Replacing Arch Beams: Your Plant’s Safety Depends On It!

What IS Arch Beam? Arch beam is a type of crane that looks like the ones in Figures 1 and 2 below. Though it hasn’t been manufactured since 1962, it is still in use in plants throughout North America. Companies need to be aware of the possible dangers posed by age and fatigue in the welds of Arch Beams in customer’s facilities. Figures 1 & 2

Why is Arch Beam a Concern? “Converging Climatic forces at work” 100% of the Arch Beam crane fleet in service is more than 45 years old Many systems have seen dramatic increases in cycles. Inspection and maintenance procedures have been outsourced to inexperienced vendors. Lower operator awareness of wearing mechanisms.

Hidden Danger Most users today are unaware of hidden failures and potential danger: Cracks in welds and lower T Sections Tracks with raised tread worn away Most cranes have exceeded their useful life expectancy, but some users see cranes as “timeless”. Current inadequate crane maintenance regulations may lull owners into a false sense of security about crane safety and/or conditions.

Changing Times, Changing Technology Technology is changing the way cranes are: Designed – Current Tarca® Beam design incorporates a full web plate, higher strength to weight ratios, and uniform plate dimensions Manufactured – Automated continuous welding processes have replaced the original “stitch” welding used to fabricate Arch Beam

Technology is changing the way cranes are: Operated – The majority of Arch Beam Systems were designed for manual propulsion. They were later upgraded to motorized systems Maintained – During the 1940’s and 1950’s, most companies employed their own crane maintenance departments. Inspections and repairs were performed on a regular basis. In today’s culture of outsourcing, crane inspections are contracted to the lowest bidder, who may not be familiar with patented track systems

Why Was Arch Beam Discontinued? Wide flange beam tolerances were too variable, leading to: - Beams out of square - Variations in depth - Distortions in the web - Loss of capacity due to secondary deflections in the arches Lateral deflection, which under certain conditions can impose a great amount of reaction into the unsupported portion of the lower flange, thereby, increasing the possibility of weld failure

Why Was Arch Beam Discontinued? Concentration of stresses at the start of the arch caused cracks to appear in the lower high carbon rail. This was especially true if the welder nicked the top portion of the rail section with the welding rod at the start of the weld Martensitic Failure of the welds has resulted in the bottom rail peeling away from Arch Beam web in a “zipper” effect.

Arch Beam Welds Hand Welds are stitched intermittently along the bottom Tee section Nicks at the start of each weld can weaken the connection over time. Cracks can form in the Tee section at start of each weld

Arch Beam Concerns Due to the age of equipment, the exact understanding of a crane’s design duty cycle may be difficult to determine without engineering analysis. (i.e. documentation may be missing) This increases the possibility for usage outside of its original intent. In some cases up-rating equipment by less qualified personnel can also lead to these failures.

Arch Beam Concerns Since many existing parts are using outdated engineering, replacement parts must be reviewed for application before installation. Wheel sizes have changed Equivalent Center Load Ratings have changed to reflect the current Tarca™ design. Historical failures have pointed out that in addition to standard maintenance practices, the lack of recording significant events led to over- estimating crane life expectancy.

Warning Signs to Look For Keep an eye out for these warning signs of components at risk of failure: Cracked Welds Cracked lower rail sections Oxidation of materials (Rust) Flat treads Worn castings

Got Arch Beam? Here’s what we recommend Our primary recommendation is to Replace All Arch Beams with Tarca ™ Beams If this is economically unfeasible, conduct regular safety audits Safety Audits: Steps to a safer and more reliable crane Use only skilled personnel for the audit Identify the highest risk cranes in your inventory by age and cycles. Study and compare the original design versus the current usage

Got Arch Beam? Here’s what we recommend Fully inspect every weld in the beam. Through inspections, find discontinuity and then use non destructive testing. Benchmark critical components using reliability based maintenance practices and software. Inspect spare parts inventory to ensure what may be required in repair will be available in advance. This reduces the chance of downtime. –Please Note - Gorbel does not stock nor manufacture components for Arch Beam Systems.