We have been restoring The Lyric Theatre for about 9 months now, with a completion date scheduled at year’s end. To create a state of the art rigging system at the stage fly, we recently installed micropiles. They carry the load of four 65’ columns that are supporting about 25 tons of load individually.
Our drilling ranged up to about 35 feet deep, with the last 5’ of casing embedded into bedrock. Within each casing, we then placed a threaded bar to full depth and grouted to the top. We installed steel plates for each casing, and a concrete cap on top of each micropile grouping.
The new steel rigging structure will be a completely independent structure within the 100-year-old Lyric stage fly space, with no impact to existing walls or foundations. The selection of micropiles allowed for a structural foundation system that could be installed in the confines of the existing basement with special drilling equipment that could fit under the 7’ headroom of the stage floor. This unique application of a foundation system allowed greater flexibility when dealing with dimensional constraints and areas of historic preservation.