BIM in the Big Apple

The 8 Spruce Street skyscraper, designed by architect Frank Gehry, now stands as one of the most distinctive features of the Manhattan skyline. The 1.1 million-square-foot building (originally known as Beekman Tower and currently marketed as “New York by Gehry”) is predominantly residential, although the lower stories house a city public school and office space for the New York Downtown Hospital. Measuring at 870 feet in height, the tower is the tallest of its kind in North America. 

The skyscraper and its unique façade were designed and constructed using building information modeling (BIM). During design and construction, Gehry Technologies (GT) provided BIM infrastructure and supply chain management services, which included the development of a 3-D building model containing critical construction information that enabled a more automated design-to-fabrication process. The project is a prime example of how BIM is revolutionizing the building industry and how new, innovative solutions can achieve cost-effective project outcomes with higher quality and more value. 

Controlling Costs

The tower’s façade gives each floor of the 76-story tower a unique configuration. Gehry designed the tower to accommodate the owner’s request for bay windows in each unit. Instead of aligning the bay windows vertically, he moved them slightly from floor to floor and adjusted their sizes from unit to unit, causing “wrinkles in the building’s skin.” Seven sides of the T-shaped tower have this configuration, while the south side of the tower (the top of the T) is a flat plane. 

The project team employed several key strategies to economically deliver this unique building skin, including a mix of conventional and unconventional geometry realized through the mass customization and modular prefabrication of the curtain wall panels. 

At first glance, the entire curtain wall appears to curve and fold. The wall actually combines conventional flat curtain wall systems, slightly curved systems and highly shaped systems that cantilever up to 6 feet to create a pronounced wrinkle effect. To control fabrication and installation costs, the stainless-steel sheets are riveted to conventional rain screen subframes. The frames, in turn, attach to flat, unitized curtain wall panels, forming sections almost 10 feet tall and varying in width from 3 ½ to 5 ½ feet. 

All of the modular units were fabricated offsite, avoiding the higher costs of onsite staging. During installation at the jobsite, more than 10,000 of these shop-fabricated panel assemblies were hung from the cast-in-place concrete floor slabs on aluminum embeds. 

Throughout the design process, GT’s 3-D building model provided a platform for close collaboration between the owner (Forest City Ratner), the architect (Gehry Partners) and the curtain wall fabricator (Permasteelisa). The digital connection from design to virtual construction allowed the team to continually visualize and price the curtain wall system during its design, to better inform their decision-making. 

Get with the Program

Due to the building’s distinctive shape, the façade’s design depended on the organization of the residential units. In an effort to capitalize on real estate market fluctuations, the owner studied different configurations of the building program—from the initial plan of condominium units to the final mixture of rental units. Every programmatic change would subtly impact the proportions of the façade, which, in turn, caused the whole undulating surface to change.

These programmatic changes produced more than 100 different versions of the building model, a dozen of which progressed all the way to final shop drawings. Reconciling the owner’s changing program requirements with the cost of the curtain wall fabrication posed one of the main challenges to both the design process and the project’s overall budget. 

GT used their rule-based parametric BIM software to model the complicated building surface and tie that model to Permasteelisa’s pricing for the range of panel types used on the project. For each program change, GT used the BIM software in combination with this recipe of different panel types and pricing. Mixing and matching the components allowed the project team to hit the owner’s pricing goal. The data gleaned from the software gave Gehry and the owner dynamic feedback on the program tweaks from both a cost and aesthetic point of view. 

On-Demand Project Collaboration

The project team also used a web-based file management and BIM collaboration platform that helped the team communicate, share and synchronize project information virtually. The extended project team exchanged project information with individual team members over the Internet, no matter their location or time zone. 

This BIM collaboration platform also allowed the team to view a variety of 3-D models and perform clash detection for project coordination. Because the software supports a wide range of model types, the array of software packages used by the different building design disciplines and subcontractors on the project did not present a challenge.

Streamline Design-to-Fabrication

As the project progressed, the 3D modeling software was instrumental in the fabrication of the curtain wall panels. Permasteelisa had used the model’s dimensions and geometries to price the curtain wall units while the design was being finalized. During fabrication, the firm used that same building model and information to automate its production—downloading geometry for each panel to produce CNC data and drive the manufacturing process. 

The precise nature of the model also enabled the team to exactly model and coordinate all the concrete slab edges and the fixtures required for installation, including approximately 14,000 aluminum brackets embedded in the slabs from which the curtain wall panels would hang.

The Bottom Line

By the time the tower opened, the owner considered the project a complete success. The close collaboration stemming from digital design and construction processes resulted in almost no errors, comparable costs and a very low number of RFIs—just 200 versus the standard 5,000 that is typical for a project of this size. The project owner was left with a powerful as-built model that could be used for marketing visualizations, build-out, commissioning, handover and ultimately, operations.

BIM processes produced a knowledge-driven, design-to-fabrication connection, and the collaboration platform enabled a more dynamic, interconnected approach to project communication and broadened the flow of information. The project team reached a consensus faster, made better decisions and improved project delivery.