Crane Girder Designs:Single vs Double Girder, Beam & Box Girder
What is a crane girder? A crane girder is a preformed metal beam on which the crane trolley or hoist of a travelling overhead crane moves.Crane girder can be grouped into overhead crane girder and gantry crane girder. The designs of overhead crane girders can be divided into single girder and overhead crane in terms of numbers of girder beams, and box girder, H beam and Chinese style girder in terms of crane structure. While the designs of gantry crane girders can be divided into single girder and double girder in terms of number of crane beams, box girder, truss girder & H beam girder in terms of crane girder structures.
Girder design of overhead cranes
Overhead cranes can be segregated under two categories based on the number of cross –girders and based on the nature of running.
Based on the number of cross- girders, overhead crane can be categorized as single girder and double girders.
- Single girder design - with one box girder or H beam as the main bridge of overhead crane with capacity from 500 kg -35 ton based on customized designs.
- Double girder design - with 2 box girder as the the main bridge of overhead crane with capacity from 5 ton to 75 ton and from 5 ton to 320 ton with process crane designs.
Overhead crane configuration has under running and top running cranes (based on nature of running).
- Under running :Running on the bottom flange of runway girders, the running cranes are supported from the roof structure. They are advantageous since the very small trolley approach dimension can utilize the maximum of the building's width and height. There is a possibility of using the existing ceiling girder for protecting the crane track. Capacity of under running overhead crane is up to 10 ton.
- Top running:The top running overhead crane, which has a fixed track system installed on the top of each runway beam, is the most widely utilized crane type.Top running overhead cranes: 2.5 -20 ton single girder & 5 -550 ton double girder top running crane design for you. Get Top running bridge crane design drawing now!
Single girder design of overhead crane
Single girder overhead cranes can be of designed with the following types of main girders:
- I beam - I-beam type main crane girder which has a crane span of 18m(59 ft) and load up to 10 tonnes
- Box girder - Box-type main crane girder which spans up to 30m (98 ft) and can uplift load up to 35 tonnes
- Under running -Under running single girder cranes which span up to 22m (72 ft) and weight lift load up to 10 tonnes.
Box girder
Chinese style box girder
I Beam girder / H beam
Double girder design of overhead crane
The most common form of girder structureutilized by overhead cranes is the box-type girder structrue. The upper and lower cover plates, as well as two vertical cover plates, make up the box crane girder, which is made up of closed box-shaped section constructions. The lower border of the web and the lower cover should be formed of parabolic shape to minimize weight and provide an equivalent strength beam. However, to make manufacture easier, the web is normally rectangular in the middle and trapezoid on both sides, allowing the lower cover to be tilted at both ends.
Usually, the top running double girder overhead crane is usually adopts box shaped girder design for heavy duty material handling with capacity from 5 ton to 320 ton.
As for the under-hung double girder overhead crane also can be designed for heavy loads handling with capacity up to 10 tons, which usually is designed with H beam or I beam.
Box girder design of overhead crane
Crane girder mainly use box-type structure and truss structure, while the box-type structure crane girder is the most widely used.
The entire steel plate welding can be used on the box-type crane girder, making active and semi-active welding simple. It has the advantages of easy planning, good fabrication technology, and batch production suitability. It is the most extensively utilized method of construction.
Box girder & i beam girder design
Box girder design
Box girder & box beam double girder design
Box girder & box beam design
Box girder & box beam design
Double Girder box girder & box beam design
Crane girder designs of gantry cranes
Overhead gantry cranes can be segregated under two categories based on the number of cross –girders and based on the nature of running.
- Based on the number of cross- girders it can be categorized as single and double girder gantry cranes.
- Based on construction of girder structure, it can be box girder,I beam girder, truss girder, & honey comb beam gantry cranes.
- For single girder crane design, the structures of gantry crane girders can be box girder, truss girder and I beam girder.
- For double girder crane design, the structures of gantry crane girders are usually box girder, truss beam and honeycomb beam.
