Tower crane; Buildings; hinder
With the rapid development of the construction industry, tower cranes (hereinafter referred to as tower cranes) are widely used and play an important role in construction projects. The safe use and management of tower crane is particularly important. Here, I want to talk about the safe use of tower cranes in some special occasions. In some construction sites, the site is narrow, and after the tower crane is installed, the boom fights with the buildings around the new building in the process of rotation, which brings great hidden dangers to the safe use of the tower crane. In view of this situation, the crane boom should be shortened according to the requirements of the manual, so that the minimum distance between the crane boom and the surrounding buildings is not less than the safe distance. If the boom is shortened according to the instructions, the safe distance can't be reached. In order to ensure the safe use of tower crane, the author thinks that the following points should be done:
1, the tower crane shall set settlement observation points immediately after the foundation construction is completed, and the observation points shall be located at four corners of the tower crane small platform (there is a small * * * point at four o'clock in each corner). Observation frequency should be at least three times a week, and settlement observation should be carried out in the whole process of tower crane use. With the progress of construction, the tower will be gradually improved, especially in rainy season, and accidents may occur due to foundation sinking and inclination. Therefore, it is necessary to observe the four corners of the foundation in time according to the specific situation and check the sinking and inclination of the foundation to ensure the safe operation and normal work of the tower crane. Understand the foundation settlement at any time, so as to predict the danger of foundation trench slope instability, tower crane tilt and so on.
2. According to the requirements of the construction site, strictly limit the slewing radius of the tower crane, lock the slewing limit, install an early warning device (early warning bell) within the slewing limit line, and start the early warning at a distance of 10 meter from the adjacent building, so that the tower crane driver can prepare for stopping the crane arm in advance to avoid the collision between the crane arm and the building.
3, take organizational measures, strict disclosure of tower crane command and driver, and supervised by specialized personnel. Commanders should strictly abide by the operating rules of "Ten No Lifting". Understand the weight of the hoisted object, grasp the center of gravity of the hoisted object, and bind the hoisted object according to the regulations, and the binding must be firm. In the case of a large span of the suspended object, it is necessary to ensure safety and reliability and put an end to the phenomenon of "falling flowers".
4. In order to ensure the safety of the tower crane, the tower crane shall ensure that the driver is on duty in the cab during working hours. Succession and successor personnel shall not leave the cab without face-to-face handover, and handover records shall be carefully made during handover. Tower crane and signal commander must be equipped with walkie-talkies, which must be locked after the frequency is determined uniformly. Users have no right to frequency modulation, and the special plane should be dedicated. The signal commander should be relatively fixed with the tower crane group, and the commander should not be changed at will without special reasons; Without the consent of the person in charge, the commander shall not change his post. In the process of command, strictly implement the response system between the signal commander and the tower crane driver, that is, when the signal commander gives the action instruction, first call the number of the tower crane being commanded, and then the signal commander can give the tower crane action instruction after the tower crane driver responds. The signal commander must always visually observe the crane hook and the hoisted object. The bell man must be serious and responsible, and shall not leave his post without authorization, with clear signal and correct command.
5, tower crane driver is strictly prohibited to drink and mount guard, to avoid fatigue operation; Turn on the machine at night. If you work overtime all night or for a long time, you must change shifts to avoid potential safety hazards caused by human factors.
6. In bad weather, in case of gale, rainstorm, heavy snow and fog with magnitude 6 or above, the hoisting operation should be stopped.
7, tower crane in the process of lifting the car back as far as possible, when the tower crane runs to the construction site, the heavy objects will be transported to the construction site.
8, the construction site should be set to meet the night construction of tower crane lighting lighthouse, the brightness will be subject to the crane driver can see the lifting rope.
9, bad weather, (level 6 (including level 6) above strong winds, heavy rain, heavy snow, fog), should stop lifting operations.
10. When the construction site suddenly loses power, the rotary braking of the tower crane will lose its function. When the tower crane rotates with the wind, the boom will touch the building. Based on this situation, a backup power supply can be added to the rotating brake coil. When the tower crane suddenly loses power, start the standby power supply, and the brake is still energized, so that no accident will occur. The backup power supply may be a battery pack. According to the working parameters of the rotating brake coil, the storage battery is installed in the control box of the tower crane. In order to prevent the battery pack from suddenly failing, the tower crane driver should check whether the battery pack has electricity at work every day (turn the rotary brake switch on the battery pack, and if the rotary brake is not engaged, it proves that the battery pack has no electricity). If there is no electricity, the tower crane driver should immediately charge the battery pack, so that the tower crane can operate normally. Its function is to supply power to the rotary motor in time when the tower crane suddenly loses power in use, so as to control the tower crane to brake in time and prevent collision with surrounding buildings.
1 1. When the work is over or after work, the boom of the tower crane may swing with the wind and hit the surrounding buildings, so a φ22mm concrete pier can be embedded within the coverage of the tower crane.
In addition to the above work, the construction should be carried out in strict accordance with the safe use procedures of tower cranes to ensure the safe use of tower cranes.
refer to
[1] Technical Specification for Safety in Use of Construction Machinery (JGJG33-2001)
[2] "Construction Safety Inspection Standard" JGJ59-99
[3] Technical Specification for Safety of Working at Height in Building Construction JGJ80-9 1
[4] Safety Regulations for Tower Cranes (GB5 144-2006)
[5] Technical Specification for Installation, Use, Dismantling and Safety of Tower Cranes in Building Construction (jgjgjg196-2010)
[6] Code for Construction Quality of Concrete Structure Engineering (GB50204-2002)
Brief introduction of the author
Yu Yanchun (1979. -) Male, from Hefei, Anhui, bachelor degree, engineer of Anhui Special Equipment Testing Institute.