Case Study: Unique Free-Standing Crane System

Overhead crane system and workstation crane designed to spec for leading fabrication and engineering firm

Introduction

Throughout its 35-plus years in business, Crane-Tec has been equipping a wide range of industries with a wide variety of overhead crane systems, including runway systems, monorail hoists, and jib cranes. Crane-Tec has been a leader in furnishing, installing and servicing such systems. Its diverse customer base includes general industry, power plants, the aviation industry, concrete products manufacturers, the automotive industry, machine shops, place injection mold facilities, metal service centers, tool and die facilities, general fabrication facilities and waste water treatment facilities. In addition to designing overhead crane systems, Crane-Tec also does the fabrication and installation.

Often times, Crane-Tec is presented the opportunity to design a freestanding overhead crane system. Although overhead cranes are custom designed to an extent (since the span and capacity are determined by the customer’s needs), a freestanding runway system is completely custom-designed. These customizations are sometimes the result of a building not designed for overhead cranes, which was the situation Crane-Tec faced when a leading fabrication and engineering firm in Indiana needed multiple overhead cranes and runway systems in a building that was designed for a different use.

Challenges

Custom design of an overhead crane system for this customer presented some unique challenges for Crane-Tec and its engineers. When Crane-Tec surveyed the building purchased by the end user, it was confirmed that the building was not designed with overhead cranes in mind. In this situation, Crane-Tec needed to design free-standing runway systems that were completely independent from the building structure.

Another challenge was meeting the scope of work performed by the end user. As an integral part of the fabrication process, the user needed cranes to move components throughout fabrication, assembly, and loading the finished machines onto trucks. The cranes also needed to move machines in various stages of assembly from workstation to workstation within the building. In addition, the customer needed a crane system that would allow constant reconfiguration of work areas depending on what was being fabricated.

These requirements led to a unique and complex runway system that featured:

  • A very large span for the cranes to keep the building’s floor clear of columns that would interfere with workflow.
  • Jib cranes supported from the runway columns, which differs from typical jib crane installations where the jibs are usually hung from the building or stand independently.
  • A multiple crane system to accommodate a workflow where heavy components are constantly moving.

After multiple site visits, Crane-Tec determined that a 20-ton freestanding runway system was needed, which presented its own unique challenges. First, 20 tons is a rather high capacity for a freestanding runway system being designed to fit inside an existing building. Secondly, adding jib cranes to runway columns requires special columns and footers specially engineered for this project.

The Solution

After addressing the needs and challenges of the steel fabrication and engineering company, Crane-Tec arrived at the solution of a 20-ton freestanding runway system; two  10 ton, 70-plus foot span single box girder cranes; multiple 2 ton jib cranes; and a 2 ton freestanding workstation crane. The solution was a result of Crane-Tec working with the customer to assess their needs, price out multiple options and determine the most cost-effective avenue for the customer.

It’s common for customers to compare the cost of a number of different configurations since crane availability and the location of the runway columns will impact workflow. Many other factors come into play when deciding on the best overhead crane system for the application. In this case, however, functionality, workflow and cost were the three main driving factors.

The Design Process

Once a solution was identified, Crane-Tec worked with the customer and the general contractor to design the customized overhead crane system. Since the freestanding runway system was being installed in an existing building, a site visit was needed to take accurate measurements and assess the structure’s layout.

Runway layout is the most important aspect of an overhead crane system. Generally, the customer knows the required capacity of the crane. Crane-Tec then discusses with the customer how frequently the crane will be used and the size of the loads it will be picking up to determine the classification of the crane. With this detailed information, Crane-Tec engineers design, fabricate, and install the crane system.

Installation

Installing such a complex freestanding crane system is no easy task, which is where Crane-Tec’s 35+ years of experience pays off. For the 20-ton freestanding runway system, the general contractor modifying the building had to install concrete footings. The Crane-Tec installation crew was also on site with the necessary installation equipment, including man lifts and a carrydeck crane. The Crane-Tec crew installed anchor bolts for the columns in the footing and then the columns were installed and shimmed to level. Next, the runway beams and crane rail are bolted to the columns and adjusted to meet exacting tolerances. The entire installation process took about 2-1/2 days.

The 2-ton freestanding workstation crane was installed in the same manner as the freestanding runway system. The installation time was about two days.

For the two, 10-ton, 70-plus foot span single box girder overhead cranes, the Crane-Tec crew installed the hoist and festooning on the crane girder, which is the main horizontal beam of the crane bridge that supports the trolley and is itself supported by endtrucks. Once in place, the crane girder, including endtrucks (or the wheels that support the bridge girder), was set on the runway. Assembling and setting the 10-ton cranes took about one day.

The multiple 2-ton jib cranes were cantilever style, consisting of a steel beam with a hinge on one end. The hinge was bolted to the runway column. Then a hoist was installed on the jib crane beam. Each jib took one to two hours to install.

Once all the cranes and supporting equipment were installed, the Crane-Tec crew spent a day starting up and testing all the cranes. Crane-Tec provides an overview on how to operate the equipment and safe operating procedures upon request. This is in addition to an operational and maintenance manual provided with each crane.

Results

The Crane-Tec freestanding crane system is already making a big difference in workflow and production levels for the steel fabrication and engineering firm. The two overhead cranes allow the company to move and position materials before and during fabrication, thus improving time efficiency. The overhead cranes are also utilized for unloading raw materials from trucks, loading fabricated goods on trucks, and moving steel/machines during fabrication from one work area to another.

Without the freestanding crane system, none of this production work could have been performed in the building. The only other option was for the steel fabricator and engineering firm to free up considerable space in the building so materials could be moved by mobile cranes and large fork trucks, a consideration that was not feasible from a cost or work efficiency standpoint.

The Crane-Tec crane system is providing time-saving processes and an easier workflow. The company has already justified the expense of installing the freestanding runway system, single box girder overhead cranes, jib cranes, and freestanding workstation cranes, and is well on its way to realizing its return on investment.

 

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