Box girder of gantry crane
Gantry crane box girder is mainly made of steel plate welded into box structure, which has the advantages of high safety and reliability, stiffness and other advantages, but the box girder structure of the gantry crane has the features of high cost, heavy dead weight, and relatively poor wind resistance.
Truss girder of gantry crane
The truss beams of gantry crane are typically fabricated by welding the I-beams. The truss has the advantages of low cost, light weight, and strong wind resistance, but it also has the disadvantages of a large surrounding degree and low stiffness due to many welding points and truss defects, low security and stability, the necessity for frequent testing of solder joint and other flaws. Click to read more about truss girder gantry crane.
Single girder gantry crane with truss girder design
Double girder gantry crane with truss girder design
Differences between box girder and truss girder
Under the same conditions, the truss crane girder is less stronger than the box structure crane girder , but the truss crane girder is easy to show stress concentration and even crack
- Box crane girder relatively heavier than truss girder.
- Box crane girder is easy to manufacture
- Boxcrane girder can use angular bearing box, connected with the end of the beam stress concentration, easy to crack
Honeycomb girder of gantry crane
What is honey comb girder of gantry crane ? The honeycomb beam's primary face is an isosceles triangle, with honeycomb perforations on both sides of the waist and upper and lower chords. Honeycomb beams have the benefits of truss girders and box girders, but because they are welded with steel plates, they have a higher dead weight and cost than truss beams.
Single honeycomb girder of gantry crane
Double honeycomb girder of gantry crane
Structure of gantry crane I beam / H beam girder
As for the i beam / H beam gantry crane, it is usually used for light duty gantry crane working with electric chain hoist or wire rope hoist for light duty material handling. I beam girder design are usually used in single girder hoist gantry crane & small portable gantry cranes.
Single girder gantry crane with I beam girder design
Steel material for overhead crane girder manufacturing
During our interactions with clients, we've found that some of them have specific preferences for crane steel materials. Here's a quick rundown of the two types of steel that will be utilized in our cranes.
Steel materials Q235 and Q355 are commonly employed in the production of our cranes.
The difference of the 2 kinds materials:
The yield strength: | alloy content | |
Q235 steel | 235MPa | Carbon structural steel |
Q355 steel | 355MPa | Low alloy structural steel |
- Q235—Metal structural parts, low-core-strength carbonized or cyanide parts, tie rods, connecting rods, hooks, couplings, bolts and nuts, sleeves, shafts, and welded parts.
- Q345—Good overall mechanical properties, good low-temperature performance, good plasticity and weldability, as metal structural parts for medium and low-pressure containers, oil tanks, vehicles, cranes, mining machinery, power plants, bridges and other structures, mechanical parts, and building structures that bear dynamic loads, hot-rolled or normalized use, can be used for various structures in cold areas below -40 °C.
Customer can choose the steel material they want according to the working demands:
- The Q355 steel plate will be the ideal choice for the client if the material handling cranes are working in low-temperature areas, or if the overhead crane's working class is very high (such as A6 or A7, A8 in ISO standard), or if the crane structure is rigidly controlled.
- If the customer has no special needs, they can opt for Q235 steel plate, which is likewise extremely good in application and costs less than Q355.
If you have any special requests on crane steel, please feel free to contact us. We have extensive expertise in crane design, production, and supply to customers in China and abroad, and we will provide the best solution for each customer!
Steel materials for overhead crane, gantry crane, jib crane fabrication
Crane girder manufacturing
As for crane girder manufacturing, it main goes the following procedures:
- Pre - treatment of steel surface to remove the rust by shot blasting and ball blasting to ensure steel plates are in compliance with the national standards.
- Primer Painting to protect steel from rust to ensure after shot blasting and ball blasting
- Precision marking of steel plate with sample plate,diagram or handrail to ensure the accuracy
- Accurate steel plate-cutting by CNC cutting, semi-automatic cutting, shearing and sawing to ensure the dimension exactly as required.
- Plate welding by semi-automatic cutter and automatic submerged-arc welding to ensure quality of welding part.
