What Causes a Mobile Crane to Topple: Solutions for Safe Crane Operation

If you’ve ever marveled at a tall mobile crane as it lifted and moved massive amounts of weight during a construction job, you may have wondered what was keeping the crane from simply tipping over. How does a crane carry such massive loads while still remaining balanced?

The reality is that there is always some risk that a mobile crane could topple. That’s why a great deal of engineering has gone into ensuring that the equipment is sturdy and secure and operators are trained and certified. When it comes down to it, ultimately, the safety of any jobsite depends on the crane operators themselves.

At West Coast Training, we spend a great deal of time training our students on safe crane operations to mitigate the risk of toppling cranes and other major construction incidents. In this article, we’ll share some of what we cover in our classes, helping to ensure crane safety on any jobsite.

How Do Cranes Stay Up in the First Place?

In physics, the difference between an object staying upright and falling over is a matter of torque. Torque is the force that causes rotation, which occurs around the fulcrum, or pivot point, of an object. The greater the distance from the center of mass of an object to the fulcrum, the more torque will be generated, and the more easily an object can be rotated.

This is why top-heavy objects, like an overladen crane, can sometimes tip over. The excess torque generated by the weight on the top of the crane can simply pull the crane over unless steps are taken to prevent this.

Well-designed mobile cranes have several features that prevent them from becoming too top-heavy. First, the design takes into consideration the amount of torque that will be generated by a given load. The boom on the crane is designed at a certain length with that concept in mind. The width of the crane’s carrier also has an impact: objects that are wider at the bottom are less likely to tip over.

Cranes are also equipped with counterweights, which are strategically placed opposite the fulcrum point of the boom itself. These are heavy metal weights that apply an opposing force to the weight on the crane arm, helping to prevent toppling.

How Cranes Can Topple

While cranes are engineered in such a way as to prevent toppling, unsafe practices in their operations can still affect their center of mass in such a way as to create more torque than the cranes are built to handle. This, in turn, causes them to fall over.

Several factors can contribute to a mobile crane toppling over. Inclement weather—especially heavy winds—can be a factor, although this is actually not responsible for most toppling incidents. Nevertheless, operators should always be aware of weather conditions before beginning any task involving heavy equipment.

The soil that the crane sits on also can contribute to its risk of tipping. If the ground beneath a mobile crane is too soft—perhaps as a result of recent rains or a marshy environment—it can cause the crane to sink partially into the earth. If this occurs, the crane may no longer sit flat on the ground, which can cause it to fall. Operators should avoid driving mobile cranes into areas where the soil is too soft.

Human error with regard to the use of the equipment itself is probably the biggest cause of crane toppling incidents. Cranes are designed to handle only a certain amount of weight. Adding too much of a load can overwhelm the counterweights and lead to a toppling incident. Improper use of the controls can also cause cranes to fall over. For example, attempting to lift a load too high, beyond what is recommended by the manufacturer of the crane, can cause a crane to fall.

Know the Load Limits

At West Coast Training, we spend a great deal of time teaching our students how to assess a jobsite for safety. If the conditions aren’t right to perform a job, the operator should make a judgment call that the crane cannot be used safely. If safety would be compromised, then the job should be postponed until a later time.

Of course, workers aren’t expected to memorize the ins and outs of every single crane that they will be using. Instead, they are taught to familiarize themselves with load charts, which tell them the load limits for each crane and how high that load can be lifted. Each crane will have one that the operator should read before getting behind the controls.

Keep the Equipment in Good Condition

Sometimes, when a crane tips over, it’s a result of equipment failure. Ultimately, however, this still boils down to human error. It’s the responsibility of the construction company and the crane operators to ensure that their equipment is in good working order every day.

Part of what crane operators learn in West Coast Training’s crane operator programs is basic maintenance. They should be able to assess all parts—treads, pulleys, cables, bolts, and everything else—to ensure that a crane is safe to use on a jobsite. They can also perform basic on-site maintenance as necessary.

The Importance of Training

Since the vast majority of crane toppling incidents are in some way the result of operator error, most employers will insist on having highly trained, experienced workers behind the controls of their cranes. At West Coast Training, we offer both classroom learning and on-the-job experience, which culminates in students earning their NCCCO certification, a credential critical for being hired for most jobs. Of course, crane safety practices are a constant focus of our program.

With enough experience, crane operators learn to become more and more intuitive about safety conditions on a jobsite. They can quickly assess whether or not a mobile crane can be safely put to use for a given task in a given area. This attention to detail is what helps to prevent crane toppling incidents from occurring in the first place.