Utah State Capitol

Few projects garner the deserved attention of the historic Utah State Capitol Restoration.  Originally constructed in 1915, the 320,000 square foot Utah State Capitol needed to undergo a complete restoration and renovation in order to ensure public safety in the event of a major seismic event.   Th project was highlighted by a complex base-isolation system that features 265 base isolators and 15 sliders that were installed under 280 of the 380 concrete columns that support the building.   This state-of-the art design strategy essentially de-couples a building from the ground, which in turn limits the potentially catastrophic effects of horizontal earthquake ground motions.   Before crews could begin installing the base isolators, soil at the site was reinforced with an extensive micropile suspension system called the Titan Hollow Bar system.   At the Capitol site, approximately 3,000 individual micopiles were drilled up to 30 feet into the ground and reinforced with a water-cement mixture that combines with sand and gravel to form a 3,000 to 4,000 psi concrete shell around each micropile.