Author Archive for: Justin Bolduc


Overhead Crane Service Class Selection

Overhead Crane Service Class Selection easy as 1-2-3:

Selecting the correct service class for your overhead crane is usually quite simple.

1)Determine how you are going to use the crane.

  • a)How much weight will you be picking up.
  • b) How often you will be picking up the weight
  • c)How far will it be moved.

The class of crane service can significantly affect the design and the cost of the building framing used for the support of the crane system. The buyer should specify the crant service classification when requesting quotes from crane vendors or general contractors.

CMAA Crane Service Specifications:

  • 1) Service classes have been established to enable the buyer to specify the most economical carrier (trolley) or crane for the particular installation.
  • To determine proper service classification of equipment, it should be noted that there are three possible basic modes of operation to be considered. They are Crane travel, Carrier (Trolley) travel and Hoist travel. Specific requirements are shown for these components where design is influenced by classifications All classes of cranes are affected by the operating conditions; so for the purpose of these definitions, it is assumed that the crane will be operating in normal ambient temperatures (0°to 100°F) and normal atmospheric conditions (free from excessive dust, moisture and corrosive fumes)
  • 2) Class A
  • This class is further divided into two subclasses due to the nature of the loads to be handled.
  • 2.1 Class A-1 (Standby Service) – This service class covers cranes used in installations such as power houses, public utilities, turbine rooms, motor rooms and transformer stations, where precise handling of valuable machinery at slow speeds with long idle periods between lifts is required.
  • 2.2 Class A2(Infrequent use) – These cranes will be used in installations such as small maintenance shops, pump rooms, testing laboratories, and similar operations where the loads are relatively light , the speeds are slow and a low degree control accuracy is required. The loads may vary anywhere from no load to full capacity with a frequency of a few lifts per day or month.
  • 3. Class B (Light Service)
  • This service covers cranes such as those used in repair shops, light assembly operations, service buildings, light warehousing, etc.,where service requirements are light and the speed is slow. Loads may vary from no load to full-rated load with an average load of 50% of capacity with 2 to 5 lifts per hour and averaging 15 feet, with no more than 50% of the lifts at rated capacity.
  • 4. Class C (moderate service)
  • This service coveres cranes such as those used in machine shops, paper mill machine rooms, etc., where the service requirements are moderate.
  • In this type of service the crane will handle loads which average 50% of the rated capacity with 5 to 10 lifts per hour and averaging 15 feet, with no more than 50% of the lifts at rated capacity.
  • 5. Class D (heavy Duty)
  • This service covers cranes, usually cab operated, such as those used in heavy machine shops, foundries, fabricating plants, steel wharehouses,lumber mills, etc., and standard duty bucket and magnet operation where heavy duty production is required but no cycle of operation. Loads approaching 50% of the rated capacity will be handled constantly during the working period. High speeds are desirable for this type of service with 10-20 lifts per hour averaging 15 feet, with no more than 65% of the lifts at rated capacity.
  • 6. Class E&F (Severe Duty & Steel Mill Service)
  • Cranes in E&F class are covered by the current issue of The Association of Iron and Steel Engineers Standard No. 13for Electric Overhead Travelling Cranes for Steel Mill Service.


Overhead Crane Terminology

Overhead Crane Terminology

Overhead CranesMove in 3 Directions:

  1. Length, the length of a building or bay.
  2. Width, the width of a building or bay.
  3. Height, up or down.
  • The part of the crane moving the length is called the Bridge.
  • The part of the crane moving the width is called the trolley.
  • The part of the crane moving up and down is called the hoist.
  • These  three parts, bridge, trolley, and hoist together are called a crane
  • or overhead crane.

