GMS is proud to have collaborated on two projects that placed as finalists in this year’s Tall + Urban Innovation awards. 35XV (35 West 15h Street) was recognized in the Best Tall Building category; 56 Leonard Street was recognized in the Best Construction category. The CTBUH Awards recognize projects and individuals that have made extraordinary contributions to the advancement of tall buildings and the urban environment, and that achieve sustainability at the highest and broadest level. The objective of this awards program is to deliver a comprehensive and sophisticated view of these important buildings, while advocating for improvements in every aspect of their performance, especially those that have the greatest effect on the people who use these buildings each day. This often means that the buildings highlighted are often not the tallest in a given year, but represent the best qualities and innovations in the typology.

Rising 102 meters above a mid-block site, 35XV is a unique, hybrid residential-academic building located in Manhattan’s vibrant Chelsea neighborhood. Utilizing excess development rights from the historic Xavier High School, the building’s design artfully resolves a host of requirements, including the provision of needed expansion space for Xavier and the creation of highly crafted residential units that take advantage of their elevated location. The design further conforms to highly restrictive municipal bulk controls and is a “good neighbor” by relating to both the Xavier Campus and the surrounding streetscape, despite the project’s overall size.

As a result of an air-rights agreement with Xavier High School, 35XV employs a complex hybrid structure that allows for expansive, column-free spaces in the school’s portion of the building while the new condominiums cantilever 36 feet over Xavier’s property – a trendsetting example in the recent proliferation of cantilevered mixed-use buildings in Manhattan.

GMS provided consulting services for the facades and roofing of this 347-foot, 170,000 SF mixed-use building.

56 Leonard has been called the “Jenga” building due to its cantilevered floors, as well as the irregular spacing and location of the balconies throughout its 57 stories. Above the fifth floor, there is a 6-meter cantilever to the west and a 4.6-meter cantilever to the south, both of which were constructed over occupied New York Law School buildings.

To build the superstructure safely, emphasis was placed on designing a custom, stackable perimeter screen system that provided full, passive fall protection. From the 45th floor up, all formwork and shoring, falsework, etc. had to remain in place to provide the necessary structural support to form and cast the floors above. The system was engineered so that once the concrete on the roof was cured, stripping could proceed from the top down until it concluded on the 45th-floor platform. With an average floor-to-floor height of 2.7 meters, the use of heavy-duty 10k shoring towers was required.

GMS provided Quality Control inspections for the architecturally exposed concrete portions of the building as well as QA/QC formwork inspections.