Sosrobahu is a road construction technique which allows long stretches of flyovers to be constructed above existing main roads with a minimum of disruption to the traffic. The technique was designed by Tjokorda Raka Sukawati and involves the construction of the horizontal supports for the highway beside the existing road, which is then lifted and turned 90 degrees angle before being placed on the top of the vertical supports to form the flyover pylons. This technique is of considerable value in increasing road mileage in large cities where there is a restricted space for new roads and where the closure of existing roads for the length of time to build a flyover using normal construction techniques would impose significant economic costs.
In November 1989, President Soeharto of Indonesia gave the name Sosrobahu to the new technology. The name was taken from a character in the Mahabharata, and derives from Old Javanese for thousand (sosro) shoulders (bahu).
Tjokorda's invention was used by US engineers in the construction of a bridge in Seattle. They placed the oil under a pressure of 78 kg/cm² (7.6 MPa) as per Tjokorda's original theories. Tjokorda himself wanted to investigate further the limits of his invention and built himself a laboratory where he successfully tested the LPBH to a limit of 78.05 kgf/cm² (7.654 MPa).
Patents have been granted for the invention from Indonesia, Japan, Malaysia, and the Philippines, and has been applied for in South Korea. The Indonesian patent was granted in 1995, while the Japanese patient was granted in 1992. The technology has been exported to the Philippines, Malaysia, Thailand and Singapore. The longest stretch of overpass built using this technique is in Metro Manila, Philippines at the Villamor/Bicutan link located at the southern part of the metropolis. In the Philippines, 298 supports have been erected, while in Kuala Lumpur, the figure is 135. When the technology was introduced to the Philippines, the President of the Philippines, Fidel Ramos commented: "This is an Indonesian invention, but is also an ASEAN invention".
A second version of the technology has been developed. Whereas the first version used a steel anchor inserted in a concrete base, the second version uses a single plate with a hole in the middle which is not only simpler, but also significantly speeds up the time it takes to erect a pylon from 2 days to 45 minutes. It is expected that the lifespan of flyovers constructed using the Sosrobahu method will be approximately 100 years.
According to Dr. Drajat Hoedajanto, an expert from the Bandung Institute of Technology, Sosrobahu is a very simple solution to the problem of erecting flyover pylons and is suitable for use in the construction of elevated toll roads which have traffic running underneath them. Sosrobahu is clearly a useful and versatile technology.
Sosrobahu - Wikipedia, the free encyclopedia