Envisioning a new way of sustainable design

The final cast-aluminum model of Edward Segal and his team’s City of Dreams project on Governor's Island.  // Photo courtesy of Josh Draper, Lisa Ramsburg and Max Dowd..

A recent design project showcased unconventional ways to practice engineering; Hofstra University’s Provost: Spring 2022 Distinguished Faculty Lecture was presented by Edward Segal, assistant professor of engineering, on Wednesday, April 13. Segal’s lecture was called “Building in Unconventional Ways with Novel Design-to-Fabrication Methods,” and he proposed that engineers should consider materials that offer environmental, economic and social advantages. 

Segal discussed the role of sustainability in the design, fabrication and installation of the structure his team created for the 2017 City of Dreams design competition. The competition aimed to imagine “what sustainability is for New York and how moving forward we could incorporate more sustainable features in our infrastructure,” stated Segal. 

“The idea we proposed was to take wet clay, allow it to dry and crack, take aluminum, like aluminum cans, melt them down, pour them into the cracks of the clay and take the resulting panels and form structures with them,” Segal said. 

The project's goal was to create new products from recycled materials, according to Segal. 

Using recycled products as unconventional materials has been a popular idea in the engineering field due to the environmental advantages of sustainable infrastructure. However, Segal proposed pairing this with unconventional construction methods in order to transform recycled products into new ones instead of regularly using these materials in their initial form.

“Cast and place utilized the natural process of clay cracking,” Segal said. “ [Essentially] casting with clay has the potential to be less energy-intensive than casting with more traditional resin bonded sand.” 

As further developments are made regarding the design and fabrication of projects, Segal asked the audience to consider, ”What other natural phenomenon can we utilize to generate new structures?”

Gravity could be used to create arches due to the natural tension in structures, according to Segal. 

In a recent project for the International Association for Shell and Spatial Structures, Segal and his team invested in a “full-scale flip idea” where they explored how to incorporate plastic into the design. 

“We can pin fabric. We can hang the fabric, and we can flip it,” Segal said. 

Segal and his team designed acrylic panels that were discretized, combined to form a flat panel and transformed by ”heating it past the glass transition temperature to become stretchy.” This resulted in an arched structure that was flipped over so people could walk below the structure. 

Before the finalized acrylic structure, Segal’s team fabricated and tested multiple prototypes, causing him to consider more efficient ways of implementing small-scale prototyping with the help of a 3D pen. 

A student who collaborated with Segal on testing the efficiency of 3D printing pens explained the process.

“3D printing pens allow for the rapid generation of small-scale models [that] are easy to operate and encourage free form design of 3D printers in combination with modeling software,” said Lillian Moy, a sophomore civil engineering major. “Students and practitioners may use this method to prototype a grid design, hang and heat the grid in the oven, flip the structure and analyze its efficiency.”

Segal also noted the importance of hanging and heating 3D printed bioplastics. One student, who collaborated with Segal on her own 3D printed hanging structure titled Resilient, explained how the project came into existence. 

“It was a very intriguing topic to me because a question that I always ask myself and Dr. Segal is: ’Why are all the structures we see around us made of concrete and steel?’" said Esther Zhang, a senior civil engineering major. “[Concrete and steel are] very practical and strong materials to build with, but they're also terrible for the environment because of all the carbon that gets released in their production.”

Rendering proposal from Dr. Segal’s team utilizing barriers to create a structure in Buffalo. // Photo courtesy of Albert Chao.

Another sustainable design idea that Segal has is to reuse the plastic barriers in Hofstra classes to create an overhead roof structure for a small greenhouse. The barriers are made of acrylic or polycarbonate and are not well established recycling streams for these materials, according to Segal. 

“We don’t have to keep creating the same things that we’ve seen out in the environment,” Segal said. “We don’t have to keep using the same materials. We can keep experimenting.”