Brought to you with support fromA nearly 1,000-foot, mixed-use tower was recently completed in Guangzhou, the third largest Chinese city behind Beijing and Shanghai, about 75 miles northwest of Hong Kong. This is the third project that Chinese-based R&F Properties has developed with Chicago-based architect Goettsch Partners. The building, named R&F Yingkai Square, benefits from a masterplan that is almost fully realized—to date— and involves planned gardens, cultural space, museums, and mixed-use towers. Paul De Santis, principal of Goettsch Partners, said the Pearl River area of Guangzhou was envisioned 15 to 20 years ago, and is nearly complete today. “In China, the context often changes too rapidly to formally respond, but the government was very committed to this particular master plan. It gave us an opportunity to be contextually sensitive." Angular canted corner walls break up the massing of the otherwise boxy tower, providing specific views out into the city. While the northwest corner provides good views 250 feet above neighboring buildings, the northeast corner is best viewed only 100-feet high. This led to a “syncopation,” as De Santis called it, in the location of the 8- to 10-story chamfered corners. He said other view corridors into the cityscape can improve or get worse depending on height. "We use the corner carves to not only architecturally call out the mixed use stacking of the building but also highlight those signature moments." A nearly 14-foot-high reinforced concrete floor-to-floor spacing accommodates a 10-foot clear ceiling. The exterior wall is a unitized curtain wall system. Operable ventilation for occupant comfort is incorporated into the system. The glass is an insulated low-e assembly with an aluminum mullion system. A lot of energy was put into the detailing of the corner units, which are also unitized, but consist of three layers of laminated fritted glazing for added structural and aesthetic benefits. To address both daytime and nighttime lighting conditions, the frit is two-sided: white on the outside, dark on the inside. At nighttime, the glass can be "grazed" by LED's which allows for the building to be illuminated to the exterior without introducing light to the interior space. During the day, the dark frit from the interior is nearly imperceptible when looking outward to the exterior. A gradient of panelized stainless steel panels tapers into the curtain wall glazing. The architects say this composition is an expression of the gravitational quality of the tower and a response to the stacked program of the building. By utilizing opaque panels at the base of the tower, the shell of the building is responsive to a connective infrastructure of bridges and tunnels tapping into the building to support retail use. With office and hotel uses above, the panels give way to transparent view glass. The bulk of the building is dedicated to office use, organized into four zones. Situated within the office is a "sky lobby" for the office users. The Park Hyatt occupies nine floors above the offices, and the tower is capped off with hotel amenities such as a pool, lobby, lounges, three restaurants, and an outdoor terrace 300m off the ground. As stainless panels taper in width, their height and vertical spacing remains constant. Horizontal coursings slightly overlap at spandrel panels, which assume a unique, but repetitive, geometry. The composition allows for a more standardized view glass unit on each floor and De Santis assures us on the logic behind the facades panelization: "It looks more complicated visually than it actually is." One primary dimensional restraint was set by the glass manufacturer who limited a panel width to 600 mm, or around 24 inches, due to manufacturing processes. The final massing of the building was designed iteratively by incorporating a rigorous approach to wall modulation, accommodating glass manufacturing dimensional requirements to produce a "final" geometry of chamfered corners. The architects integrated lighting into the facade assembly in response to what they consider a cultural norm in tall Chinese construction projects. De Santis said, “Our number one goal was to try to manage light pollution—a serious issue in the city.” To combat this, the architects located LEDs behind stainless steel panels which cant outward as they taper up the building into thin vertical strips. This provides a subtle indirect lighting element without exposing the source. The architects went with this approach to avoid having to flood light or uplight the tower with harsh lighting. The LED's are programmable and can be syncopated, change colors, and dim to produce effects ranging from static to theatrical. De Santis says the ability of this project to cater to both a pedestrian and urban scale is particularly successful, and a good learning lesson for future tower projects. "The sense of intimacy we were able to achieve for the arrival sequence of the hotel. 300-meter (984-foot) tall towers have a big impact on your surroundings, and to get a level of intimacy means that you are able to incorporate an interesting level of detail and material selections. The feel of the space is anything but cold and austere, which is often the case in large tower buildings." De Santis explains the Hyatt hotel brand prides itself on this level of intimacy. “It's less about grand ballrooms and lobby spaces, and more about producing warmth and a human scale.” This triggered a change of material at the hotel drop off point. A dark anodized steel and Chinese screens in the ceiling pair with a simple natural stone that washes the entire space in a natural, light-toned coloration. This provides a backdrop for sculptural artwork and provides the basis for unique multi-story spaces "carved" into the tower in the upper floor lobby and lounge spaces. De Santis concludes, “Your tower can have an expression. You can create an intimate environment without losing the expression of its urban gesture."