Researchers from the Massachusetts Institute of Technology are demonstrating how bridges could be built using significantly less material.
According to MIT News, the production of construction materials accounts for more than 7% of global carbon emissions. Researchers say that figure could be reduced through a technique known as topology optimization.
Topology optimization is a computer-based engineering design tool that determines the most efficient way to distribute material within a defined space while meeting a project’s structural requirements.
While the technique has primarily been used in research and 3D printing because of the complexity of its designs, MIT researchers have developed a framework that makes topology-optimized structures easier to construct at larger scales, such as bridges.
The framework allows engineers to apply practical constraints to algorithm-generated designs, including limiting how many structural components connect at a joint and setting minimum sizes for structural members, according to MIT News.
Making Optimized Designs Easier to Build
The research team designed steel, wood and hybrid truss structures for bridges and buildings, demonstrating that carbon emissions varied significantly depending on the design constraints and material combinations.
Their goal is to make computer-generated topology optimization designs more practical for engineers by simplifying their outputs without sacrificing structural performance.
Researchers incorporated a class of equations known as “mixed integer algorithms” to make yes-no decisions throughout the design process, including material selection and connection layouts. The algorithms also account for material properties—for example, recognizing that steel struts can carry compressive loads while steel cables cannot.
Users can increase or decrease design complexity by setting limits on the number of connections at each joint, specifying minimum angles between connected members and establishing minimum component sizes.
To demonstrate the framework’s real-world applications, researchers redesigned the Upside-Down Bridge near Buffalo. Applying different design constraints produced what MIT News described as “dramatic differences” in the resulting truss configurations, fundamentally changing how each bridge would be constructed.
The team also generated wood-only, steel-only and hybrid wood-and-steel designs to compare how different material combinations affect constructability and environmental impact.
Although topography optimization is computationally intensive, researchers were able to run the programs on a standard MacBook Pro and believe the technology is practical for use by many civil engineering firms, MIT News reported.
Source: MIT News
