MANCHESTER — The municipal complex will reach its first major construction milestone next week when the final steel beam of the new police station will be laid into place.

The police station is the final building on the municipal complex campus to have its steel frame completed, a sign that construction is moving toward completion.

To celebrate the progress of the complex, the city will hold a “topping off” ceremony at 9 a.m. Thursday, Dec. 1 at the municipal complex. Mayor Ted Gatsas, the Board of Aldermen, and staff from public works, highway and the police departments will be there to sign the final beam and watch it lifted into place.

Public Works Director Kevin Sheppard said the ceremony is not just for the police station, but for the entire site.

“We do want to memorialize it,” said Sheppard.

The $43.5 million municipal complex on Valley Street has been in the works since June 2010, when Gatsas presented a plan to the aldermen.

Gatsas argued that there was a severe need for updated facilities for public works and police and that Recovery Act loans that carried low interest rates and low construction costs made the project relatively affordable.

Construction began in March, and Sheppard said the project has been progressing as expected.

“The project is going very well — on time and within budget,” he said.

The municipal complex will house the public works, highway, parks and recreation and police departments, as well as a centralized vehicle storage and maintenance facility that would repair the entire city fleet.

The complex is located where the former highway building once stood and near Water Works headquarters. Sheppard said the public works building will be completed by June 2012. When asked if he was excited about a new office, Sheppard said he is “more excited about having a modern fleet maintenance building so our mechanics will have a safe place to work.”

The police station is scheduled for completion in December 2012, and the vehicle storage building will likely be finished sometime in 2013.

“Then the majority of the site will have been completed,” said Sheppard.