In this blog post, we will examine the structure and operating principles of the ACS FORM (Auto Climbing System) method, its construction efficiency, and real-world application examples.
Concrete is the most widely used material in modern architecture, serving as the structural framework for buildings through elements such as columns, walls, and slabs. Columns, walls, and slabs are constructed by mixing cement, aggregates, water, and admixtures to create a concrete mixture, pouring it into formwork, allowing it to cure completely, and then removing the formwork. Conventional concrete column construction involves pouring concrete into formwork that is 2 to 3 stories high, removing the formwork after curing is complete, and then using a crane to lift and reinstall it for the next process—a cycle that is repeated. Since production costs rise sharply and crane lifting becomes difficult once the formwork exceeds a certain height, this method involves building up in stages to a specific height.
The ACS FORM method is one such conventional concrete structure construction method; “FORM” refers to the formwork, and “ACS” stands for Auto Climbing System. Literally interpreted, it is a method that applies an automatic climbing system to the formwork; the key feature is that, instead of lifting the formwork with a crane as in the past, the formwork is designed to ascend on its own.
On actual construction sites, the components of the ACS FORM system—such as work platforms, hydraulic cylinders, gears, and formwork—are attached to a layer of hardened concrete at a specific height, and concrete is then poured from above. Although concrete is poured in layers of the same height as in conventional methods, the key difference is that the formwork automatically ascends by climbing up the hardened concrete using hydraulic cylinders as its power source.
The system consists of a device that secures the entire system to the hardened concrete, a hydraulic lifting mechanism that automatically raises the formwork, and a work platform for workers. The formwork consists of thin rectangular panels that shape the concrete, while other structural components attached to the concrete surface support the formwork and facilitate its ascent.
The ACS FORM method plays a crucial role in shortening the construction period of reinforced concrete structures. Reinforced concrete structures have the disadvantage of being more difficult to manage on-site and having slower construction speeds compared to steel structures; in particular, the slow construction speed directly affects the contractor’s profitability. ACS FORM resolves these issues to a significant extent.
When applied to vertical structures, the automatic formwork hoisting device eliminates the need for equipment such as cranes, greatly reducing the time required for formwork installation and removal. Furthermore, since ACS FORM is equipped with built-in work platforms, work efficiency improves, resulting in faster construction speeds.
Constructing vertical and horizontal structures separately is advantageous in terms of construction speed. This is because proceeding with vertical structures (columns, walls, etc.) and horizontal structures (slabs, etc.) simultaneously entangles tasks of different natures, complicating the construction process. In particular, for super-tall buildings exceeding 100 stories, there is a strong tendency to construct vertical and horizontal structures separately, and vertical structures are typically constructed before horizontal ones. In such cases, ACS FORM is primarily applied to the construction of vertical structures.
A notable example of ACS FORM’s application is the Lotte World Tower (123 stories, completed in 2016) in Songpa-gu, Seoul. The building’s primary vertical structures include eight thick Mega Columns and a single Core Wall concentrated at the center of the building; the ACS FORM method was applied to the construction of these vertical structures.
Site photos and drawings show that the eight Mega Columns and the Core Wall are arranged in the lower structure from the first basement level to the 10th floor above ground, and it can be seen that the steel structures attached to the side of the Core Wall are very similar in form to the ACS FORM configuration. This application demonstrates that ACS FORM makes a substantial contribution to shortening construction schedules and improving work efficiency in the construction of large vertical structures.
