Main application scenarios at the construction site: hoisting and hoisting mechanical slings, profiled steel pick-up unloading wire ropes, cantilevered operating platforms, etc. Then in different application parts, how are the wire rope diameters, the number of rope clips, the spacing and the direction specified?

1. Sectional steel cantilever scaffolding

The relevant provisions of Article 6.10 in the "Safety Technical Specification for Fastener Type Steel Pipe Scaffolding in Construction" (JGJ130-2011):

It is clear: the unloading of the wire rope is a structural requirement, the nominal diameter is not less than 14, and the number of rope clips should not be less than 3.

Note: In case of special circumstances, when the load of the frame body is large, it is necessary to consider that the steel wire rope participates in the force calculation.

2. Cantilevered operating platform

Article 6.4.7 of "Technical Specifications for Safety of Construction at Heights" (JGJ80-2016):

Appendix C and related provisions explain:

Clear: The nominal diameter of the wire rope should be determined according to the calculation, and the rope clamp should match the diameter of the wire rope. And the rope clip shall not be less than 4.

3. Tower crane

Article 6.2 of "Safety Technical Regulations for Installation, Use and Disassembly of Construction Tower Cranes" (JGJ196-2010):

So, how many rope clips does the wire rope need? What is the principle of rope clip spacing and direction? Here: "Wire Rope Clip" (GB5976-2006), which is the most fundamental basis.

Look at each sentence in the picture above!

in conclusion:

1. The number of rope clips matches the nominal diameter of the wire rope, and there are no less than 3 wire rope clips for the steel pick-up frame because, according to the structure, the diameter of the pick-up wire rope is not less than 14 (generally 14) and less than 18. The calculated nominal diameter of the wire rope of the cantilever operating platform is generally greater than 18, so there are no less than 4 rope clips. The final actual number of rope clips can be found in the table according to the diameter.

2. Rope clip spacing: generally 6 to 7 times the nominal diameter of the wire rope;

3. The direction of the rope clip: the direction is as shown in the above figure, the U-shaped bolt of the rope clip is buckled at the end of the wire rope ( that is, the side of the rope head ), and the clip seat is in the working section. All rope clips are in the same direction and must not be staggered.

Attachment: Defect Judgment and Scrap Standard for Hoisting Wire Rope and Sling

1. Defect: steel wire extrusion treatment: scrapped immediately

2. Defect: single-strand steel wire rope core extrusion treatment: immediately scrapped

3. Defects: Depression of rope strands, local reduction of rope diameter Processing: Check or reduce the load

4. Defect: strand extrusion/twisting treatment: scrapped immediately

5. Defects: partial flattening treatment: scrapped immediately

6. Defect: kink (forward) Treatment: scrapped immediately

7. Defect: kink (reverse) Disposal: scrapped immediately

8. Defects: strand extrusion/twisting treatment: inspection, load reduction, serious scrapping

9. Defect: Cage Distortion Treatment: Scrap immediately

10. Defects: External wear treatment: lubrication, observation,

11. Defects: Depression of rope strands, rope treatment: scrapped immediately

12. Defects: surface broken wire treatment: 2 broken wires within a twist pitch or 10% broken wires are scrapped

13. Defect: Protruding inner strands Treatment: Scrap immediately

14. Defect: Local diameter becomes larger Treatment: increase by 5%, immediately scrapped

15. Defects: partial flattening treatment: scrapped immediately

02How to use the shackle

Taking our commonly used U-shaped shackle as an example, for the convenience of explanation, the composition of the shackle is defined as follows, as shown in the following figure:

We know that shackles are the most commonly used rigging. They are necessary for hoisting and are used most frequently. Shackles are relatively simple, but they are also more prone to problems. At present, there are three main ways to use shackles:

The first

1. Binding method of pocket rope: the binding method of passing the sling through the bottom of the heavy object and hanging the rope end on the hook. This method is mainly suitable for packing equipment or equipment with relatively regular shapes.

the second

the third

Which of the three ways is right and which is wrong?

Let's explain the first one one by one. The shackle is subjected to lateral force. We say that this method of use is wrong. The correct force of the shackle is shown in the following figure:

The first way of stress is that the force of the wire rope acts on the buckle body, which is very easy to cause the deformation of the shackle, thereby causing the hanging object to fall off (due to the limited test tools, it is impossible to show the picture of the final pulling and deformation of the shackle).

In the second way of stress, in the process of pulling the wire rope, the frictional force of the wire rope acting on the shackle pin shaft is very easy to turn the pin shaft out, so that the hanging object falls off and is dangerous.

The third way of stress is that the pin is at the fixed end, and there is no rotation during the lifting process, which ensures the tightening of the shackle connection, so it is correct.

03Excellent practice of bucket wire rope

There are 4 wire rope clips for the bucket, and the direction is set correctly

The inner side of the bucket wire rope is provided with a heart ring and a shackle to prevent the wire rope from being worn

Bucket wire rope length over 30cm

(When the steel wire rope is fixed by braiding, the length of the braided part shall not be less than 20 times the diameter of the steel wire, and shall not be less than 300mm)

04 Hoisting and bundling, there are usually three methods

2. Binding method with rope: the method of tying the sling out of a rope loop with a snap ring, and then tying the rope loop to lift heavy objects. When the rope binding method is used, the rope is generally passed under the heavy object, and then the rope end and the middle section of the rope are connected with a clamping rod. The middle section of the rope can move freely in the clamping ring. When the binding rope is stressed After that, the rope loop has a tightening force on the weight at the binding point. When the weight reaches the vertical level, the binding rope will not slip on the surface of the weight.

3. Binding method of clasp connection: use the clasp to connect the rope end of the sling with the lifting ring and lifting lug on the heavy object to carry out the binding method of lifting the heavy object. This method is often used in the bundling of lifting lugs or lifting rings, and heavy objects. According to the number of lifting ears or lifting rings on the heavy objects, the corresponding number of clamping points is used.

05 Summary of common unqualified photos of steel wire rope (real version)

The specification and model of the steel wire rope should meet the requirements of the tower crane operating manual, be well lubricated, and have no friction with the metal structure. The wire rope shall not be deformed such as kinks, flattening, bending, broken strands, cage-like distortion and broken cores, and shall not be severely worn. (The diameter shall not be reduced by less than 7%, and the number of broken wires shall not be greater than 10% of the total number.)

bending

broken wire

single broken wire

Broken core

Rust

Flattening, kinking, cage distortion (scattered strands)

cage deformation

knot

Untidy and squashed ropes

broken wire

cage deformity

squish

Broken stock

The rope is not neat

Broken core

cage deformity

bending

broken wire

Broken stock

cage deformation

The main rope is an item that must be checked for inspection. If it is not qualified, it can be judged that the tower crane installation is not qualified. Please do your own research.