If the August 2017 Environmental Impact Assessment (EIA) of Bangalore Metro’s upcoming 21.415 km Line-4 (Gottigere – Nagawara) is to be believed, then the Bangalore Metro Rail Corporation Ltd. will have its civil contractor utilize U-shaped girders for building the viaduct of the line’s 7.501 km elevated section between Gottigere – Swagath Road Cross. This will be the first time U girders have been used in the city, as up until now the BMRCL’s design team had its contractors utilize prefabricated segment boxes which are later post-tensioned to form a span between adjacent piers.
AECOM is the line’s detailed design consultant (DDC) and Simplex Infrastructures recently emerged as the lowest bidder for constructing the elevated portion which comprises of 5 new stations at Gottigere, Hulimavu, IIM-Bangalore, JP Nagar 4th Phase and Swagath Road Cross (see Phase 2 map).
Relevant excerpt and diagram from the EIA document –
These girders are typically 24.90m – 27m long and have previously been utilized to build portions Lucknow Metro’s Line-1, Kochi Metro’s Line-1, Mumbai Metro’s Line-1 and Delhi Metro’s Violet & Airport Express lines. Although they require a lot more space to get launched, and as such often done only at night, they do help to build lines more rapidly and provide a smoother, aesthetically pleasing and unified look to the structure. That’s why operators continue to choose them for building new lines in the cities of Delhi (Red Line), Mumbai (Line-2, Line-7) and Noida (Aqua Line).
The EIA document was prepared to meet the loan requirements of the European Investment Bank (EIB), but all of the information in it might not be accurate to date. It reconfirms that the line will be equipped with a 25kV AC overhead equipment (OHE) system, but the BMRCL’s CPRO continues to insist that 3rd Rail will be utilized. It also claims the underground Cantonment Station will be “integrated with the Bangalore Cantonment Railway Station” and come up in the “front side car parking area” (see page 20) which is clearly not the case as seen in the line’s detailed alignment released in July.
For more updates, check out the Bangalore section of The Metro Rail Guy!