Crane Failures & Lessons Learned
Cranes are essential in industries ranging from construction to manufacturing, but when things go wrong, the consequences can be severe. By analyzing real-world crane failures, we can gain critical insights into safety protocols and best practices that help prevent future accidents.
Case Study 1: The Big Blue Crane Collapse (1999)
In 1999, the Big Blue crane collapsed at the Miller Park construction site in Milwaukee, Wisconsin, causing the deaths of three workers. The collapse was attributed to the crane, a heavy lift crawler crane, operating beyond its design specifications, with an unsafe combination of load and wind conditions. A 450-ton stadium roof piece was being lifted amid an average wind speed of 26 mph, with gusts that were estimated to reach the mid-30s. While the crane was operating at 97% of its rated capacity, the extreme weather conditions were not considered in the lift plan, causing the load to exceed its safe limit.
Lessons Learned:
This tragic incident highlights the importance of thorough weather assessments before crane lifts. In the case of Big Blue, while wind effects on the crane were considered – and even at that, were pushing the boom’s wind rating of 20 mph – the wind’s impact on the load was overlooked, emphasizing the need for proper load calculations that account for both crane and load stability. Stricter wind-speed restrictions, aligned with manufacturer guidelines, are essential to minimize risks in such conditions. Additionally, crane operators should always have the final say in lift safety. In this case, the crane operator raised concerns about lifting in high winds but was overridden.
Case Study 2: The New York City Tower Crane Collapse (2008)
In Manhattan, a tower crane collapsed due to overloaded polyester slings that were not properly protected from sharp edges. The slings, which were suspending a steel collar, were rated for 12 tons each, but were lifting a 23-ton load. As well, only four slings were used instead of the required eight. The rigging company also neglected to inspect the nylon slings, unaware that one was damaged. As the workers were tightening the bolts to secure the collar, the damaged sling snapped, kicking off the domino effect that led to the crane collapsing. The collapse resulted in seven fatalities. Other contributing factors included insufficient worker training, poor communication among contractors, and a lack of oversight by the city’s Department of Buildings, which had issued multiple safety citations prior to the disaster.
Lessons Learned:
The collapse pointed to the necessity of strictly adhering to manufacturer guidelines, particularly when it comes to rigging procedures. Using equipment beyond its rated capacity, such as overloaded slings, can result in devastating failures. It’s also essential to protect equipment from damage, such as ensuring slings are not exposed to sharp edges, which can cause abrasion and weakening. Effective communication and coordination among all parties, including contractors and operators, are vital to prevent misunderstandings and ensure alignment on safety protocols. Finally, strong oversight and enforcement of safety regulations are necessary to avoid preventable accidents.
Case Study 3: The Alphen aan den Rijn Twin Crane Failure (2015)
Two mobile construction cranes, each placed on a barge, collapsed while attempting to lift and place a bridge section in the Netherlands. Both cranes and the bridge section fell into a nearby area, destroying several homes and shops. Fortunately, there were no injuries despite the significant damage. The incident was attributed to improper weight distribution and inadequate planning for ground stability, causing the cranes to tip over onto the nearby buildings.
Lessons Learned:
The Alphen aan den Rijn twin crane failure emphasizes the need for thorough planning and risk management, particularly when cranes are used on unstable platforms like barges. The Dutch Safety Board (DSB) found that even flawless execution would have led to failure in this event. The cranes and barges were used beyond their rated capacities, and the absence of contingency planning for barge stability exacerbated the situation. Stability calculations must consider crane flexibility, ballast distribution, and external forces. The absence of a ballasting plan prevented timely correction of any inclination, compounding the instability of the setup. Additionally, the lack of a safety margin to absorb unexpected forces, such as crane movement, contributed significantly to the collapse. This accident stresses the significance of involving engineers in the planning phase and ensuring real-time monitoring and oversight during complex lifts.
Case Study 4: Taichung Crane Collapse (2023)
The Taichung crane collapse occurred in May 2023 when a crane boom, being dismantled on the 31st floor of a building under construction near Feng-le Park Station on Taichung’s Green Line, fell onto the tracks. A driverless MRT train left the station and collided with the debris. The impact caused the train to eventually come to a stop, but tragically, the crash resulted in the death of one passenger and injuries to others.
The investigation revealed that the crane operator and signalman noticed a jammed temporary pin and rotating plate on the crane but failed to follow the proper dismantling procedures. This oversight led to the crane’s collapse. The failure to adhere to safety protocols during the dismantling process ultimately caused the crane boom to fall, leading to the collision with the train. These findings are based on current reports, ongoing investigations might reveal additional factors beyond procedural lapses.
Lessons Learned:
The Taichung crane collapse underscores the need for strict adherence to safety protocols, especially when operating cranes near public areas such as transit systems. Even when issues are identified, such as the jammed pin, operators must follow proper procedures and never proceed until the issue is resolved. In urban environments, where public safety is a concern, thorough risk assessments should be conducted before any crane operation, and all parties involved must be diligent in following safety guidelines. Regular reviews and enforcement of operational guidelines are necessary to prevent human error and lapses in judgment from resulting in catastrophic accidents.
Building a Safer Future
These case studies highlight different aspects of crane operation safety, each offering valuable lessons that contribute to improving overall safety standards in the industry. Whether it’s understanding weather impacts, following proper rigging procedures, ensuring stability in complex operations, or adhering to safety protocols in high-risk environments, these incidents emphasize the need for thorough planning, rigorous risk assessments, and consistent adherence to safety guidelines to prevent future accidents.