The design constraints, as outlined in the PNF.
The placement and footprint of the tower has been driven primarily by the open space requirements and guidelines of the DWMHP, most particularly the mandate to preserve 50% of the Project Site as open space. A large public plaza was created along Milk Street by allocating 30% of the open space to the north. This grand plaza along historic Central Wharf will create a new East-West pedestrian connection between the Greenway and the water, and is a key component for the full realization of the proposed Blueway vision.
The tower footprint was limited to 50% of the Site and designed to maximize public spaces along Central Wharf to the north and along the Harborwalk to the east, while locating 10% of the open space on the Project’s south side for additional separation from the adjacent Harbor Towers residences for privacy and views. Careful thought was given to the placement of ground floor lobbies and ramps to best meet the needs of building occupants, respect concerns of the City and neighboring properties, and enhance the public experience. Retail frontage has been maximized to create a vibrant street wall along three sides of the Site.
In response to the DWMHP requirement limiting shadow fall on Long Wharf, the tower form took on a stepped language, with the mass reducing through a series of setbacks as the building ascends. In addition to reducing the shadow fall, these setbacks also break down the scale of the tower, relate to heights of neighboring buildings, improve wind mitigation, provide outdoor spaces to building occupants, and open view corridors for neighboring Harbor Towers residences.
The resulting form is an extruded geometry, where volumes peel apart from one another and stepback as the tower rises, creating a stepped expression that is wider at the base and narrow at the top (Figure 2-22). The tower shape reflects the program within, starting with retail at the base, (Figure 2-23 to Figure 2-26) followed by a series of setbacks up the height of the tower that reduce the floor plate size for proper leasing depths through the office portion, and continuing to the upper portion with the smallest floor plate for residential units where shallower depths are desired. Each of the setbacks creates exterior terraces that are accessible to the building occupants.
The stepped form becomes a unique and powerful image on the skyline while being respectful of the existing context (Figure 2-27). Another strategy that was used to reduce the shadow impacts was a rounding of the overall form of the tower into a clover-like plan. This also had the added benefits of easing pedestrian flow around the base of the building by creating smooth circulation paths (Figure 2-28) and opening up view corridors to the water (Figure 2-29). The rounded form was given a more refined expression by folding the façade in and out along the perimeter of the tower. The folded expression of the façade enhances the verticality of the tower, which is further emphasized by treating one side of the fold as a solid panel, creating vertical bands. As well as improving the appearance of the tower, the folded language acts to mitigate wind as it travels around the tower, and reduces any potential impacts of solar glare by scattering and diffusing light reflections, rather than allowing them to focus on one point. The façade is based on a plan module of approximately seven feet of glass and three feet of solid, with the solid portion expressed as a metal or terra cotta panel.
Building footprint on lot: About 28,000 sq ft
Below grade parking, six levels: 1,100 spaces, about 433,000 sq ft
Base: 40 feet, two floors of retail / amenity space, 42,000 sq ft.
Office: 320 feet, 22 floors, 538,000 gsf, average about 24,500 sq ft per floor
Residential: 225 feet, 18 floors, 284,600 gsf, average about 15,800 sq ft per floor
Roof mechanicals: 15 feet
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A straight-forward, rectangular-box alternative:
Building footprint 28,000 sq ft
32 floors
Building's gross square feet: 896,000
Height 416 feet: 32 floors, @ average 13 feet height floor to floor