What Cause a Runway to Become Out of Span?

Aging crane runways can become out of span for many reasons but the most common reasons are building settlement, crane overloads, and crane malfunctions.

Building Settlement

Runway misalignment due to building settlement is common to most buildings containing bridge cranes and monorails. Buildings settle naturally anyway but with the added impact loadings that cranes produce they sometimes settle more quickly. This settlement results in runway elevations and spans becoming out of tolerance.

Crane Overloads

Crane overloads can lead to permanent deflection to bridge support columns and crane runways causing them to be out of tolerance. This out of tolerance condition will tend to worsen over time if left unchecked.

Crane Malfunctions

When a component of an overhead bridge crane fails, such as a wheel, wheel bearing, drive shaft or brake, it will often times cause the bridge crane to skew and become out-of-square. This can cause damage to the crane runway by spreading the runways apart and cause the runway steel to yield permanently, hardware to stretch and connection and rail bolts or clips to break. Many crane malfunctions such as broken drive shafts and worn bridge motor brakes can go undetected for a long period of time. These are the types of failures that can lead to catastrophic wear and damage to the structural integrity of the crane and runway.

Harriman offers a variety of solutions to combat these issues and a number of ways to detect these problems. Harriman inspection team will develop a course-of-action that will allow you to bring you structures, runways and overhead cranes back into compliance.