Basic Crane History

  • A crane, also known as a bridge crane or overhead crane, is a type of machine used for lifting. Cranes are generally equipped with a winder (also called a wire rope drum), wire ropes or chains and sheaves, that can be used both to lift and lower materials and to move them horizontally. It uses one or more simple machines like a hoist to create mechanical advantage and thus move loads beyond the normal capability of a human. Cranes are commonly employed in the transport industry for the loading and unloading of freight, in the construction industry for the movement of materials and in the manufacturing industry for the assembling of heavy equipment.
  • The first construction cranes were invented by the Ancient Greeks and were powered by men or beasts of burden, such as donkeys. These cranes were used for the construction of tall buildings. Larger cranes were later developed, employing the use of human tread wheels, permitting the lifting of heavier weights. In the High Middle Ages, harbor cranes were introduced to load and unload ships and assist with their construction – some were built into stone towers for extra strength and stability. The earliest cranes were constructed from wood, but cast iron and steel took over with the coming of the Industrial Revolution.
  • For many centuries, power was supplied by the physical exertion of men or animals, although hoists in watermills and windmills could be driven by the harnessed natural power. The first ‘mechanical’ power was provided by steam engines, the earliest steam crane being introduced in the 18th or 19th century, with many remaining in use well into the late 20th century. Modern cranes usually use internal combustion engines or electric motors and hydraulic systems to provide a much greater lifting capability than was previously possible, although manual cranes are still utilized where the provision of power would be uneconomic.
  • Cranes exist in an enormous variety of forms – each tailored to a specific use. Sizes range from the smallest jib cranes, used inside workshops, to the tallest tower cranes, used for constructing high buildings. For a while, mini – cranes are also used for constructing high buildings, in order to facilitate constructions by reaching tight spaces. Finally, we can find larger floating cranes, generally used to build oil rigs and salvage sunken ships.


Overhead Cranes in New Buildings

Industrial buildings, as well as some other building types, require large clear spans and heavy loadings. It is generally conceded that a tapered web-rigid frame is one of the most economical types of framing for the loads and spans normally encountered in crane buildings. When conditions beyond the normal are encountered, a truss frame may be more appropriate.

The building manufacturer should be given the opportunity of recommending the building type and support system to be used for the cranes.

Top-running Cranes

Runway beams for top-running cranes located within the building may be supported by brackets attached to the building frame columns, by separate columns located inside and in line with the building frame columns, or by stepped. When crane aisles extend outside the building, A-frames are commonly used to support the runway beams.

Brackets on the building columns are commonly used to support the runway beams for cranes up to 10-ton capacity. However, cranes with up to 20-ton capacity may be supported in this manner depending on the type, span, and service classification of the crane.

For cranes of more than 20-ton capacity, it may be more economical to support the runway beams with separate support columns. However, the columns for buildings having high eave heights and/or large wind and snow loads may support heavier cranes without substantial weight penalty.

Runway beams for cranes with capacity of 20 tons or less, but with bridge spans greater than 50 feet, may also be more economically supported by separate columns.

Underhung Bridge Cranes

Runway beams are supported by hangers or brackets attached to the rafter of the building frame. The location of the support hanger can materially affect the design, shape and economy of the building frame.

It is usually more economical to purchase a crane with a bridge span approaching the building width. This places the crane end trucks near the building columns. The savings in the building support framing will normally exceed the extra bridge cost. This savings can be substantial in long buildings with a large number of frames.

Underhung Monorail Cranes

Runway beams for underhung monorail cranes are supported similar to runway beams for an underhung bridge crane.

Crane loads and other crane data varies between crane manufacturers. These variations can affect the design and economy of a crane building. Significant economics may be achieved if the crane manufacturer is selected prior to the design of the building. This provides the building manufacturer with specific crane data for design of the crane building. For crane loading information, please consult us.


Preventative Maintenence

Why does Crane-Tec recommend performing a preventive maintenance service on a quarterly basis?

  • Many crane owners have inspections performed on an annual basis. This is an OSHA requirement. What many companies don’t know is OSHA also requires that the crane must be maintained on a scheduled basis, complete with dated records based upon the manufactures criteria. The maintenance can be performed in house or by a third party and the schedule is based on the duty cycle of the equipment along with following the manufacturer’s requirements.
  • Aside from the mandatory requirements listed and their costs, there may be additional costs involved by doing only an annual inspection. Historically, cranes with only an annual inspection/preventive maintenance service incur more break downs than cranes serviced quarterly. Small problems or adjustments normally taken care of during a quarterly inspection/preventive maintenance service have become bigger problems by the time the annual inspection/preventive maintenance service is due. Deficiencies found on an annual inspection/preventive maintenance service may be multiplied vs. cranes being inspected and maintained quarterly.
  • When breakdowns do occur, production time is lost and repair costs rise. If one was to look at two identical cranes of the same age, running at the same duty cycle and one unit maintained quarterly, the other maintained annually; you would find that the equipment maintained annually would cost more in higher operating costs, with lost time and expensive repair bills.

