3D modular buildings in Israel – understanding gaps and developing local prototypes
According to the Israeli central Bureau of Statistics (CBS), Israel is expected to reach a population of 15 million by the year 2048. Residential needs are expected to grow rapidly, and reach ~67,000 dwelling units per year in 2036-2040. With existing technologies in Israel, the average construction time is ~26 months per dwelling, and the total construction sector’s capacity amounts to no more than 50,000 dwelling units per year. On top of these, there is almost no local source for construction site workers, and the demand for foreign manpower is growing constantly.
To slow down the growing gap between demand and construction capacity, it is essential to increase the performance and efficiency of the construction sector. Industrialization in general is one of the proven means for improving productivity. Modular Construction, the construction technology for high-rise buildings that is based on prefabricated 3D units prefinished in the factory, comprises one of the highest levels of industrialization. This technology is also known as PPVC (Prefabricate Prefinished Volumetric Construction) in Asia and Australia. Experience gained abroad shows that it may become a lever to increasing the construction sector’s capacity, in particular for various sorts of residential buildings (including dormitories, apartments for rent, buildings for the elderly, etc.) as well as for some other building types (educational, hostels, hotels, medical, etc.).
In the last decades, experience with implementing Modular Construction in high-rise and tall buildings was gained worldwide (USA, Great Britain, Latvia, Poland, Finland, Sweden, Denmark, Russia, China, Singapore, Japan, Australia, etc.). Lately a residential building of 32 floors has been constructed in Brooklyn NY, and a 40 story building project is under construction in Singapore.
The framework of this research project included the first study of Modular Construction in Israel. It was devoted to an extensive literature survey, collecting as much as possible, exhaustive information and data on the technology’s details, know-how, experience in implementation, as well as to examining the feasibility of implementing this technology in the construction of high-rise and tall residential buildings in Israel.
The main activity in Modular Construction takes place in the factory, where large 3D units are produced, usually along a production line (similar to the production of cars and buses). At the end of the line emerges a completely finished 3D room high unit that is ~3.4 m wide and 10 to 16 m long. The unit’s structural system would be a main component of the building’s final structure. The unit’s walls, partitions, ceiling and floor include all the required acoustic and thermal insulation layers. It also includes all the cables, pipes, electrical and sanitary fixtures, flooring and any other fixed items that are relevant to the functional rooms comprised within the unit.
Performing all works in the factory at normal working height and good accessibility to every item, with comfortable working conditions, excellent safety conditions and a socially solid working environment, workers’ output is improved and quality of the units in general, as well as of specific building details, is much better than in conventional construction on site. The well planned works in the factory also enable recycling of materials and much less construction wastes. The major reduction of total manpower hours on site reduces safety risks and increases total safety on site. It should be recognized, however, that working with high capacity cranes and transporting and assembling heavy units comprise an increased safety risk that must be handled appropriately. Although transporting 6 to 10 units per day to the construction site, the total transportation load around the construction site is reduced due to less manpower on site and almost no need for transporting individual components and materials. As works on site are mostly dry, there is hardly any disturbance to the nearby neighborhood.
Modular Construction requires that planning and design are completed before manufacturing of a unit starts in the factory. There is hardly any tolerance for design changes later on. This requires a conceptual change of the design and construction process. It is thus expected that at the beginning of implementing the technology in Israel, some failures may occur that would stem from the old way of project management, but after a learning period all stakeholders will recognize the advantages of the new process and will become adjusted to it. Nevertheless, due to the completion of detailed planning and design at an early stage, it is also possible to plan and design quite accurately the schedule, costs and cash flow along the entire project’s process, and these materialize without major discrepancies. Consequently, credibility increases between all stakeholders, and the Modular Construction project ends with very few disputes and litigations.
Accumulated experience abroad proved that the following technological advantages can be fully realized: reduction of total project duration by 35% to 65%; good control of construction details, with reduction of faults and improved final quality; reduction of site manpower by 50% to 75%, and 3 to 4 times increased productivity; increase safety on site by 3 to 4 times along the whole project; reduction of wastes by 90%, of site deliveries by 60%, and of workers and materials transportation by 70%; major reduction of noise and dust impacts on the nearby neighborhood; and major improvement of the working conditions of all workers associated with a given project.
The research included a survey of Israeli professionals’ perceptions of Modular Construction. It showed, as in similar investigations abroad, that the professional sector recognizes the technological listed above merits of the technology, but points also at some disadvantages, which stem mainly from lack of familiarity with handling the technology’s subtleties.
We found that implementing Modular Construction technology for high-rise buildings in Israel has the potential to advance the construction sector, to improve its image, and to raise its status to that of the manufacturing industries, such as of cars, buses, airplanes, and ships.
Despite this observation and the mentioned advantages, the technology’s innovative nature, the lack of local experience with its application in high-rise buildings, and the connotation as PreFab stop potential entrepreneurs from “diving into an adventure”.
any actual drawbacks that occur along the project.
Funding:
The research was funded by the Israeli Ministry of Construction and Housing. Grant 20-17. 2017
The project team included:
Assoc. Prof. R. Becker; Assoc. Prof. Y.J. Grobman; Dr. G. Raviv; Assoc. Prof. Y. Rosenfeld; Arch. N. Chen; Dr. I. Leviathan; A. Maayan, M.Sc.;M. Tavor, M.Sc.; G. Trajtenberg, M.Sc.
Scientific reports that were published on this research:
Becker, R., Grobman, Y. J, Rozenfeld, Y., Raviv, G., Chen, N., Leviathan, I., Maayan, A., Tavor, M., Trajtenberg, G., Residential buildings industrialization using 3D modular units – Architectural, engineering and construction aspects. Final report for grant # 2025217. Israeli Ministry of Construction and Housing. 9. 2019 (In Hebrew with an English abstract at the end).