A typical tower crane has a maximum lifting power of almost 20 tons. That kind of capacity can be a considerable boon in construction but also means multiple tons of weight can be wearing down various parts of the crane when it’s in use.
Tower cranes are mighty machines, but if something goes wrong, it can be disastrous. Learn how long to expect one to last and what to watch out for here.
1. See the Signs in Tower Crane Deterioration
Tower cranes, among other crane breeds, are especially powerful, so safe operation should be a priority.
There are two critical features linked to crane deterioration: structural fatigue and corrosion.
While the latter can be more detectable, structural fatigue requires assessment through testing. This is just one of the reasons why testing is essential.
In short, structural fatigue is simply the growth of a crack in the crane. This is more common in welded connections due to inconsistencies in the metal used for welding.
Here is a helpful process for diagnosing how long a crane is safely functional:
- Assess the number of cracks and crack potential to determine current crane condition
- Estimate crane life before testing
- Conduct regular testing process as scheduled
- Estimate crane life after testing
The crane life estimations in this process aren’t just operator predictions, which are prone to human error.
Instead, these estimations are generated computer models of the crane’s overall condition, which incorporate structural drawings as well as the crack assessments.
If anything, this process outlines how necessary testing is. In this case, testing is used as a landmark within a crane’s life.
2. What to Expect in Tower Crane Life Expectancy
While some cranes can last decades, some don’t, and it can be challenging to determine the future quality of performance for the ones that do last.
To estimate a crane’s condition, you can assess the crane’s “load cycles.”
For these load cycles, you can record three parts of data from the crane lifting process:
- The boom strains: the amount of wear that the crane’s lifting arm takes.
- The loading line forces: the amount of force that the main hoisting cable faces.
- The number of “picks”: the number of lifts that crane performs.
- The tower strains: the amount of wear that the tower faces.
While there isn’t a way to determine exactly how much service life a crane has, counting cycles determines how much action the crane has experienced.
In a study conducted by Haag Engineering Company, the average age of a crane was estimated to be around 16.9 years old.
Although crane life expectancy varies depending on various factors, cranes have also been expected to live to 25 years or more.
Evidence of remaining service life for a crane relies upon the amount of accumulated damage. Without assessing machinery wear, there is no way to determine how a crane can be further used.
Compared to crack assessment, counting the loading cycles may be less exact. This is because the results from crack assessment are based on specific measurements of inflicted damage and not just use.
3. Tower Crane Testing Reveals Hidden Machinery Risks
Testing altogether avoids the issue of making false assumptions about a tower crane’s life.
In the past, older cranes were often more dangerous than expected or immediately apparent. The fact was that older tower cranes didn’t (and don’t) always show clear signs of fatigue.
Most crane owners now install only newer components, because older ones pose safety risks.
However, without operational testing and inspections, cranes can appear to operate normally but remain structurally unsound.
This is why various parts of the crane, especially the old climbing cages, are required to appear in “like-new” condition.
The Best Way to Understand Tower Crane Life
Although there are many variables in crane life, awareness is the best course of action for safe operation. It may seem intuitive, but staying aware of the condition for each crane informs how much service it can give you.
In addition to this, you can find out how to improve tower crane life through crane modernization and upgrades.