The following is a glossary of terms related to overhead cranes:

  • BAY: The space between the building frames measured parallel to the ridge of the building.
  • Brake: A device for retarding or, stopping motion by friction or by power means.
  • Bridge: a part of an overhead crane consisting of girders, trucks, and drive mechanism which carries the trolley and travels the length of the runway.
  • Building Aisle: A space defined by the length of a building and the space between building columns.
  • Capacity: the Maximum rated load (in tons) which a crane is designed to handle.
  • Collectors: Contacting devices for collecting current from the runway conductors. The mainline collectors are mounted on the bridge to transmit electrical current from the runway conductors.
  • Crane Aisle: That portion of the building aisle in which the crane operates, defined by the crane span and the uninterrupted length of the crane runway.
  • Crane girder: The principal horizontal beams of the crane bridge which supports the trolley and is supported by the end trucks.
  • Crane Span: the horizontal distance center to center of the runway beams.
  • Hand Geared: The operation of the bridge, hoist, or trolley of a crane by the manual use of chain and gear without electric power.
  • Hoist: a Machinery unit that is used for lifting and lowering a load.
  • Holding Brake: a brake that automatically prevents motion when the power is off.
  • Lift: The maximum safe vertical distance through which the hook can move.
  • Limit Switch: A device designed to cut off the power automatically at or near the limit of travel for the crane motion.
  • Pendant Push Button Station: Means suspended from the crane for operating the controllers from the floor or other level beneath the crane.
  • Rated load: The maximum load a crane is designed to handle.
  • Remote Operated Crane: a crane controlled by Radio Remote Controls.
  • Rotating Axle: An axle which rotates with a wheel.
  • Runway: The rails beams, brackets, and framework on which a crane operates.
  • Runway Conductors: the main conductors mounted on or parallel to the runway which supply electrical current to the crane.
  • Runway Rail: The rail supported by the runway beams on which the bridge travels.
  • Single girder Cranes: An electric overhead traveling crane having one main girder which supports a hoist mounted on a under running trolley.
  • Span: The horizontal distance center to center of runway rails.
  • (End)Stop: A device to limit the travel of a trolley or crane bridge. This device normally is attached to a fixed structure and does not normally have energy absorbing ability.
  • Support Column: A separate column which supports the runway beam of a top running crane.
  • Suspension system: The system (rigid or flexible) used to suspend the runway beams of under hung or monorail cranes from the rafter of the building frames.
  • Top Running Crane: An electric overhead traveling crane having the end trucks supported on rails attached to the top of the crane runway beams.
  • Under Running Crane: An electric overhead crane having the end trucks supported on track attached to the bottom flanges of beams or supported on the bottom flanges of the beams; these beams make up the crane runway.
  • Wheel Base: The distance from center to center of outermost wheels.
  • Wheel Load: The load without impact on any wheel with the trolley and lifted load (rated capacity) positioned on the bridge to give maximum loading.


Largest Floating Crane on Planet Earth

Do yourself a favor and click through to the full-sized images. They. Are. Insane.

Meet Kaisho, a floating crane owned by IHI in Japan with a lifting capacity of 4,100 tons. Kaisho is the largest floating crane on the planet. Dry Roasted Blend covered Kaisho’s smaller sister, Yoshida, back in 2007, but Kaisho is even bigger, towering more than 450 feet over the sea.

In fact, the 2 cranes worked together, along with a third massive floating crane, on the Tokyo Bay Highway Project in Japan. Pictured below, from left to right, is Musashi, Yoshido, and Kaisho.

Kaisho, Yoshida floating cranesSource: ykanazawa1999

The helicopter really puts the sheer size of these behemoths into perspective.

Massive Floating Cranes

3 Floating Cranes

The three cranes were used to hoist 760-foot bridge spans weighing 7,400 tons for the Tokyo Bay Highway Project . In an incredibly complex engineering ballet, these three monsters moved inch-by-inch from barges carrying the bridge spans to the installation point. During the move, GPS was used to coordinate both the position and height of each bridge span as it was carried into position. Because each crane’s hooks had different rolling speeds, Kaisho had to radio lift positions to each of the two smaller cranes over and over again so they could keep the massive spans balanced until they were in position.

