The project consisted of two objectives, a 41,000 square foot building expansion and an existing infrastructure upgrade. The building expansion was immediately north of the existing Amundson Hall, which is located along Washington Avenue on the University of Minnesota East Bank Campus.
University of Minnesota - Amundson Hall Gore Annex
Location: Minneapolis, MN
Square Feet: 41,000 Addition
Construction Materials: Cast-in-Place Concrete, Structural Steel, Post-Tensioned Concrete, Light Gauge
Awards and Recognition: Grand Award - American Consulting Engineers Council of Minnesota
The University of Minnesota Amundson Hall Gore Annex Addition included a six-story addition - four above grade and two below - with a mechanical penthouse and infrastructure upgrades throughout. The project was located on a very tight site which was further complicated by the need for the addition to extend 11 feet below the adjacent building.
Due to the depth of the new addition relative to the adjacent building, the existing footings were underpinned and a temporary soil retention system was required until a permanent cast-in-place wall could be constructed to provide permanent soil retention approximately five feet north of the existing foundations.
To limit floor-to-floor heights that were dictated by the existing structure, the structure of the addition was constructed with two-way concrete flat plate floors supported by concrete columns. The most prominent architectural feature of the addition is a three-story diagonal concrete brace that supports three floors of a 22-foot cantilever. This concrete brace was to remain visible from both the exterior and interior, so it was constructed of post-tensioned steel rods combined with traditional mild steel reinforcing to minimize unsightly cracking in the concrete. To control the initial deflection of this cantilever due to the large overall self-weight in the brace itself, the post-tensioned rods in the brace were stressed in two stages.
Along with the new addition, the existing curtainwall system along Washington Avenue was replaced with a prominent new system to replace the dated glazing. New curtainwall connections were designed and detailed since the existing vertical mullions also doubled as the existing building columns. The result is an attractive, energy efficient facade that makes the existing 60-year old building look new again.