Cranes are an essential part of many large construction projects. They allow for the movement of material and equipment to areas otherwise out of reach. Unfortunately, the basic technology underlying crane operation has not changed much in recent years, and it may be costing workers their safety.
"Cranes are perhaps the most dangerous piece of equipment on a work site."
Given their utility in the construction of high-rise towers, cranes often operate in dense urban areas where space must be carefully navigated. Despite these constraints, crane operators are typically guided by little more than voice commands over radio and whatever they may be able to see themselves. These challenging conditions have given cranes the dubious distinction of being perhaps the most dangerous piece of equipment on a work site. According to a study into crane fatalities by the Center for Construction Research and Training (CPWR), 632 workers were killed in a construction crane-related incident between 1992 and 2006, an average of 42 deaths per year.
New attention was drawn to construction crane safety following a streak of deadly accidents within a 10 week period in 2008. In this small amount of time, three crane accidents (two in New York City and one in Miami) took the lives of 10 workers and one bystander, The New York Times and CBS News reported.
These events, as well as the sobering statistics cited previously, have provided the impetus for innovation in crane design and operation to increase safety and effectiveness. A team of researchers from both Penn State and the University of Illinois at Urbana-Champaign was recently awarded a $650,000 grant from the National Science Foundation with the goal of improving the operating technology of construction equipment. While the team will initially focus on cranes, they hope to extend these systems to the full fleet of construction safety systems found on a work site.
The latest data available on crane accidents and fatalities points to persistent difficulties in controlling cranes in a constantly changing environment like a construction site. In their analysis of available data, CPWR identified three common causes of crane-related fatalities: power line electrocutions, struck by crane deaths and collapses. Electrocution leads the causes of death with 25 percent of all crane-related fatalities being attributed to this. Another 21 percent were from being struck by equipment carried on a crane, a significant change from previous studies. Both of these two leading causes of death from construction cranes testify to the inherent risk of navigating a crane in a crowded environment without adequate planning and supervision. While construction laborers accounted for the largest share of deaths caused by cranes, they also posed a significant risk to bystanders.
In their analysis and recommendations based on these data, CPWR noted a lack of adequate training, planning and supervision of crane operations as a common thread in these accidents. The NSF grant to Penn State and University of Illinois researchers aims to solve at least part of this equation by bringing crane operations into the 21st century. According to a release acknowledging the grant award, the team, led by architectural engineering professor Chimay Anumba, "[plans] to develop a system for construction equipment that combines cyber and physical components that will interact for maximum effectiveness." This includes omnidirectional cameras and data-collecting sensors that will allow crane operators and supervisors to monitor several aspects of a lift all at once.
"One thing that makes a site unsafe is that constantly changing and dynamic environments can create problems," Anumba explained. "For instance, traffic flows change as the work goes on. Providing equipment operators with updates in real time will have huge safety implications."
"Researchers hope to combine visual and haptic cues in their crane control system."
Specifically, the research team hopes to improve the process of the "blind lift," perhaps the most dangerous operation undertaken by operators of construction cranes. In essence, the maneuver is exactly as it sounds: the crane operator is unable to see the object being lifted. This means the operator has only verbal instructions from ground workers as input for guiding the object to its destination, which can spell disaster without perfect coordination. Anumba's team has proposed a system of cameras that utilize 3D models of the crane's surroundings, as well as "haptic cues" that would allow the operator to physically feel feedback if the object is off course.
"By integrating cameras with the virtual model of the environment, the operator can have a much better understanding of what they are lifting in relation to other physical components on site such as workers, other equipment, materials, and power lines," Anumba said.
The grant, which will begin Jan. 1, 2016, will last three years and concentrate on mobile cranes, which are statistically more prone to accidents than other types of cranes. Anumba and his team hope the project goes well enough to extend the technology to other large construction equipment pieces and construction safety products, increasing workplace safety and efficiency dramatically.