When Superstorm Sandy toppled a tower crane working at a high-rise building in midtown Manhattan this fall, engineers immediately began searching for clues to ensure the site was safe. Within days, the partially collapsed crane was secure, and workers began a delicate process of removing the steel wreckage. The job is still in the recovery phase.
The cause of the so-called dangling crane is believed to be an "act of God," Peter Stroh, who engineered the crane's connections to the building, recently told ENR. Below is a summary of this story and others about heavy equipment and materials that made headlines this year.
ENR and its sister publication, Architectural Record, broke the news that the partial crane collapse was at risk of falling into the streets below, creating a potentially dangerous situation.
Forensic engineers who descended on the crane-accident scene in Manhattan concluded early on that the dangling tower crane was properly secured prior to the storm. Operators typically "weather-vane" a tower crane when not in use, and this machine was no exception, ENR reported. Wind gusts and vortices acting on the building and the crane likely led to the machine's jib flipping over backward, experts said.
ENR later reported how engineers worked with the city's buildings department to secure the dangling tower crane so the city could lift a standing evacuation order. The story exposed the heroism on the part of the city's building inspectors, including Assistant Commissioner Michael Alacha, who led a party of investigators to the top of the building during the storm to inspect the crane's mangled steel.
"I think Mike Alacha handled the situation very well," said Stroh. "He kept a very calm head."
Get a Grip
A joint project between General Motors and NASA, the Robo-Glove could make construction work less of a pain while giving tradespeople a bionic grip, ENR reported earlier this year.
Still in the testing phase, the device initially was conceived for work in the manufacturing and aeronautics sectors. However, people involved in the project tell ENR that construction would be an ideal application, as well.
One of our most popular equipment stories this year was an exhaustive report on supersized cranes, which can lift loads in excess of 2,000 tons.
Increasing in demand due to the rise of modular construction, a resurgence in nuclear power and the need to lift large building components over existing infrastructure, supercranes require a lot of jobsite engineering that is far more complicated than planning a routine lift.
ENR's review of the supercrane trend included dramatic photos of these massive machines, as well as detailed charts ranking the top cranes around the world by maximum capacity and practical lifting radii.
Dwindling construction jobs, tight credit and cash-flow restrictions have created an ideal environment for contractors to buy less equipment and rent more. It came as little surprise, then, that two of the world's largest rental companies, United Rentals and RSC, decided to merge to leverage their geographic footprint, resources and buying power.
Rental companies have grown during the recession, buying up more than 50% of all new equipment sold this year. Earlier this year, ENR provided a deep dive into the $4.2-billion United-RSC merger, which closed on April 30, and illustrated why rental has become a force in the heavy-equipment marketplace.