To expedite the process and make it more cost effective, Delhi Metro Rail Corporation (DMRC) is making use of gigantic 25 metre-long girders to join spans on elevated stretch of the section.
‘‘The cost of construction with the existing 3-meter spans works out to Rs 24 crore per km, while the 25-meter ones cost Rs 19 crore per km. So using the bigger spans will result in a saving of nearly Rs 5 crore per km,’’ said a DMRC official.
It looks like this..
The bigger spans work out to be more economical and also speed up pace of the construction. Officials said it takes about a week to join the space between two pillars using segmental construction while the bigger spans can be put in place in just one day.
The only problem associated with this is the space needed to transport and hoist these segments..this could be a bottleneck for BMRCL.
However dont we have such roads where this is possible? NH4 and Mysore road? Shouldnt we be doing this and saving costs??
Comments
Fenders for via-duct columns
In many stretches of Metro Rail junction like Swami Vivekananada Road (Ulsoor) and MG Road, one can see that there are no fenders around the columns of Metro Rail via-ducts. Only the bases of these columns are enlarged. There does not seem to be any plan to build a median along the line of the columns.
A basic question - what if a vehicle on the road hits a column? Are the columns designed to take the impact? Or, don't we expect any mishaps? I do not think the probability of a vehicle impact is very low. Just look around the number of broken or bent light poles in the medians of Bangalore roads. Most of them are in that state because of vehicle hits. And in spite of being embedded in the safety of the median kerbs.
median plan..
BMRCL has mentioned about median plans all along the route..they want to have plants here etc..a sample median is done up infront of webbs/raheja towers on MG road..
So we should have some safety..
monorails
Monorails have such spans. Actually it has 2 beams bwtween pillars, so beam being much narrow, it is easy to transport..
commons.wikimedia.org/wiki/File:Kl_monorail.jpg
Even metro ppl using 2 spans between pillars it seems. That is 2 narrow spans parellelly like monorails. So it is half as narrow, so transport of spans is easier unlike mentioned above in blog.
I think this needs columns to be closer.