Sunday, January 8, 2012

Subang Kelana Link Extension : The possibilities to by pass USJ Summit traffic light

Since there's numbers of comments on my previous posting on the Subang-Kelana Jaya link issue, I guess I need to elaborate further from my point of view why the idea of by passing  the USJ Summit traffic light would  create some other problem. 


As measured from Google Earth, the approximate flyover stretch at USJ Summit traffic light is around 120m. 


If AZRB need to built the Subang-Kelana Link by pass USJ-Summit traffic light , approximately another 600m of extension required to be built. The piling work for the piers can only be done up to extend as indicate below ,and of course some reconstruction work need to be done at this location as the existing flyover structure might be effected due to vibrations of piling works and other similar causes. 


As I mention before , the distance between the two piers is approximately 120m . The contractor can't built another pier in between as it would require them to re-construct the existing flyover. Therefore an option to built cable stayed bridge similar to LDP - Federal Highway shall be considered (as raised by commentators).

Below is a caption taken from Gamuda website , which indicating the the span between 2 piers of the cable stayed bridge for LDP - Federal Highway crossing is 85meter and I confirmed this with measurement from Google Earth.



The main different between LDP-Federal crossing and  'Subang Kelana Link - KESAS ' crossing is the elevating route . The tallest pier for Subang Kelana Link highway is 29m at Bulatan Kewajipan and the pier's height gradually decrease towards USJ Summit traffic light. If the Subang Kelana Link highway have to be landed bypass the USJ Summit traffic light numbers of piers need to be constructed up to as indicated on the earlier picture (no.3). The LDP-Federal crossing cable stayed bridge is not a continuous construction of an elevating route therefore less constraints to be considered during the design stage. 

Below is my sketch on both scenario ;



Route width for both crossings ;

LDP-Federal Crossing "Cable stayed bridge"

Subang-Kelana Jaya Link

Proposed "Cable stayed bridge" for Subang Kelana Link

By referring to the picture above, the bridge pylon construction can only be done at the indicated area, on the other hand the Subang-Kelana link 'extension' route (20m width) is in the middle of existing flyover (35m width). By right, the pylon should be construct alongside the proposed 'extension route' as per below picture .


It is no doubt this propose 'extension' for Subang-Kelana Link highway actually can be done, anyhow lot of  wise engineering decision and re-construction work need to be carried out. The continuous elevating route which extend to the cable stayed bridge also a concern in both engineering and aesthetically The structure of the existing flyover might be effected due to the re-construction and piling works. Other constrain is how the limited spaces need to be utilized ? I believe in the beauty of science and engineering , it's just that sometime I'm quite skeptical on certain ideas which did not considered seen and unseen constraints.

1 comments:

Tahniah

Fakta yang jelas dan saya terima penerangan anda yang terang dan jelas dengan hati terbuka.

Betul jambatan itu boleh bina namum dalam masa yang sama kos tambahan untuk jarak yang sikit itu saja boleh menjadi ratusan juta.

Good Job..

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