Classification and characteristics of gantry cranes

According to the structure of the door frame, it is divided into gantry crane and cantilever gantry crane

Grúa pórtico
1. Full gantry crane: the main girder has no overhang, and the trolley is carried within the main span.
2. Semi-gantry crane: The outriggers have a height difference, which can be determined according to the civil engineering requirements of the site.

Cantilever Gantry Crane
1. Double cantilever gantry crane: The most common structural form, the force of the structure and the effective use of the site area are reasonable.
2. Single cantilever gantry crane: This structural form is often selected due to site constraints.

According to the main beam form
1. Single girder gantry crane
The single main girder gantry crane is simple in structure, easy to manufacture and install, and its own weight is small. Most of the main girder is a partial rail box frame structure. Compared with the double girder gantry crane, the overall rigidity is weaker. Therefore, this form can be used when the lifting capacity Q≤50t and the span S≤35m. There are two types of L-shaped and C-shaped gantry legs for single girder gantry cranes. The L-type is easy to manufacture and install, has a good stress condition, and its own mass is small, but the space for hoisting goods through the outriggers is relatively small. The C-shaped leg is made into an inclined or curved shape, and the purpose is to have a larger lateral space so that the goods can pass through the leg smoothly.

2. Double girder gantry crane
The double main girder gantry crane has strong bearing capacity, large span, good overall stability and many varieties, but its own quality is larger than that of the single main girder gantry crane with the same lifting capacity, and the cost is also higher. According to the structure of the main girder, it can be divided into two forms: box girder and truss. At present, box-shaped structures are generally used.

According to the main beam structure

1. Viga de armadura
La forma estructural soldada mediante ángulo de acero o viga en I tiene las ventajas de bajo costo, peso ligero y buena resistencia al viento. Sin embargo, debido a los muchos puntos de soldadura y los defectos de la propia armadura, la viga de la armadura también tiene las desventajas de una gran deflexión, baja rigidez, confiabilidad relativamente baja e inspección frecuente de los puntos de soldadura. Es adecuado para sitios con menores requisitos de seguridad y menor capacidad de elevación.

2. Viga cajón
La placa de acero está soldada en una estructura de caja, que tiene las características de alta seguridad y alta rigidez. Generalmente se utiliza para grúas pórtico de gran y gran tonelaje. Como se muestra en la imagen de la derecha, la MGhz1200 es la grúa pórtico más grande de China con una capacidad de elevación de 1200 toneladas. La viga principal adopta una estructura de viga cajón. La viga cajón también tiene las desventajas de su alto costo, gran peso y poca resistencia al viento.

3. Viga alveolar
Generalmente se refiere a "viga en forma de panal triangular isósceles", la cara final de la viga principal es triangular, hay orificios en forma de panal en el vientre oblicuo en ambos lados y hay cuerdas en las partes superior e inferior. La viga de panal absorbe las características de la viga de armadura y la viga de cajón, y tiene mayor rigidez, menor deflexión y mayor confiabilidad que la viga de armadura. Sin embargo, debido a la soldadura de placas de acero, el peso propio y el costo son ligeramente más altos que los de las vigas de celosía. Es adecuado para sitios o patios de vigas que se utilizan con frecuencia o tienen una gran capacidad de elevación. Dado que este tipo de viga es un producto patentado, hay menos fabricantes.

by purpose
1. Grúa pórtico ordinaria
This kind of crane mostly adopts box type and truss type structure, which is the most widely used. It can carry various pieces and bulk materials, with a lifting capacity of less than 100 tons and a span of 4 to 39 meters. Ordinary gantry cranes with grabs have a higher level of work. Ordinary gantry cranes mainly refer to hook, grab, electromagnetic, hoist gantry cranes, and also include semi-gantry cranes.

2. Gantry cranes for hydropower stations
It is mainly used for lifting and opening and closing gates, and can also be used for installation operations. The lifting capacity is 80-500 tons, the span is small, 8-16 meters; the lifting speed is low, 1-5 meters per minute. Although this kind of crane is not frequently lifted, once it is used, the work is very heavy, so the work level should be raised appropriately.

3. Shipbuilding gantry cranes
It is used to assemble the hull on the berth, and there are always two lifting trolleys: one has two main hooks, running on the track of the upper flange of the bridge; the other has a main hook and an auxiliary hook, which is on the lower flange of the bridge run on rails for flipping and hoisting large hull sections. The lifting capacity is generally 100-1500 tons; the span is up to 185 meters; the lifting speed is 2-15 meters per minute, and there is also a fretting speed of 0.1-0.5 meters per minute.

4. Grúa pórtico para contenedores
For container terminals. After the trailers transport the containers unloaded from the ship by the quay wall container carrier bridge to the yard or rear, they are stacked by the container gantry crane or directly loaded and transported away, which can speed up the turnover of the container carrier bridge or other cranes. The yard that can stack containers with a height of 3 to 4 layers and a width of 6 rows is generally of the tire type, but also of the rail type. Compared with the container straddle truck, the container gantry crane has a larger span and height on both sides of the portal frame. In order to meet the transportation needs of the port terminal, this kind of crane has a higher working level. The lifting speed is 8-10 meters per minute; the span is determined by the number of rows of containers that need to be crossed, and the maximum is about 60 meters, corresponding to the lifting capacity of 20 feet, 30 feet, and 40 feet long containers, which are about 20 tons and 25 tons respectively. and 30 tons.