Floating cranes with a bridge truss

If you take a look at the original size of the image above on Flickr you can see tiny little people on top of the concrete pillars.

Japanese cranes Kaisho and Yoshida

Largest Japanese crane Kaisho

Massive crane lift

Huge cranes with Ship

I managed to track down a photo taken from that same restaurant ship pictured above as it passed by the Yoshida:

Floating cranesSource: Symphony Cruise

This was the first time in 15 years that 3 floating cranes were used in a simultaneous lift in Japan.

After a bridge span was in place, one of the massive floating cranes lifted a 450 ton crawler crane 200 feet above sea level and deposited it into the girders to work on the upper truss. If you click the photo below to see the larger version you can really get an idea of the scale of these cranes. Notice the yellow crawler crane that looks like a toy compared to the massive floaters.

Floating crane lifts crawler crane into girdersSource: ykanazawa1999

A shot of Kaisho all alone.

Massive floating craneSource:

Kaisho largest craneSource:

Lifting a crawler crane into the bridge girders:

Biggest floating crane - KaishoSource

A photographer named Gunnar Horpestad has some images in his gallery of Kiasho working on the Dalia build at DSME.

And if you’re technically-inclined, you can read more about the lift here (pdf).

For more information on Crane-Tec, visit our product pages on single and double girder cranes, runway systems, jib cranes, and all types of hoisting systems.

Other Sources used:


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Engineering Library: 39 Fantastic Free Resources for Students

Free Online Engineering Education

  1. MIT OpenCourseWare
    MIT offers a huge variety of free online course materials on various topics, engineering being one of them. They have sections for Aeronautics and Astronautics, Biological Engineering, Chemical Engineering, Civil and Environmental Engineering, Electrical Engineering and Computer Science, Engineering Systems Division, Materials Science and Engineering, Mechanical Engineering, and Nuclear Science and Engineering.
  2. TUDelft OpenCourseWare
    Collection of free online courses from the Delft University of Technology. Subjects include water management, microelectronics, offshore engineering, nanoscience, media and knowledge engineering, and many others.
  3. Biological and Irrigation Engineering
    Free online courses from Utah State University.
  4. Civil and Environmental Engineering
    Free online courses from Utah State University.
  5. Electrical and Computer Engineering
    Free online courses from Utah State University.
  6. UC Berkley Webcasts
    Free online webcasts of various courses from UC Berkely. These are actual UC Berkeley Courses recorded and posted as webcasts online shortly after they’re recorded, so you can actually follow along with current course offerings. They also have archived courses going back to the Fall 2001 semester.
  7. Carnegie Mellon Open Learning Initiative
    Free online courses from Carnegie Mellon University.
  8. NPTEL Free Online Courses
    A collection of free online course materials in both video and text formats published as a joint venture between the Indian Institutes of Technology & the Indian Institute of Science. Includes basic, civil, computer, electrical, electronics & communication, mechanical, ocean, biotechnology, mining, and metallurgy engineering courses.
  9. LearnersTV Videos
    Collection of engineering videos and recorded lectures.
  10. Textbook Library calls these textbooks, but they’re more like educational introductions to topics like thermodynamics, reliability, distribution, permutation and combination, common materials properties, gears, bearings, and a number of other topics. You can also find some useful “cheatsheets” like a Table of Integrals, Table of Derivatives, Laplace Transforms, Common Material Properties, Constants, and units. Overall it’s definitely a good resource.
  11. All About Circuits
    An totally free and incredible collection of online textbooks on electricity and electronics by Tony R. Kaphaldt. Includes 6 volumes: (1) DC, (2) AC, (3) Semiconductors, (4) Digital, (5) References, (6) Experiments as well as a discussion forum.
  12. Engineering Reference Tables
    Another one from, this is a collection of reference tables on various topics like Color Codes for Resistors, Washer Size Charts, Normal Shock Waves, Conversion Table, Periodic Table, and quite a few more.
  13. Engineering Case Studies
    Published by the Rose-Hulman Institute of Technology, Carleton University, and the American Society for Engineering Education
  14. Free Video Lectures
    An aggregator pulling together video lectures from a number of different universities on quite a few subjects into one, conveniently browsable/searchable site.


