Bangkok is expanding its local transportation network: the completely new Red Line is designed as an elevated railroad. The name is derived from the color code of the local transportation system in Bangkok. The new Red Line is part of the government’s master plan aiming to increase local public transportation capacities in the metropolitan area. It stretches from the new main station “Bang Sue Grand Station” presently under construction to Rangsit in the north and Taling Chan in the west.
The northern line section, the Dark Red Line, has nine stations, a length of 21.6 km and is completely designed as an elevated railroad. In each direction of traffic, there are separate 22 m high viaducts with two tracks each. In total, in each direction of traffic, 589 single-span beams follow one another featuring an average span width of 36 m. The opening of the complete Red Line is scheduled for January 2021.
New technology for the new railroad line
In Thailand, traditionally elastomeric or pot bearings are used for railroad bridges. The former have the disadvantage of deflection by traffic loads, the latter feature low durability and only allow for limited function control.
“We were able to convince the building owner SRT (State Railway of Thailand) that spherical bearings with MSM and MSA technology are the appropriate solution for the new railroad line,” explains Georg M. Wolff, CEO of Civil Engineering Solutions (Thailand). “These bearings enable maintenance-free and low-wear load accommodation and movement.”
In Thailand, durable and maintenance-free bearings of this quality are used for the first time. The MSM® sliding material accommodates and transmits high loads, also in combination with highly accumulated sliding paths and temperatures. The calottes are made from MSA®, a sliding alloy that does not corrode even in tropical climate or in a marine environment. Together, MSM® and MSA® ensure an outstandingly long service life of the bridge bearings.
Each single-span beam rests on four bearings: one free-sliding bearing, one transversely sliding bearing, one longitudinally sliding guide bearing and one fixed bearing. They accommodate structural loads between 3,579 and 8,715 kN (ULS) and feature a diameter of up to 700 mm. They transfer the weight of the load-bearing structure and the traffic loads restraint-free into the pillars and allow for climate-induced length variation of the viaducts.
4,712 spherical bearings
The challenge was to deliver the large quantity of 4,712 high-quality spherical bearings at a reasonable price and in due time. The bearings were manufactured at MAURER INDIA in Bhopal in 2015/16. The MSA® calottes and MSM® sliding plates were delivered from Munich. The installation was carried out by the customer Italian-Thai Development PCL, the largest building contractor in Thailand.