Grant High School Renovation and Modernization

The complete renovation and modernization of Grant High School included three buildings: the old 1923 gymnasium, a new gymnasium, and the historic main wing (Type III-B, Type II-B, and Type I-A, respectively). The KPFF team worked closely with the owner, architect, and contractors to develop a practical strengthening scheme.

KPFF provided seismic strengthening design, utilizing ASCE 41 to determine the existing building capacity and strengthening requirements. Seismic load was collected via structural steel diaphragm collectors into new reinforced concrete shear walls and delivered to the soil by spread footings. The walls and footings were tied integrally with the existing structure.

The historic main wing, which consisted of five buildings that had been tied together as one, largely consisted of non-ductile concrete construction with pan joist slabs. KPFF took an innovative approach by calculating the capacity of the existing pan joist slab to avoid diaphragm strengthening, which consisted of considering the welded wire mesh in the slab as well as the continuous bent reinforcement bar in the joist. Collaborating closely with the contractor, the engineers used ASTM A722 Grade 150 bars for collector steel to facilitate placement instead of conventional Grade 60 rebar.

The old gymnasium consisted of unreinforced masonry with wood diaphragms. New concrete shear walls, collectors and footings were also used in this building as well as wood diaphragm strengthening at the roof. The tall gymnasium area was transformed into a two-story arts wing with exposed roof trusses on the second floor.

The team completed the project within a strict construction time frame that accommodated the school year, the school district’s limited swing space, and other planned renovations. KPFF quickly reacted to field conditions throughout the project duration to keep the project on schedule.