Benefits of Performing a Quarterly Inspection/Preventive Maintenance Service

  • 1) Lower your costs on repairs, including expediting costs and airfreight bills when purchasing replacement parts.
  • 2) Decrease your equipment down time due to breakdowns.
  • 3) Allows you, the Crane Owner and Crane Service Company to schedule repairs around your production.
  • 4) Provides you and your staff advanced notice of equipment condition for future and existing budget requirements.
  • 5) The above cost savings alone can be enough to allow for future upgrades or equipment replacement.

Are you proactive or reactive when it comes to maintaining your overhead cranes and hoists? Why take a chance, let a qualified Crane –Tec specialist recommend the correct program for your operation.


What Is an Overhead Bridge Crane?

According to the United States Department of Labor’s Occupational Safety and Health Administration, “Overhead crane” means a crane with a movable bridge carrying a movable or fixed hoisting mechanism and traveling on an overhead fixed runway structure. These devices are widely used in many industrial environments where large and heavy items require moving from one location to another.


Overhead bridge cranes have long been used in factories and warehouses to hoist and move heavy objects, often in small or cramped areas that may not allow for proper and safe maneuvering of forklift trucks. An overhead bridge crane can remedy this situation by providing an effective manner to hoist and move heavy loads that require significant power capability. It can readily meet numerous requirements that are sometimes performed by other types of equipment.


Overhead bridge cranes can be divided into two groups: top-running bridge cranes and under-running bridge cranes. The primary distinction is the manner in which the end trucks are attached to the crane. Top-running overhead bridge cranes have the end trucks supported on rails attached to the top of the crane runway, while under-running bridge cranes have the end trucks supported on tracks attached to the bottom flanges of the beams.


The benefits of an overheard bridge crane, whether top-running or under-running, are fairly numerous and can be significant solutions to alternative methods such as forklifts and elevators. A major benefit is that overhead bridge cranes are considerably less expensive than other options. They are also of a relatively simple design, lending to ease of operation and can be ordered as kits and installed on-site by the purchaser. They are designed so that in case of failure, they lock their load in place and prevent it from falling.

Shortcomings of Overhead Bridge Cranes

The primary–and possibly only–drawback to having an overhead bridge crane is that they are not very mobile. However, even this situation can be remedied by installing a track network to extend the range of the crane. This added expense still allows an overhead bridge crane to be a more economical choice than a forklift. The fact that an overhead bridge crane can actually reduce or even eliminate the need for forklifts or freight elevators is also a considerable benefit.


When pondering the need to acquire equipment that allows for the safe and efficient relocating of heavy objects as is required in warehouse environments and the like, an overhead bridge crane is a candidate for serious consideration. They are readily available to be shipped in kit form, can be configured to meet just about any application requirements and are safe when properly installed and operated. They are very suitable for small spaces and require less electricity to operate.

For any help in deciding your crane needs please contact us at Crane-Tec 800-755-6378 or


Overhead Crane Classification

Determine the proper CMAA classification for your crane:

Having been in the crane industry for more than 30 years, I have noticed that a reoccurring  problem I encounter on a daily basis is the determination of the CMAA classification of a particular crane. The problem lies in the broad wording used in the classification charts as well as an end user, builder and even some crane sales persons I have encountered just making a determination without even looking at the specification charts and true application.
The proper determination is crucial to the correct crane being specified for each application. In the current state of our industry, this is becoming even more critical as crane manufactures are engineering all their components to much tighter specifications in order to be cost competitive. Today,components are no longer being over built and almost everything is built to the specification required. Thus the proper classification is extremely important in today’s crane world.
I came across this simple way to determine the specification necessary years ago and still implementing this strategy today. While in some of the higher specifications further examination may be necessary but this will get you pretty close in almost any situation. It is based on a points system and pretty self explanatory. You go through each area and make the proper number selection and then add them all up and use the matrix to determine your classification. The key here is to be honest in the application, there is no use in cutting corners as you might as well just be pulling it out of the sky again!

