By: Paul Rosta, Senior Associate Editor
For many buildings, glass makes up the most striking and visible part of a structure’s exterior. And as owners and tenants in office buildings and other property types seek attractive views, energy efficiency and security, glass engineering and design is taking center stage.
Although the role of glass is well established in building design, innovations are also changing the role of glass and providing developers with more options. “From an engineering point of view, we have more and more architects coming to us using unique solutions with glass,” said Richard Tomasetti, chairman of Thornton Tomasetti Inc., a renowned New York City-based engineering firm. Tomasetti spoke to CPN Thursday, a day before he was scheduled to moderate a panel this morning during a symposium on engineering glass at the Columbia University Graduate School of Architecture, Planning and Preservation in Manhattan.
One of the biggest changes that may surprise even seasoned developers is that glass is increasingly pulling its weight when it comes to holding itself up. As Tomasetti explained, “The glass is doing more work as a structural element, and taking more of the stresses and strains than it did.” Engineering strategies range from a tennis racket-like system of cables that holds the panels in a grid to glass mullions or gaskets that grab panels at the corners.
As a result of these innovations, Tomasetti believes that glass design is evolving more toward lighter weight and minimal support structures. Future projects will continue to build on recent examples like the Midtown Ferry Terminal, a $56 million project that opened two years ago on the Hudson River in Manhattan. For that project, Thornton Tomasetti designed a framework of structural steel tube that used finger-like elements to grab glass panels at the corners.
Whatever the method may be, the goal is to reduce the weight of the curtain wall and the need for elements that hold glass panels together. To rebuild the Winter Garden, the public space at the World Financial Center that was severely damaged in the 2001 terrorist assault on the World Trade Center, Thornton Tomasetti developed a support system of glass mullions to enhance visibility.
Going forward, sustainability goals will help drive the frontiers of glass technology, noted Jeffrey Ng, an architect and vice president for Thornton Tomasetti who advises clients on curtainwall strategies. One leading trend is the use of triple-coated panels that significant cut down on the level of heat entering a building by reflecting infrared light. The coatings and tinted glass also slightly reduce the amount of light and can command a premium of a few dollars per square foot for the panels, but can also result in big long-term energy savings, he said. Another promising technology uses a laminate to transform a glass curtainwall panel into a photovoltaic cell. Ng cited the example of a commercial building under construction in Guangzhou, China.
