in early August that it would receive on the artifacts, Levesque said, "It was like Christmas."

The Police Department announced the beam will be escorted from JFK International Airport in New York by a five-vehicle police motorcade. It will leave New York on Wednesday at 9:30 a.m. and the Police Department has invited other police agencies to follow their travel route and join in along the way.

The motorcade will escort the beam up Interstate 95 and into Portsmouth by Market Street extension, police announced. The motorcade will then travel up Market Street and through Market Square before moving on to Junkins Avenue to the police station. The estimated time of arrival in Portsmouth is 4:30 p.m., according to police.

Police said Chief Steven DuBois will tweet live about the motorcade's progress at (@portsmouthchief).