Let's take a look at some knowledge points about hoisting cages.


Release time:

Oct 09,2021

Let's learn about some knowledge points about hoisting cages. There are four main hoisting conditions for hoisting cage, and the main and auxiliary hoists have different forces under each working condition. Lifting condition 1: under this condition, the main crane and the auxiliary crane will horizontally lift the lifting cage made on the lifting cage platform, and the weight of the lifting cage will be borne by the main crane and the auxiliary crane at the same time. As the center of gravity of the hoisting cage deviates to the main hoisting side of the hoisting cage center, the main hoisting force is larger and the auxiliary hoisting force is smaller.

Let's take a look at some knowledge points about hoisting cages.


吊装笼

There are four main hoisting conditions for hoisting cage, and the main and auxiliary hoists have different forces under each working condition.

Lifting condition 1: under this condition, the main crane and the auxiliary crane will horizontally lift the lifting cage made on the lifting cage platform, and the weight of the lifting cage will be borne by the main crane and the auxiliary crane at the same time. As the center of gravity of the hoisting cage deviates to the main hoisting side of the hoisting cage center, the main hoisting force is larger and the auxiliary hoisting force is smaller.

Hoisting working condition 2: under this working condition, the force of the main crane and the auxiliary crane changes continuously, while the force of the auxiliary crane increases gradually until the auxiliary crane no longer bears the force, and the weight of the hoisting cage is completely borne by the main crane. However, in the actual construction process, this working condition is dynamic, and the actual force situation has a great relationship with the position, angle and rotation direction of the crane, and the force situation is complex.

Hoisting condition 3: under this condition, the auxiliary crane is separated from the hoisting process, and the main crane completely bears the weight of the whole hoisting cage, and the hoisting cage is transported to the slot section where the hoisting cage needs to be sunk through the construction road. In this condition, because the crane needs to travel with load, the lifting weight of the crane should be within 70% of the large design lifting weight. In order to obtain a large lifting capacity, it is necessary to control the turning radius of the crane to be small. So as to ensure the safety of hoisting cage transportation.

Hoisting condition 4: under this condition, the upper and lower hoisting cages shall be connected at the notch, and the total weight of the upper and lower hoisting cages shall be borne by the main crane. Under this working condition, part of the hoisting cage has entered the tank, and the buoyancy of the mud to the hoisting cage is not included. Moreover, the crane is in a non-walking state, so the lifting weight of the crane should be controlled within 80% of the designed lifting weight.

The unfavorable working condition of the main crane is working condition 4, in which the total weight of the upper and lower hoisting cages connected is borne by the main crane. The unfavorable working condition of the auxiliary crane is working condition 2, and the large lifting weight is 60% of the weight of the hoisting cage and the sling.

So what are the matters needing attention in hoisting cage hoisting?

1. Safety alarm in the lifting area

During the hoisting operation, a warning area shall be set up in the hoisting area, and the warning area is mainly under the lifting object and the boom. Warning signs shall be set up near the hoisting area, and special personnel shall be assigned for safety warning to prevent other personnel from approaching the warning area during hoisting operation. No person shall stay, work or pass under the jib and heavy objects while the crane is working.

Safety in Special Environments

It is forbidden to engage in outdoor hoisting operations in severe weather such as strong wind and fog above level 6. After the bad weather, all safety facilities should be checked one by one. If they are loose, deformed, damaged or falling off, they should be repaired immediately. During night construction, sufficient lighting equipment must be installed to ensure the brightness of night hoisting, and command tools with reflective materials must be used to facilitate night identification. 3. Technical guarantee

Before the hoisting cage is made, check the actual width of the unit groove section and the size of the formed steel bar. Only when there is no difference can it be made on the platform. For the groove section with closed width, the width of the groove section should be measured again in advance, and the width of the lifting cage should be adjusted according to the actual width. The hoisting cage must be welded in strict accordance with the design drawings to ensure the length and quality of the weld. The welding quality of reinforcement shall meet the design requirements. Reinforcement for lifting climbs and lifting points shall be fully welded. The main reinforcement and horizontal reinforcement shall be connected by spot welding. The welding quality shall be strictly controlled around the hoisting cage and within 1m above and below the hoisting point. When the hoisting cage is just lifted off the platform, stop lifting and observe whether there is any abnormal phenomenon. If there is any, welding and reinforcement shall be carried out immediately. According to the specification requirements, the flatness of the top surface of the guide wall is 5mm. Before hoisting the cage, the elevation of the four fulcrums on the guide wall shall be reviewed, and the length of the steel hanger shall be accurately calculated to ensure that the error is within the allowable range. After the hoisting cage is lowered into place, the steel hanger will become longer due to the inconsistency between the hoisting point and the measuring point, which will affect the elevation of the hoisting cage. In order to ensure the elevation of the joint, the elevation of the cage top of the hoisting cage should be measured immediately with a level gauge, and adjusted to the design elevation according to the actual situation. When the hoisting cage is hoisted into the groove, forced impact into the groove is not allowed. At the same time, pay attention to the surface of the foundation pit and the adjacent soil surface of the lifting cage. It is forbidden to put it upside down. The channel steel at the rest point must be welded according to the measured guide wall elevation. For the hoisting of special-shaped hoisting cage, the position of the hoisting point shall be reasonably arranged to avoid deflection, and the welding quality inspection shall be strengthened in the process to avoid missing welding spots.


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