A First in Israel: Technology Expected to Cut Tower Construction Time by a Factor of Three
By Jacki Wiluzanski · · Updated · 3 min read
A new construction technology being implemented for the first time in the Withania towers in Tel Aviv, next to La Guardia, is expected to shorten construction threefold, according to the company Withania, which is using the technology for the first time in office towers.
This is a unique technology developed by the Austrian company GBG GLEITBAU SALZBURG, which rents the equipment to the company. The technology makes it possible to raise the tower core using a "sliding formwork" system, which operates with the help of hydraulic pistons and lifts the system up over the surface of the hardened concrete. The technology will also be applied in the TOHA 2 offices on the Yigal Alon axis in Tel Aviv, a Gav-Yam project.
By using the "sliding form" system, it is possible to advance the construction of the walls of the tower core, the shafts of the elevator rooms and stairwells, which provide the rigidity of the entire structure, which is about 180 meters high, at a construction pace of 1.5-2 meters per day. This compares with standard construction, where construction progresses at a pace of about 10 to 15 meters per month. Thus, instead of building the tower core in about 12 months, the company will be able to finish its construction in only about 4 months.
"It is a difficult process, a truck pouring concrete is needed on site all the time"
"The use of this technology in Israel has already been carried out in the past in the construction of the control tower in Israel and in the chimneys in Hadera, but building an office tower is much more complex," says Ilan Shoba, project director of the "Withania Tel Aviv" project, where construction is done using sliding formwork.
"In the construction of an office tower, and certainly in a tower with a combination of uses as in our project (commercial, office and residential), the technical shape of the core is different. It is not a large shaft without partitions, but a very large core with partitions, elevator shafts, large and small openings for system passages and door openings that require reinforcement through additional earthquake-resistant reinforcing elements.
The idea behind the method is to raise the formwork system with the help of hydraulic lifts that rest on the hardened concrete. This creates a cycle of hardening the concrete layer to a level sufficient for the system to be raised hydraulically to pour a new layer of concrete. The pace of progress depends, of course, on the type of concrete and the pace of preparing the rebar to continue the pour, but, as mentioned, it averages about 1.5-2 meters per working day in terms of output.
In the end, at this pace, it is a system that raises an office tower in a quarter of the time it would take to raise it to a given height with common construction technology. Shoba explains why other companies have not yet used this technology: "It is a difficult process. With this method, a concrete truck pours all the time on site, and every day we need rebar for the floor." He concludes by saying that although the costs of the system are higher, this is offset by the construction time.
