According to the principle of “fast or slow”, the lifting height and arrival time of the tower top shall be uniformly determined according to the project progress.
Calculation of height difference of jib crossing not greater than 1 / 2 of jib length: △ H / = hg-hd + HJ ≥ BH + HF + D = 4.5 ⑵.
Among them, the cross length of 7# tower and 8#/ 11# tower is greater than 3 / 4; 13 #, 10 # / 12 # tower; 6#, 7# towers may collide.
The 7# tower crane is provided with a supporting wall, and the height of the supporting wall is 6 floors, that is, one supporting wall is set on the 6th floor.
For example, article 10.5 of safety code for building tower cranes (gb5144-2006) stipulates that “the vertical distance between the lowest position of the high-level crane (the balance weight of the hook rising to the highest point or the highest position) and the highest position part of the low-level crane shall not be less than 2m”.
Each tower crane must complete the jacking as scheduled according to the correct height and time without advance or delay.
Therefore, the height difference of tower crane must be calculated reasonably.
The control of safety height difference is to ensure the safety of tower groups; The height difference is too small, which may cause the collision between the hook of the high-level tower and the jib of the low-level tower crane; The height difference is too large.
One attached wall is set on the 5th, 11th, 17th and 23rd floors respectively, and the 10 #/ 12 # tower is installed as an independent height.
When designing the construction scheme of vertical transportation, special attention must be paid to the control of the safe height difference of the tower crane.
When using the tower crane, the project progress shall be reasonably arranged to ensure that the tower crane with interference in the rotation range maintains sufficient height difference when jacking and adding sections.
6# tower and 1# tower are forbidden to swing the boom to the top of adjacent buildings for construction.
The newly issued technical code for safety use of construction machinery Jgj33-2012 section 4.4 Article 22 stipulates: “when there are more than two tower cranes at the same construction site and may interfere with each other, the group tower operation scheme shall be formulated; the minimum erection distance between the two tower cranes shall ensure that there is at least 2m distance between the jib end of the low tower crane and the tower body of another tower crane, which is at the lowest part of the high tower crane (the hook is opened to the highest point or the lowest part of the balance arm) the vertical distance between the hook and the highest position in the low-level tower crane shall not be less than 2m ” (as shown in the figure below).
The commonly used parameters for calculating the height difference of tower crane are: ① tower foundation height difference HJ; ② tower crane lifting section height BH; ③ tower crane cap height TM; ④ height Hg and HD from the lifting boom of high and low tower cranes to the top surface of foundation; ⑤ installation height difference of lifting boom of high and low tower cranes △H。 In the vertical design of tower group layout, the reasonable determination of tower crane height difference parameters is divided into the following three cases: ⑴.
1.
Due to the continuous sorting of towers, it may cause chain reaction and potential safety hazards.
The lifting of tower ceiling shall comply with the requirements of safe distance.
What is the safe distance between the towers? 1、 Calculation of various safety distances and simultaneous operation of tower cranes shall not only make the tower crane give full play to its due work efficiency, but also ensure the construction safety.
2.
Jib crossing greater than 1 / 2 of jib length, Calculation of height difference less than 3 / 4 of the jib length: △ H / = hg-hd + HJ ≥ TM = 7 ⑶ calculation of height difference of jib crossing greater than 3 / 4 of the jib length (or covering the lower tower body): △ H / = hg-hd + HJ ≥ TM + 2m = 91# tower crane and 7# tower crane do not cross, and 1# tower crane and 6# tower crane belong to the case of jib crossing not greater than 1 / 2 of the jib length, 7 #/ 12 # tower crane and 10 #/ 12 # tower crane belong to the situation that the boom crossing is not more than 1 / 2 of the boom length, 10 # / 12 # tower crane and 6 # tower crane belong to the situation that the boom crossing is not more than 1 / 2 of the boom length, 13 # tower crane and 10 #/ 12 # tower crane belong to the situation that the boom crossing is not more than 3 / 4 of the boom length, 8 #/ 11 # tower crane and 10 # / 12 # tower crane belong to the situation that the boom crossing is not more than 3 / 4 of the boom length, 1 # tower crane and 2 # tower crane belong to the situation that the boom crossing is not greater than 1 / 2 of the boom length, 2 # tower crane and 8 # / 11 # tower crane belong to the situation that the boom crossing is not greater than 1 / 2 of the boom length, and 13 # tower crane and 8 # / 11 # tower crane belong to the situation that the boom crossing is not greater than 1 / 2 of the boom length; 6# tower crane and 7# tower crane belong to the situation that the boom crossing is not more than 3 / 4 of the boom length; 2 # tower crane and 7# tower crane belong to the situation that the boom crossing is not greater than 1 / 2 of the boom length; 7 # tower crane and 8 #/ 11 # tower crane belong to the situation that the boom crossing is greater than 3 / 4 of the boom length.
If the plane position cannot be staggered, it shall be staggered vertically, and the staggered distance shall meet the requirements of the previous article by 10m.
Determine the height difference calculation parameters and reasonable height difference values.
Try to avoid the collision between the tower crane jib and the pull rod and balance arm of another tower crane through the height difference of the tower crane, so as to meet the safe height.
3、 According to the actual situation of the project, the first bid section 2# tower, 8#/ 11# tower and 13# tower of China Construction Fifth Engineering Bureau shall be constructed first; The continuous construction of the four construction blocks of 1 # tower, 6 # tower, 7 # tower and 10 #/ 12 # tower is delayed for five months, and the seven tower cranes must be staggered and lifted according to the height difference of the design scheme.
In the current regulations, many regulations stipulate the height difference of tower crane.
4 attached walls are set for 1 #, 6 # towers, with the height of 6 floors as an attached wall height.
Therefore, the following steps can be referred to determine the reasonable height difference value.
3.
II.
This is the minimum height difference requirement.
List of overlapping range of tower crane it can be seen from the data in the above table that 7# tower crane boom length is reduced to 37m, which is staggered with the plane position of adjacent tower cranes, which can meet the safety distance.
When the height of tower body and adjacent buildings cannot meet the safe distance, limit measures must be taken for the rotation range of tower crane..
