Spierings SK599-AT5

The Spierings SK599-AT5 was developed to fill the gap between the medium four-axle machines and the heavier six-axle class, targeting projects that require higher load moments and reach without the added complexity of very large transport configurations. Built by Spierings, the SK599-AT5 reflects Spierings’ core philosophy of delivering true tower crane performance on a road-going chassis, optimized for urban and semi-urban environments.

Mounted on a five-axle carrier, the SK599-AT5 offers a favorable compromise between mobility and stability. The additional axle compared to AT4 models allows higher permissible transport and operating weights while keeping overall dimensions manageable. Multiple steerable axles provide good maneuverability, enabling the crane to access congested city streets and confined construction sites. Road travel speeds are typically up to around 80 km/h, supporting efficient relocation between projects.

The crane superstructure features a lattice jib with a working radius typically in the range of approximately 50 to 55 metres, depending on configuration. At short radii, the SK599-AT5 delivers a maximum lifting capacity of around 8 to 9 tonnes, while at maximum outreach it offers practical capacities suitable for handling formwork systems, prefabricated concrete elements, and structural steel components. By raising the jib to steep angles, the crane achieves increased hook heights, making it effective for mid- to high-rise residential and commercial buildings where vertical reach is critical.

A key advantage of the SK599-AT5 is its fully automatic, one-man erection system. Erection is carried out at the push of a button, following a controlled and compact assembly curve that minimizes the space required around the crane. This allows setup close to existing structures and in restricted areas where conventional tower crane assembly would be difficult. Once erected, the crane can remain standing between work phases without dismantling, improving overall site efficiency.

All crane working motions—including hoisting, slewing, trolley travel, and erection—are electrically driven. Electrical power is supplied either by an onboard diesel generator or via an external site power connection. When connected to external power, the SK599-AT5 operates quietly and with zero local emissions, an important benefit for city-center projects and sites with strict environmental or noise regulations. The electric drives provide smooth, stepless control, allowing precise load positioning comparable to that of a traditional top-slewing tower crane.

The crane is supported by a four-point hydraulic outrigger system with automatic leveling and electronic inclination monitoring. Different outrigger base widths can be selected to adapt to site constraints, balancing available space with required lifting performance. The stable five-axle carrier and balanced superstructure provide predictable handling and consistent performance across the working range.

The operator’s cab is designed to tower crane standards, offering good visibility, ergonomic controls, and a comfortable working environment for extended shifts. Integrated monitoring and safety systems continuously provide feedback on crane configuration, load conditions, and wind limits, supporting safe and efficient operation.

Overall, the Spierings SK599-AT5 stands out as a versatile and capable mobile tower crane that bridges the gap between compact urban machines and heavy-duty large-axle cranes. Its combination of five-axle mobility, fast self-erection, electrically driven crane motions, and strong lifting performance makes it well suited for demanding urban construction projects where flexibility, reach, and efficiency are key requirements.