Detroit's $3.5 Billion Bridge to the Future

Local truck traffic in Detroit will double by 2035, and those trucks will be crossing a new bridge. Approved for construction in 2012, the span will link Detroit to Windsor, Canada. It will also be a symbol of city reborn.

Read more: Detroit's $3.5 Billion Bridge to the Future - Detroit 2025

30-story high-rise built in 15 days

Broad Sustainable Building built a 30-story high-rise in 15 days. That's bold: In 360 hours the company threw up a hotel with 350 guest rooms, plus amenities including a swimming pool and a helipad. BSB made plenty of waves with its construction process—basically a modular design stacked one story right on top of the next. But the company plans to make even more noise next year by building the world's tallest structure—220-story Sky City tower—in a mere 90 days.

Gray to Green: How to Make Cleaner Concrete

Because it's cheap and strong, concrete is one of the most widely used construction materials in the world—people use about 6 billion tons of it every year. But for every cubic meter of concrete that's poured, as much as 1050 pounds of carbon dioxide is released into the atmosphere. Here's how some people are trying to make concrete more environmentally friendly.

Read More: Gray to Green: How to Make Cleaner Concrete

Safety Snake: The Construction Worker's New Best Friend?

Inspecting high-rise construction sites is a dangerous job, but somebody--or some robot--has to do it. Engineers at Virginia Tech built the HyDRAS-Ascent II to climb by encircling a beam and twisting its 90-degree joints in sequence. In December, the robot won the grand prize at the Capstone Design Fair in Seoul, South Korea, competing against experimental robots, electronic gizmos and other novel hardware. 

Smart Design and Super Materials Are Stretching Bridges

Suspension bridges like the Golden Gate get all the glory, but these landmark structures are expensive. New advances are allowing cheaper, cable-stayed bridges to cover longer spans.

Read more: Popular Mechanics 

10 of the Biggest Boldest Builds of 2012

From staggeringly large bridges to stadiums to towers, 2012 was a year of grand designs.

Read more:  Popular Mechanics