  1. NSF Science and Engineering Statistics
    A great resource of original publications from the National Science Foundation.
  2. NST Virtual Library
    Huge library of resources from the National Institute of Standards and Technology. Includes everything from popular publications, to science handbooks, to science and engineering-related encyclopedias.
  3. Internet Math Library
    From the MathForum at Drexel University, the Internet Math Library is a huge collection of online math resources.
  4. Engineering Resources
    Directory of engineering resources
  5. Ethics Case Studies
    A collection of engineering ethics case studies published by
  6. Videos Related to Engineering
    All kinds of videos about all kinds of different topics engineers will enjoy.
  7. CFD Online
    An online center for Computational Fluid Dynamics. Features news, a wiki, a jobs database, events calendar, and discussion forums.
  8. NRC Electronic Reading Room
    Collection of online documents published by the U.S. Nuclear Regulatory Commission.
  9. IIE Knowledge Center
    An amazing collection of resources related to industrial engineering from the Institute of Industrial Engineers. Includes archives of thousands of whitepapers, magazine articles, conference proceedings, industrial engineering case studies, links to other online resources, archived issues of publications such as Industrial Engineer and Engineering Economist, and industrial engineering webinars. This is really an incredible resource that doesn’t even require registration.


  1. Newton Excel Bach
    Authored by Doug Jenkins, this is a blog geared toward people working with excel in scientific/engineering applications.
  2. Engineering &…
    A bi-weekly blog tracking current events in engineering.


  1. Pythonxy
    Based on the Python programming language, Pythonxy is a free scientific and engineering development software for numerical computations, data analysis and data visualization. Includes Qt Eclipse and Spyder.
  2. Scilab
    Another free platform for numerical computation with engineering applications.
  3. Octave
    A high-level programming language primarily intended for numerical computations. Mostly compatible with Matlab.
    ASCEND is a flexible modeling environment for solving hard engineering and science problems offering object-oriented model description language, an interactive user interface, and a scripting environment. Originally written by Carnegie Mellon University.

Discussion Forums

  1. Eng-Tips
    A relatively popular engineering forum with topical discussion focused on most engineering disciplines.
  2. Physics Forums Engineering Section
    A physics discussion forum with an active engineering section. Topics include General Engineering, Engineering Systems & Design, Mechanical Engineering, Electrical Engineering, Materials & Chemical Engineering, and Nuclear Engineering
  3. Engineer Boards
    Discussion forum with very active exam prep and exam discussion topics, among others.

Tuition Free Colleges

  1. The Cooper Union
    A tuition-free school located in Manhattan with programs in Engineering, Art, and Architecture. Founded in 1859 by Peter Cooper, who designed and built the first steam locomotive in the U.S.
  2. Franklin W. Olin College of Engineering
    Every admitted student receives a four-year, tuition scholarship valued at approximately $80,000.
  3. Webb Institute
    A tuition-free naval architecture and marine engineering college located in Glen Cove, NY, on Long Island Sound. Webb offers one degree option: a double major in Naval Architecture and Marine Engineering.
  4. Alice Lloyd College
    Most degrees focused on education, but they offer a number of programs in other areas, including a pre-professional program in engineering.
  5. U.S. Naval Academy
    Offers engineering-related majors in Aerospace Engineering, Computer Science, Electrical Engineering, General Engineering, Mechanical Engineering, Ocean Engineering, and Systems Engineering.
  6. U.S. Air Force Academy
    This one was incredibly difficult to find their list of degree programs. You can find a list of degrees around page 64 of this document. Engineering-related majors include Aeronautical Engineering, Astronautical Engineering, Civil Engineering, Computer Engineering, Electrical Engineering, Engineering Mechanics, Environmental Engineering, General Engineering, Mechanical Engineering, Systems Engineering, and Systems Engineering Management.
  7. U.S. Coast Guard Academy
    Offers majors in Civil Engineering, Electrical Engineering, Mechanical Engineering, and Naval Architecture & Marine Engineering.


