Honorable Mention: Municipal Category
Ogden Municipal Building
Submitted by Sika Corporation
The Ogden, Utah, Municipal Building was built in the early 1930s in the “modern progressive” style of art deco. Because of its importance to the community of Ogden and in order to continue to preserve the uniqueness of this style, a complete seismic renovation of this historic landmark was conducted by a consulting engineer.
A computer analysis demonstrated a tendency of the upper section of the building to whiplash during an earthquake. The structural upgrade would include a combination of an added steel frame and composite wrapping of columns and pan joists.
A specially designed steel frame was lowered through the roof and floors to stiffen the structure. The interior columns were wrapped with two layers of glass fiber fabric, to confine them and add ductility. The interior pan joists were wrapped with two layers of a carbon fiber fabric to add flexural strength, then wrapped with two more layers of glass fabric to add shear strength. This composite retrofit was critical to maintaining the aesthetic value of this building. The carbon and glass fabrics offer exceptionally high strengths–five times stronger than steel. The fabrics were applied with negligible change to profiles. As a result, the building was stiffened, yet the fix is virtually invisible.