Conservation in Action: Juno, Structural stabilization of the body, December 2011

Relocation and conservation of a Roman sculpture of the goddess Juno, early second century A.D.:
December 2011, Structural stabilization of the body

Post tensioning is the selected method by which the fractured body will be stabilized. Below is a drawing (by structural engineering firm Weidlinger Associates, Inc.) detailing the procedure.

Core drilling (by Jack Moore Associates, Inc.) into the torso through the original hole at the top of the neck allows the setting of an eight-foot vertical threaded steel rod. The rod, anchored at the bottom with epoxy resin, extends into the center of the sculpture and bridges the crack at the waist.

A plywood enclosure surrounds the top of the figure, to provide a solid flat surface against which the tension plate can be bolted. To secure the enclosure in place, the spaces between the plywood and the sculpture are filled with plaster, after the surface of the marble is first protected with a thin layer of polyethylene.

A steel plate (below) with welded nuts is threaded onto the rod to provide post tensioning. The tensioned rod stabilizes the statue, from the bottom section below the crack at the waist to the torso above the crack. The holes in the plate are grout ports. After tensioning the rod, the cored hole is filled with grout, so that the rod will remain in tension when the steel plate is removed later.

See next update.