1. Operating Factor

  • The first factor is the operating factor. How often will the crane be used? Is it for stand-by or maintenance service? Is it for 2,000 hours per year or less, which is the one shift operation, 4,000 hours per year, which is the 2 shift operation, or the 6,000 hours per year, which is the three shift operation
  • Stand-By or Maintenance 5
  • 2000 Hours/Year or less (1 Shift) 8
  • 4000 Hours/Year or less (2 Shifts) 15
  • 6000 Hours/Year or less (3 Shifts) 25


2. Relative Load Factor

  • The next factor to consider is the relative load factor. How does the average lifted load compare to the rated capacity of the crane?
  • Several loads per week at rated capacity 5
  • Several loads per day at rated capacity 15
  • (Majority of loads less than 50% of rated capacity)
  • Several loads per day at rated capacity 25
  • (Majority of loads greater than 50% of rated capacity)
  • Frequent capacity loads per day 35
  • (Majority of loads greater than 50% of rated capacity)

3. Load Impact Factor

  • The load impact factor considers the relative severity of the cranes operation. Is the service low and smooth as in a powerhouse operation? Will the crane be subject to the high impact forces inherent in magnet/bucket service found in steel mills or cement mills? Or does the service fall somewhere in between?
  • Stand-by, Maintenance, Powerhouse 5
  • Warehouse, Machine Shop, Assembly Shop 8
  • Foundry, Hot Metal 15
  • Bucket, Magnet, Grapple 25

4. Relative loss factor (Downtime)

  • The relative loss factor is a measure of the importance of the crane to your operation. If the crane is down for unscheduled maintenance, what is the effect; an inconvenience, a slowdown of operations, or a plant shutdown?
  • Low value on downtime (Inconvenience) 5
  • Medium value on downtime (Slowdown of operation) 15
  • High value on down time (Plant shutdown) 25

5. Ambient Temperature and Environmental Factor

  • Are the ambient temperatures extremely high or low? Or is there a combination of these conditions affecting the crane? The A and E factor considers where the crane is located. Is the environment normal, corrosive or highly contaminated?
  • Normal Indoor or Outdoor Service 5
  • Corrosive, Highly Contaminated Area, or Temperature Extremes 10
  • Corrosive and Highly Contaminated Area 15

6. Maintenance Factor

  • The last factor to consider is the Maintenance factor. While a true preventive maintenance program is ideal, it is very seldom the case.
  • Preventive Maintenance Program 5
  • Normal Maintenance Handled by Maintenance Department but
  • Reactionary other than Lube and minor adjustments 15
  • No In-House Maintenance Capabilities 25
  • This is where you need to add up your points and see where you fall in the matrix key.
  • 0 to 40 Points = CMAA Class “A” and “B”
  • 41 to 65 Points= CMAA Class “C”
  • 66 to 85 Points= CMAA Class “D”
  • 86 to 115 Points= CMAA Class “E”
  • 116 to 150 Points= CMAA Class “F”

I have found over the years there are two areas overlooked or misunderstood the most when determining the classification, the relative loss factor and the Maintenance Factor. If you use this and understand it, it will save you time and possibly money in the future by specifying the correct crane for the application.



Top Running Overhead Crane Runway Systems


Runway Beams:

  • Runway beams and columns for top-running bridge crane applications may be provided by the building supplier or the crane supplier. The design of these beams takes into account the vertical impact of the crane, the lateral force resulting from the effect of moving crane trolleys and longitudinal force from moving cranes. Typical sections include mill shapes and welded built-up plate sections. Support Columns-The columns can be part of the building columns, Independent tie back columns, or an independent column. For new construction the runway system is designed as part of the building. For use in an existing building you have two options.
  • 1) Independent tie back columns that use the building structure to take the horizontal load of the runway system.
  • 2) Independent columns that are freestanding on the foundation or floor, that take the horizontal and vertical loads.

Runway Rail:

  • Runway Rail should be installed in such a manner so that wear to the crane, runway beam supports and the rail itself will be minimized. Rails should be arranged so that joints on opposite runway beams for the crane will be staggered with respect to each other and with respect to the wheel base of the crane. Rail joints should not coincide with runway beam splices. Runway rails should be ordered in standard lengths with one short piece on each side to complete a run. The short piece should not be less than 10′ long. Rail ends will normally be furnished saw cut only, unless otherwise specified by the buyer. Rail ends will normally be furnished with standard drilling for commercial rails splices, unless otherwise specified by the buyer.
  • Common methods of fastening rails to runway beams are hook bolts, bolted clamps, welded stud clamps and welded clamps with a pad. Crane rails should not be painted as this may cause the wheels to slip, resulting in skewing of the bridge and columns.


Overhead Crane Alternatives

Jib Cranes and Gantry Cranes are good alternatives to an overhead crane where a small area is being covered and light loads are being lifted:

The Jib Crane:

  • The Jib crane is a type of crane that has a rotating horizontal boom attached to a fixed support. A standard trolley equipped with electric or hand-geared chain hoist normally operates on the lower flange of the jib crane boom.
  • Jib cranes may be appropriate for servicing machinery located outside of the coverage of an overhead crane, or for assembly lines where jib boom areas can overlap for staged operations.
  • Jib cranes may be floor mounted or supported by the building frame. Floor mounted jib cranes are generally preferred. Jib cranes which must be supported by the building frame may be mounted directly to the building column or mounted to a supplemental column.
  • The floor-mounted jib crane requires no top braces or supports of any kind from the building structure. The jib boom will rotate through a full 360 degrees. Under ordinary conditions, these base-mounted jib cranes can be anchored directly to a properly-designed reinforced concrete floor or separate foundations.
  • The column-mounted jib crane is generally mounted on a building column. The boom rotation is limited to approximately 200 degrees.
  • The application of a column-mounted jib crane requires that the building column, column base anchorage and bracing be designed to account for the special loads imposed by the jib crane. This will usually increase the building column size.

