Ironworker prepping rebar for poured concrete floor. This rebar infrastructure will form the support for the concrete floor. This high rise will eventually be 35 stories high; the picture was taken on the ninth floor.
Steel is recyclable, but civil engineering is working on ways to make it easier to repurpose.
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  • Sustainability is a growing topic in civil engineering because of the industry's carbon emissions.
  • There are new technologies and processes to help make construction more sustainable.
  • Challenges slowing down progress include complex materials and inconsistent research funding.

With the construction industry accounting for 38% of global energy-related carbon-dioxide emissions, a growing number of civil-engineering professionals are working toward making the industry more sustainable.

Civil engineering, which includes such disciplines as structural and environmental planning, is behind mostly everything that is designed, built, and maintained. Research and new technologies have resulted in new building materials and construction processes like 3D printing and modular fabrication. These are more energy-efficient and less wasteful and produce less pollution, while still maintaining structural integrity. But one expert told Insider many more solutions and government policies were needed to reach the larger sustainability goals recommended by the most recent report from Intergovernmental Panel on Climate Change.

At Northeastern University, professor Jerome F. Hajjar chairs the department of civil and environmental engineering. He said a useful way to think about how the shift to more sustainable engineering could be accelerated was by looking at the transition to buildings designed to better withstand or control damage from earthquakes.

Many of the changes in California were implemented through state building codes directed at reducing death and injury among new and existing buildings in the 1970s, '80s, and '90s.

"If we didn't do something about it, a lot of people were going to get hurt or die," he added.

Hajjar also oversees research on new design techniques like deconstruction, in which buildings are taken apart at the end of their lives and their components are reused rather than sent to landfills.

"We've developed structural systems for steel buildings that use various types of planks for the floor system that can be clamped to the top flange of a steel floor framing," he told Insider in reference to a method used to connect or attach objects. "But then they can be unclamped and the steel unbolted at the end of its useful life."

Structural steel produced in the US contains 93% recycled steel scrap on average, according to the American Institute of Steel Construction, but Hajjar said it still required a fair amount of energy to form new products.

"I think that being able to reuse and refabricate is one example of trying to cut down significantly on the amount of energy required for construction," he said.

Another challenge to making civil engineering more sustainable is the complexity of certain core construction materials, like concrete, which involves numerous materials in traditional and green formulations.

"We haven't found some miracle material that completely replaces these," he said.

It doesn't help that the vast majority of research funded in US is also focused on new construction and new types of systems. There is also the issue of the significant amounts of carbon-intensive construction continuing in countries like China and India.

One thing that makes Hajjar optimistic about the future is new programs like Northeastern's master's degree in sustainable building systems. Students come from backgrounds like architecture, civil engineering, environmental science, and public policy.

"They're so excited to get out into industry and help drive these issues forward," he said. "It's been really successful."

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