Increased population and rapid urbanization have resulted in a scarcity of housing space in the cities across the country. With land space at a premium, there has been an increasing demand for high-rise buildings, on smaller urban sites, which need to be built quickly and to tight budgets.
Tower cranes play a crucial role on such construction sites; both for logistics and construction, and their productivity can make or break a project's timeline. They are now essential for constructing high-rise buildings because it provides economical solution of lifting heavy loads.
The key design elements of tower cranes have remained largely unchanged for many decades. With proper maintenance and repair, they can have a long lifespan – so cranes have not typically been at the forefront of innovation in the construction industry.
In recent years, however, changes in the construction sector and increasing improvements in health and safety have driven innovation in tower crane technology. This has resulted in higher levels of safety as well as better productivity and the ability to work in more challenging environments.
Today's tower cranes are equipped with advanced technology, provide ease of lifting heavy construction materials to large heights, and require minimum time and effort. These advanced tower cranes make use of camera systems, wireless video control, and radio frequency identification (RFID) technology for efficient communication, and sensors, better anti-collision systems, and safety devices for safe crane operations.
Tower cranes are safety-critical: a tower crane's height means any accident, especially collisions with other cranes or buildings, can result in serious injuries or death, whether for the crane operators, the workers below, or even members of the public. Beyond the loss of lives and lost work time, tower crane accidents also bring negative publicity to a worksite, affecting the reputation of the contractors and even their client, the developer.
Tower cranes are normally positioned with overlapping workspaces and special care has to be taken in “no-go zones” areas where potential collisions can occur. Normally, only a single crane can operate in this zone, coordinated by a “banksman” on the ground, but cranes can be operated more freely when an anti-collision technology system is in place. Crane operators feel more relaxed and experience less stress when working with the system, meaning they can work more efficiently over a long shift.
A tower crane anti-collision system is an operator support system for tower cranes on construction sites. It helps an operator to anticipate the risk of contact between the moving parts of a tower crane and other tower cranes and structures. In the event that a collision becomes imminent, the system can send a command to the crane's control system, ordering it to slow down or stop. An anti-collision system can describe an isolated system installed on an individual tower crane. It can also describe a site-wide coordinated system, installed on many tower cranes in close proximity.
For tower cranes, the anti-collision technology system relies on precise sensor data, including the placement of the crane jib, its height, and the load on, and position of, the lifting hook. Wind speed and direction are also measured – if the wind is coming in at a right angle to the boom the crane will need to increase its braking distance.
Another innovation that is being used more frequently on sites is crane hook camera technology to avoid blind spots for the operator and to provide a better view of the load from the operator's cab. The camera system provides the crane operator the ability to communicate to the banksmen (riggers), slingers, and signalers with any information necessary to move from point to point in a more controlled environment, and enhances the ability to communicate more efficiently.
Camera systems give a close-up view of the load below the hook and surrounding area, which gives the crane operator more situational awareness, allowing an increase in speed and accuracy in all scenarios. This improves the lift efficiency and reduces time in task completion.
Camera systems are a visual aid and help position the hook block into the required position whilst working in tandem with the instructions given by the banksmen/slinger over the radio, complimenting and confirming the correct position, keeping a steady flow of continued and sustainable lifting tasks, helping to increase productivity.
As modern construction sites are becoming more and more congested and as buildings are going higher, crane operators are required to place their loads in even more restricted and tighter areas than before. The probability of impacts and collisions is still as great if not more so. Having a camera fitted with its clear and uninterrupted audio-visual feed allows the operator to respond to any adjustments to avoid any potential accidents before they happen, allowing for a safer and more productive lift.
Tower crane cameras solve the problem of blind spots, poor visibility in bad lighting or weather conditions, and minimize injury potential to the crane operator. Having a camera on a crane also can enhance productivity by cutting down on time spent trying to view poorly lit or dangerous areas. Having eyes on any and all parts of the Jobsite proves extremely valuable when working in construction.
The safety devices installed on the tower crane include a weight limiter, a lifting torque limiter, an amplitude limiter, a lifting height limiter, a swing limiter and etc. The function of these safety devices is mainly that once the tower crane exceeds the safety value in the process of use, the power supply will be automatically cut off to avoid tower crane accidents.