A crane began lifting 120-foot steel trusses from the roof area of the Gaillard Auditorium this morning, continuing the demolition phase of the Calhoun Street municipal center’s $142 million overhaul. Demolition is scheduled for completion in December 2012, and construction is expected to be finished by December 2014.

Removing the trusses, which weigh over 20,000 pounds apiece, is no small feat. Reporters were invited to witness the removal at 8 a.m., and by 10 a.m., the demolition crew was still taking measurements to align the crane hooks on the first truss. The brick, concrete, and structural steel that are removed during demolition will be recycled.

The new Gaillard Center will include city offices, a 15,000-square-foot ballroom and exhibition hall, and a theater with 1,800 seats. The theater will be smaller than the old 2,600-seat space but will feature improved acoustics and three tiers of balcony and skybox seating in a horseshoe configuration. According to Project Executive Bob Ferguson, construction is actually set for completion in October 2014, allowing 60 days for an acoustician to “tune” the auditorium, measuring reverberations inside the concert hall and either adding or taking away material to optimize the listening experience.

The east end of the Gaillard, facing Alexander Street, will remain largely the same, with the current columns intact and the existing bricks replaced by new ones. Part of the brick facade fell off in 1989 during Hurricane Hugo and had to be replaced, and during demolition this year, the rest of the bricks were determined to be at risk of detaching in the next hurricane or earthquake.

One feature that neighbors will appreciate during the construction phase: The new Gaillard will be built with augercast piles, which can be installed more quietly than traditional driven piles such as the ones that were used at Buist Academy earlier this year (Remember that head-splitting clanging sound?). Holes will be drilled in the ground and then filled with concrete, requiring no hammering.

The demolition and construction project is being conducted by Skanska USA and Trident Construction Company, with Skanska holding about 70 percent of the contract. Skanska’s previous projects in the Charleston area include the Market Pavilion Hotel and Wando High School.