A production building was being constructed at a cement plant. A large crawler crane was being used to install the pre-assembled metal wall framing of the building. The weights and lift radii of the four wall framing sections, along with the rigging spreader and other lift equipment, were within the rated capacity of the crane.
The use of taglines attached to the wall framing sections and controlled by personnel on the ground was essential to control the wall framing section positions and to prevent unwanted rotation during the crane lifts. The lifts were being conducted in an exposed lakefront area that was known for wind gusts that could affect the crane load.
The first three wall sections were installed without incident. The fourth wall section had to be lifted high enough to clear two other sections that had already been installed. The taglines being used were not long enough for the extra height of this lift, so the ground personnel released the taglines with the intent of taking control of them as the wall section was lowered.
The fourth wall section rotated during the lift and could not be lowered enough for the taglines to be reached without hitting production equipment that was already in the building.
Rather than aborting the lift and returning the wall section to the original lift point, the crane operator was directed to lower the boom and increase the lift radius until the taglines could be reached. This action overloaded the crane boom and caused it to collapse, damaging the boom, as well as structures on the ground that were struck by the falling boom.
The causes of the incident were the use of taglines that were too short to maintain constant control of the load, followed by the decision to release the taglines, and then lastly, to increase the load radius to recapture the taglines. These were all errors by the lift director, who was responsible for the incident.
The Code of Federal Regulations and ASME Crane Standards provide regulations and industry standards concerning the use of taglines and the role of the lift director.
John Phillips, senior consulting engineer at Warren, has more than 30 years of crane and heavy equipment experience and more than 17 years of experience in forensic engineering. A licensed professional engineer in South Carolina, North Carolina, Georgia, Louisiana and Ohio, he’s NCEES registered both as a model engineer and with The United States Council for International Engineering Practice, USCIEP. John has designed crane systems, supervised installation, tested and certified lifting equipment even serving as a project engineer for maintenance and certification of nuclear weapon lifting and handling systems. John is a certified fire and explosion investigator and fire and explosion investigator instructor by the National Association of Fire Investigators. John is a member of the American Society of Materials and American Society of Testing and Materials, as well as a voting member of ASTM Ships & Marine Forensic Sciences, Forensic Engineering, and Performance of Buildings committees.