The Gantry Crane:

  • Gantry cranes are adapted to applications where overhead runways would be very long and costly to furnish. They are also appropriate where overhead runways would interfere with handling operations, storage space, or service areas.
  • Single-leg gantry cranes are used in those installations where it is convenient to have one end of the bridge supported on an overhead runway rail and the other end supported on a gantry leg. This design can then utilize adjacent building framing to support the overhead runway rail. This application requires that the building framing, column base anchorage and bracing be designed to account for the special loads imposed by the gantry crane.


Overhead Crane Types

In planning a crane building, and in selecting overhead cranes, it is important to consider future operations that may increase loading and service requirements in addition to present operations. Be certain to plan for both crane building and cranes to satisfactorily meet the increased service conditions that may arise in the future. This planning effort will minimize the possibility of overloading or of placing the structure in a more severe classification than intended.

There are many types of cranes in use today to meet material handling requirements.The types described here include those cranes currently being supplied by major crane manufacturers support of these crane types usually affects the design of the building in which the crane is installed.

Top Running Cranes

Top-running bridge cranes are characterized by bridge end trucks bearing on top rails attached to the runway beams. Top-running bridge cranes are generally used for more severe applications with heavier loads and high service classifications. They are generally applicable when one crane isle extends the full width of a building aisle, and they are frequently used where high travel speeds are required. In comparison to underhung cranes, top-running cranes usually provide greater hook height and clearance below crane girder.
Top-running bridge cranes may be single girder, double girder, or box girder. Single girder cranes are generally used on shorter spans and lower capacities or service classifications. The trolley of a single girder crane is suspended from the girder. Cranes are normally operated by a pendant pushbutton station suspended from an independent track or radio remote.

Double girder cranes

Double girder cranes are generally used on moderate spans and higher capacities or service classifications. The trolley of a double girder crane usually bears on rails attached to the upper flange of the crane girders. Low headroom double girder cranes are available that are designed to produce maximum clearance beneath the bridge.

Box girder cranes are generally used on larger spans and high capacities or service classifications. The trolley bears on rails attached to the upper flange of the crane girders. Box girder cranes are normally operated from a pendant pushbutton station suspended from an independent track or a radio remote.

Underhung bridge cranes

Underhung bridge cranes are characterized by the bridge end trucks being suspended from the lower flange of the runway beam. Underhung bridge cranes are generally used for less severe applications with lighter loads and lower service classifications. They are frequently used where multiple crane aisles are required in a building aisle,where the crane aisle is only a portion of the building aisle, and when materials must be transferred between building aisles. In comparison to top running cranes, underhung cranes usually provide greater hook cover, clearance beneth the runway beam, and clearance for overhead obstructions.

Underhung bridge cranes may be single or double girder with the trolley suspended from the lower flange of the girder or girders. The power source of the hoist, trolley, or bridge may be hand geared or electric. Electric powered cranes are normally operated by a pendant pushbutton station suspended from the hoist.

  • Crane Type Power Source Description Span or Reach Capacity
  • Underhung 1. Hand Geared Single Girder 10’ to 50’ Spans ½ to 10 Tons
  • 2. Electric Single Girder 10’ to 60’ Spans 1 to 10 Tons
  • Top-Running 1. Hand Geared Single Girder 10’ to 50’ Spans ½ to 10 Tons
  • 2. Electric Single Girder 10′ to 60′ Spans ½ to 10 Tons
  • 3. Electric Double Girder 20′ to 60′ Spans 5 to 25 Tons
  • 4. Electric
  • Box Girder
  • Pendant-Operated
  • 4-Wheel End Truck 20′ to 100′ Spans
  • 5 to 25 Tons
  • 5. Electric
  • Box Girder
  • Radio Controlled
  • 4-Wheel End Truck 50′ to 100′ Spans
  • Up to 60 Tons
  • 6. Electric Box Girder
  • Radio Controlled
  • 8-Wheel End Trucks 50′ to 100′ Spans Up to 100 Tons
  • Jib Cranes 1. Hand Geared or Electric Floor-Mounted
  • 280 to 360 8′ to 20′ Reach
  • ¼ to 5 Tons
  • 2. Hand Geared or Electric Column-Mounted
  • 180 8′ to 20′ Reach ¼ to 5 Tons


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

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    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.