Rising Technologies: A contribution to the Miami High-Rise Expo
As a part of the Miami High-Rise Expo hosted by the University of Miami School of Architecture, we will talk in-depth about the new technologies of Rising Formwork and cranes, condensed into the theme known as ‘Rising Technologies’. We correlate these rising technologies to the concept of ‘self-rising’ or ‘self-climbing’, a feature that essentially eases any construction process. This will involve the in-depth look of each of the technologies, including the definition, how it works, the pros and cons, and workers’ personal experience with using the technology.
What is Rising Formwork? Rising formwork (also known as climbing formwork) is a special type of formwork that rises with the buildings’ rising progress. It is especially used for tower buildings that have a repetitive structure. The focus of Rising formwork, in this case of innovative technologies, would be self-rising, or self-climbing formwork. This type of formwork elevates itself with not the help of cranage, but with mechanical leverage, such as hydraulic pistons supplemented by compressed air. The kind of elevation explained is usually fixed to railings emplaced against past concrete pours, allowing for smooth escalations of about 0.2 metres per minute (categorized as sliding formwork). MahanaKhon, for example, utilizes the sliding formwork to ensure, simultaneously, construction progress and the safety of site workers. Despite needing specific formwork plans for each level due to the tower’s complex structure, the formwork allowed site workers to work two levels below, in optimal conditions of safety, as the formwork continued to rise.
But with the Banco de La Nacion, for example, utilized brackets and cones that attached to the lower levels of the walls for support. Another method known as gliding formwork allows for seamless creation of structures, opposed to stopping in intervals with the remote-controlled hydraulics method. This kind of rising formwork avoids disassembling the formwork as well as hoisting any cranes for the formwork, freeing up space in addition to adapting to any weather conditions. The rising formwork used for the Banco de La Nacion was the SCP400 self-climbing formwork, the most advanced construction technology in the world (at the time of construction, according to COSAPI). The innovative system led to a reduction from 10 to 5 days within the construction development for each floor.
Of course, no technology is perfect. What can be seen as a flaw for rising formwork is its slightly complicated set-up and hefty costs (depending on ones’ construction budget). For example, the deshuttering process of the Banco de la Nacion required 2 phases: the first was to remove the internal core by means of a ‘sliding hanging system operated using rails’. The second phase following after was the external deshuttering. The job overall required the highest qualified personnel who worked in rotating shifts 24 hours per day while meeting high safety standards. This was the maximum result to produce little to no margins of error.
Despite those flaws, the innovations of rising formwork have helped greatly in creating wonderful architecture like the Banco de la Nacion and MahanaKhon, in addition to reducing construction durations and manpower.
What is Rising Crane? So, you may have, at least one point in your life, come across a construction crane perched atop a tower and wondered, “How’d that get up there?” Then, you may have had that one friend that has all the knowledge at the palm of his/her hand and told you about it as if it was something you could read off a Wikipedia article. Whether there was no friend or that friend was right/wrong, let’s discuss just what is the innovation of rising crane (also known as climbing crane) technology.
To start, all cranes have their basic parts. A base that is attached to a large concrete pad (or foundation) to support the crane. A connection to the mast that gives the crane its’ height, followed by the slewing unit, working arm, and operator’s cab. Typically, a tower crane has to be attached every 10 levels to the building, where the maximum could reach up to 70 meters horizontally. It has a maximum lifting power of 18 metric tons, however the most common ranges up to 5 tons at the end of the boom, and counterweights whatever quantity, depending on the crane capacity.
The method focused on for the expo is the ‘internal’ method of rising cranes. This method consists of the crane being inside the building, building a few floors at a time, and then jumping the crane to a higher spot. This is the method that applies to the resources used in the Banco de la Nacion: a self-climbing crane that frees up finished floors where work has been finished. The external method consists of the crane being outside of the building –with a few steel arms attached- expands upward alongside the building. There is also a 3rd method, though not used as often, that consists of a helicopter carrying the crane to the top of the tower.
All methods have their pros and cons, all based on the construction scenario. The internal method is great in that it frees up space around the building site and accelerates construction, but work needs to be done on the lower level first for the installation of the systems. The system also needs to be taken in consideration during the design stages, and disassembling takes more time after construction is complete. There are also scenarios in which after freeing up the floors to resume construction on the next ones, they are still unfinished. This means that workers would have to head back to each floor, and finish them up. However, there is the case with the Banco de la Nacion, where the self-rising crane that was used would climb through the elevator shaft, allowing floors to be finished as it continued to climb. In vice versa, disassembling is easy for the external method, but it takes up a good amount of space in small, tight areas.
(defining rising formwork, includes some cons of formwork as well)
(sliding formwork defined, formwork elaborated)
(sliding formwork, safety)
(complex structure, specific formwork plans)
(definition for rising cranes, also mentions the con of having to disassemble cranes if internal)
(Banco de la Nacion on rising formwork and rising crane)
(explaining the cons of NOT using formwork)