Rebar robot ties steel for fast construction

A US start-up has invented a robot that can tie together steel reinforcement bars before a concrete pour, saving many back-breaking hours on bridge and other construction projects.

The machine, called the Tybot, uses a robotic arm rigged to a gantry crane that locates rebar junctions and attaches a tie.

Since deck bridges and other structures can have thousands of such intersections, the robot could circumvent a labour-intensive, expensive and injury-prone process – although one of its inventors joked that it was “boring”.

It is the first offering of the firm Advanced Construction Robotics (ACR), launched by construction firm boss Steve Muck and robotics expert Jeremy Searock, formerly of Carnegie Mellon University’s National Robotics Engineering Centre.

“What we’re trying to do at ACR is methodically look at the most difficult critical path challenges, and our first product reflects that, because one of our big challenge is finding people to tie deck rebar,” said Muck, who has experience of building bridges as chief executive of Pennsylvania contractor Brayman Construction, of which ACR is a spin-off.

Muck told the Pittsburg Post-Gazette that when his company, Brayman, built the Hulton Bridge in 2015 it took a crew of up to 10 workers 7,400 man hours between April and September to lay 113,000 square feet of rebar, tying just over 2 million joints. 

“[Tybot] both speeds up the work and reduces the number of people to do it,” Muck told the newspaper. “This is the construction industry looking to the robotics industry for a solution to a business problem.”

He added that Tybot tie rebar at night or when workers are needed elsewhere.

Academic Jeremy Searock told the paper: “This is a very boring robot that has great application and profitability.”

Elsewhere, Searock said that although the robot requires a frame, it is still convenient to set up. “It’s easy to integrate into operations. You can transport it to the project in a 40ft trailer, it takes half a shift to set up, it can deal with decks between 20ft and 145ft wide using the infrastructure already on the bridge.” 

Once the robot is in position it can operate autonomously with one worker supervising.

Brayman tested the Tybot on a project in Pennsylvania earlier this year and now plans to begin selling its product next spring.

Image: The robot arm has sensors to detect junctions and a gantry crane for mobility (ACR)

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  1. 1) Can it cope with extra bars in areas of high hogging moment.
    2) It seems to be leaving the loose ends of the ties sticking up. This is bad practice as it means you do not achieve the specified cover.

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