Underpinning the Salt Lake Temple-Video

Video Transcription

Video Summary

Rob Jamieson and Eric Chambers describe the underpinning of Salt Lake Temple, a historic, unreinforced masonry building being upgraded to withstand earthquakes near the Wasatch Fault. The 200-million-pound structure rests on massive stone foundations, making conventional underpinning impractical. The retrofit instead used closely spaced, incrementally installed steel casings beneath the foundations, which were connected to a structural frame and base-isolation system.<br /><br />The team excavated 16 feet around and inside the temple while maintaining support. Work included grouting and strengthening the existing foundations, installing exterior secant piles and interior micropiles, and tying the systems together with heavily stressed steel rods and walers. Difficult ground conditions, tight access, strict tolerances, and the need to protect the structure required careful sequencing. At the temple’s corners, crews hand-dug deep piers to create openings for construction access and future isolators. After the casings were installed, they were reinforced, concreted, and integrated with new foundations.

Keywords

Salt Lake Temple

earthquake retrofit

underpinning

base isolation

micropiles

historic masonry