- Flaw detection by ray and ultrasonic to detect the flaw of weld seams to ensure seam quality
- Leveling: Level the steel plate after connecting.
- Secondary marking & cutting: To mark and cut the steel plate with the required shape and size
- Assemble: All the assembly should be serious conducted according to the general crane drawing with exact specifications and configurations.
- Flaw detection to detect the weld seams of main parts to ensure quality of welding
- Assembly (assemblage)to assemble each part as required with high accuracy and right operation
Advanced crane testing equipment in our hoist and crane factory
Advanced crane testing equipment in our hoist and crane factory
Advanced crane testing equipment in our hoist and crane factory
Advanced crane testing equipment in our hoist and crane factory
Advanced crane testing equipment in our hoist and crane factory
Advanced crane testing equipment in our hoist and crane factory
Advanced crane testing equipment in our hoist and crane factory
Advanced crane testing equipment in our hoist and crane factory
As a crane manufacturer, we can supply customized crane girders, single crane girder, double crane girder, box girder, Beam girder or truss gantry girder, etc. More information about crane girder manufacturing, please read on How to manufacture crane girder or Contact us to by leave a message down below.
Storage workshop of overhead crane girders
Division & connection of overhead crane girder
Overhead crane girder division andoverhead cranegirder connection. Due to the length of overhead crane girder andeot cranegirder is too long to be transported, the crane girder is designed into 2 or 3 sections, which is called crane girder division and the crane girder has to be connected when installation.
Why to devide overhead crane girder?
Crane division for the sake of transportation. Due to the crane girder is long and heavy, the transportation plan will be decided beforehand. For overhead crane girder with long length, the crane girder can be fabricated into two or three parts, when necessary, which can be assembled or connected at the installation site.
Traffic rules of destination countries. Because different nations have different traffic laws, it is best to clarify the truck length limit with the traffic department before fabricating the crane girders. The largest truck in China is 17.5 meters, and it can transport crane girders up to 30 meters in length. We just delivered a crane with a 32-meter girder a few days ago.
Cargo handling capacity of ports.Another thing to keep in mind is that certain ports have cargo handling capacity limits; for example, the port may not be able to handle crane girders longer than 30 meters; therefore, in addition to confirming the traffic limit, knowing the port information is critical.
How to connect the overhead crane girder?
How are the girderof an overhead crane separated and connected? Overhead crane engineers calculate the design of crane girder sections using a variety of theories and procedures. Please contact our engineer or leave a message below if you have any questions. The overhead crane girder connection will be illustrated in the following part for your convenience.
Crane girder connection
Crane girder assembly
Crane girder installation
Safety on crane division & connection on crane girder
Misconception on the divided crane girder.Is is safe to use the divided crane beam girder? The answer is positive. Yes, the division of crane girder is well and carefully calculated and designed which will ensure the efficiency and safety of the overhead crane. Actually crane girder division for transportation convenience is technically allowed and will not affect the performance of cranes. We have experienced too many cases with divided girders, so please do not let this worry prevent you going forward.
Crane girder transportation
As for crane girder transportation, the following ways are optional according to your specific conditions:
- Crane transport by sea : LCL: less than container load , FCL: full container cargo load , Bulk cargo ship
- Crane transport by railway: The most appropriate crane transportation schema will be recommended based on the overall condition of the cranes, such as the size, weight, and destination of the material handling. In the meantime, the crane buyers' comments and choices are fully recognized.
Transportation advice for crane girders
The transportation plan will be established ahead of time due to the crane beam's length and weight. Before crane production, the clients will choose the following solution for crane beam transportation:
- Fabricate the entire girder when the crane's length isn't as long.
- Fabricate the girder, if necessary, in two or three segments that may be assembled on site.
Please see Crane Transportation & Delivery for further information on crane girder transportation.
Article by Bella ，who has been in the hoist and crane field since 2016. Bella provides overhead crane & gantry crane consultation services for clients who need a customized overhead travelling crane solution.Contact her to get free consultation.
