Overall installation safety of the hottest tower c

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Safety of overall installation of tower crane

taking QT 3-8 tower crane as an example, this paper introduces the method of overall lifting the tower body. This method is applicable to the situation that there is no large lifting equipment and a suitable construction site. Change the work of installing the tower body from working at heights to assembling on the ground and then lifting it as a whole

(1) preparatory work

check whether the subgrade and track laying meet the requirements, bury the ground anchor, and determine the location of the ground anchor according to the rotation and lifting direction of the tower and the total height of the tower. Ground anchors are divided into main ground anchors and auxiliary ground anchors. The main ground anchor is the key to the erection of the tower body. All the loads of rotating and lifting the tower body are borne by the main ground anchor, and the ground anchor is still needed when dismantling the tower, so it must be carefully buried to make it reach the required bearing capacity, and anti-corrosion treatment should be done. The center of the anchor wheel must be consistent with the center of the gauge, so as to ensure that the tower can always return automatically after the end of the experiment; The central surface of the track gauge rotates without eccentricity, so that the gantry is evenly stressed. The function of the auxiliary ground anchor is to loosen the steel wire rope with rotation when the tower is lifted. This anchor is used as the anchor point of the safety steel wire rope to prevent the tower from falling in the opposite direction during the rotation of the tower

(2) overall installation

according to the procedures required in the instructions, install the traveling mechanism, gantry and pressure iron. The jib is inserted into the support shaft of the gantry platform, and the rail crib is erected according to the assembly size of the tower body lying down. The tower body and tower cap are assembled so that the tower body is erected on the rail crib, and its axis is roughly parallel to the ground

(3) thread the steel wire rope

pass the steel wire rope of the winch through the pulley block from the cab to the tower cap, and finally fix it on the head of the crane. All the rope lengths and the distance between the two pulley blocks should be determined by calculation

(4) before erecting the tower,

check the controller, limit switch and other electrical equipment, remove the movable control panel in the control room and install it on the outdoor support to facilitate the operation when erecting the tower

clamp the rail clamp and wedge the anti-skid wedge under the walking wheel on January 9, 2015

in order to strengthen the rigidity of the gantry, cross braces can be tied on both sides of the gantry with a year-on-year increase of 8.3%

before starting, the responsibilities of each post should be specified, and the division of labor and command contact signals should be strictly enforced. Experienced lifting personnel shall be responsible for the supervision of the main anchor. When abnormal phenomena such as looseness are found, the company shall immediately stop the car that starts late and take measures (pressing iron can be added to the anchor)

start the winch to make the tower body about 200mm away from the track pile, stop the machine immediately and check the stress condition of all parts

(5) erect the tower

after inspection, it is confirmed that the condition is normal, continue to start the winch to make the tower stand stably, and the steel wire rope at the auxiliary ground anchor will loosen

after the tower is erected to 60 °, the winch should gradually slow down with the change of the tower center of gravity. When the tower center of gravity is close to the installation hinge, the winch stops working, uses the mobile crane to tighten the safety wire rope, and slowly falls on the pre padded skid by the weight of the tower. After the tower is stable, tighten the safety wire rope to make the tower slightly crooked, then remove the skid layer, and then loosen the safety wire rope to stabilize the tower

(6) install other components

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