Under-running crane and runway system case study

5 ton under running crane and runway system case study, with special considerations for tilt up concrete construction.

under running overhead crane system


To provide our customer, a leading trucking accessories supplier, with complete design build of an under running 5 ton crane system.  The job incorporated the 5 ton crane system and (2) ½ ton jib cranes.


The general contractor needed design build capabilities for the crane and runway system.  Crane-Tec provided complete design of the under hung runway system incorporated into the general contractors special crane truss system.


Our engineers, armed with building drawings, determined runway steel and hanger design.  Engineered drawings with loads were submitted to the general contractor for approval.  Crane-Tec’s experienced field crew installed the complete system and jib cranes in under 3 days to meet the G.C.’s demanding time parameters.


The general contractor maximized the strength of the building, Crane-Tec supplied a turn key crane system and the owner maximized floor space.  The cranes were ready ahead of schedule allowing the owner to set up manufacturing machinery with the use of the overhead crane.

Please feel free to contact us at anytime to discuss your project.  Our in-house project managers and engineers will be happy to assist you with all overhead lifting needs.

My family has been in the overhead crane business since my grandfather was a mechanic working on planes and overhead cranes in hangers during WWII.  We have always based our company around providing quality sercice, honesty and integrity.  It’s nice to remember my grandfater Bill, he was one heck of a crane salesman.  I was fortunate to have had a chance to work with him very briefly before he passed away some 13 years ago.  I’m actually sitting at his desk right now writing this blog entry, it’s an old desk scratched and worn from years of service, theres a lot of history here that I’m proud to be a part of.

Please feel free to contact me directly @ 513-851-1655.

Have a good day,

Justin Bolduc



Overhead Crane Case Study 15 Ton Double Girder Cranes

15 Ton Double Girder Overhead Crane Case Study

15 ton top running double girder overhead crane

The Challenge:

To provide our customer, a major automotive parts manufacturer, with a freestanding runway system for a new facility in Ohio. The job incorporated (7) seven 15 ton double girder overhead cranes complete with freestanding runway systems.

Special Consideration:

The general contractor needed design build capabilities for the foundations and runway systems. Double girder overhead cranes with low headroom hoists were utilized to minimize crane and building steel costs.  Crane-Tec engineers armed with metal building drawings designed a cost efficient and space saving runway system.  All cranes were installed with hoist monitoring systems which facilitate scheduled maintenance and allow for problems to be detected before turning into costly breakdowns.


The general contractor maximized the strength of the building by utilizing tie-back columns along exterior walls; Crane-Tec supplied a complete crane system and the owner maximized floor space.  The overhead cranes were weight tested and turned over to the customer ahead of schedule.

 For Immediate Results

Call 800-755-6378



Crane-Tec Overhead Crane Case Study 1

10 Ton Freestanding Overhead Crane Case Study

Picture of overhead Crane

The Challenge:

To provide our customer, a carpenters training facility, with a freestanding runway system for a new facility in Indiana. The job incorporated (1) Ten ton top running single girder  overhead crane and complete freestanding runway systems.

Special Consideration:

The general contractor needed design build capabilities for runway systems. Single girder overhead cranes with low headroom hoists were utilized to minimize crane and foundation costs.  Crane-Tec engineers armed with building and foundation drawings designed a cost efficient and space saving runway system.


The general contractor maximized the space inside of the building.  Crane-Tec supplied a complete overhead crane system and the owner maximized floor space.  The cranes were completed and turned over to the customer ahead of schedule.