Crane Installation – Why are crane jibs left vertical when not in use?
Introduction to Crane Installation:
The crane jibs are not always vertical and, in many cases, would be in a dangerous position if left vertical. When they are left vertical, it is usually for more practical reasons. Do not assume that there is less force on the crane structure when the boom and Jib are almost vertical. Yes, the arm and the spear may see less force, but they are incredibly strong and designed to withstand forces far greater than their own dead weight.
What usually concerns us is the inversion of forces. In many configurations, the highest tipping forces occur when the Boom and Jib are at high angles with no load on the hook. This is because the counterweight designed to counterbalance a heavy load within a given radius creates an unbalanced condition as far as the crane installation is concerned.
Hydraulic mobile crane installation:
In the case of a mobile hydraulic crane, the Jib can be stored in an almost vertical position in an urban area to save space. Lowering the Jib at a certain displacement, or even to the ground, can consume a lot of space needed for other deliveries or pumping operations. Folding and removing the clamp takes time, and leaving it assembled can save an hour or more every day.
The Jib can be stored in an almost vertical position for a similar reason; real estate. The upper part of the crane is left free to rotate with the wind. Since the tower crane is presumably located in a dense urban area, you will not want your arm to rotate on your neighbors' building or another tower crane in the same location.
In the operation manual of any crane, there is usually a section devoted to acceptable storage locations for various configurations and different climatic conditions. The manufacturer will specify items such as the appropriate arm and arm angles and when the top can be locked or allowed to turn or "twist."
Most commonly, in the crane installation, you will see mobile hydraulic cranes parked with a swing or folding arm stored at zero degrees to the main Jib. While this may be what we see most often, manufacturing more than likely allows for multiple angles of displacement, usually 0, 20, and 40 degrees. The parking configuration table in the manual will provide the appropriate jib angle for this shift and specify the maximum wind speed for this configuration. This is something we should know before crane installation.
Crawler cranes and mobile cranes with lattice jibs and wishbones can be stowed in a variety of positions, although they are not always vertical. You can see these large cranes with a nearly vertical 88-degree main jib with a jib offset of only 10–20 degrees when parked. A more conservative parking position is the "pocket knife" position, where the main arm is at a high angle, and the tip of the Jib is close to the ground. Technomax Provides services for crane installation in Abu Dhabi.
You can imagine similar reasons when considering how to store one of these large cranes. Much easier to get it to work on your website than to put it on the street every day. This will saves not only time and space, but also a skilled operator is required to get in and out of horizontal and knife positions.
Light on safety after crane installation:
A highly skilled operator is required to move large cranes in and out of approved storage locations. Many accidents occur when the crane is moved from an operational position to a storage position and vice versa.
• Evacuate the area located in the path of the boom and Jib as you move the crane to and from a parking position that is at least equal to the total length of the Jib and Jib.
• Be sure to always follow the manufacturer's approved procedures. Do not substitute the crane's software or safety features.
Check the local weather forecast regularly to check the surface speed and gusts for the length of time the crane will be stationary. I recommend the National Weather Service's local weather maps for you in the UAE.
• Assign a person to monitor weather conditions during long parking periods and ask an operator to move the crane to an appropriate location if the expected weather conditions change. If possible, place the crane in the most conservative parking position if the crane is left unattended for more than a few hours. This usually means a horizontal jib with the tip of the Jib on the ground.
• If using a hydraulic arm and a swing arm, consider fully retracting the Jib and placing it in a horizontal position. If a hydraulic failure occurs while the crane is not supervised, the Jib and Jib may fall, or the crane may become unstable.
• If using a parking position that is not listed in the operator's manual, consult the manufacturer's technical department for customs procedure and wind speed criteria.
When the Jib of a Luffing crane is somehow parallel to the ground, the weight of the Jib transmits a tipping moment on the crane. When the Jib is more vertical, the load becomes axial so that there is less stress on the entire system if left unattended when not in use. Also, the rotational force applied to the base of the crane is less if the wind blows. Tower cranes are usually left free to turn like a weather vane in the event of a wind storm. Technomax has earned a leading name in providing services for crane installation in Abu Dhabi