Empire Building Restoration – Building, ID

The Empire Building’s structure is a six-story timber frame with unreinforced masonry exterior walls. These walls are supported by steel columns and beams at the second floor, along Idaho and 10th streets, creating what is called a soft story. The structure basically had no resistance to lateral forces such as earthquakes and wind. Our goal was to design lateral force resisting elements that would not compromise the historical appearance of the Idaho and 10th street facades and also to be cost effective in our design. Our solution was to use the existing masonry as much as the code would allow resisting the lateral forces and then transferring those forces to new cast-in-place concrete moment frames from the second floor to the foundations along the Idaho and 10th street facades. These moment frames were designed to fit behind the existing narrow masonry piers.