Hale Kalele is a public-private partnership to transform a State-owned, underutilized urban parcel into a mixed-use development featuring a 20-story affordable rental tower, two-story Juvenile Center, and six-level parking structure. To support the project’s long-term needs durability of the tower and its units was of utmost consideration, so an all-reinforced concrete system utilizing tunnel-form construction was selected.

The developer Kobayashi Group wanted to be mindful of the project’s carbon footprint and with the design and construction team, the use of CarbonCure was selected. CarbonCure uses clean technology to create concrete with less cement, resulting in a reduced carbon footprint without comprising strength. Since this would be the tallest building to date utilizing CarbonCure, the project team and the concrete supplier implemented a stepped process in its incorporation in the concrete mixes. This included progressively increasing the amount of CO2 injection while decreasing the amount of the cement in the mixes as the tower went vertical. Additional concrete testing was performed by BASE and the concrete supplier to help track the progress and allow for further reduction of cement content. By the time the typical tower floors were reached, there was enough data to justify the proposed final mix and the project was able to achieve a 5% reduction in the cement requirements. The success of Hale Kalele has now become a model for other concrete buildings, small and tall, to reduce their embodied carbon.

In addition to being structural engineer of record, BASE also provided building code-required special inspections and material testing services. This allowed for seamless coordination between the design and construction of the primary structures. BASE also provided contractor support services such as design of tower crane and man hoist foundations with tie back connections and material loading platforms.