Post tensioning works are finding it’s greater importance in overcoming the difficulties in progressing the construction works in the traffic areas.
PT works are predominantly used in the Metro rail constructions in all the cities that are currently in progress and some cities it is extended in phases.
Brief methods of metro rail constructions
– Over head via duct
– Under ground tunnel
PT will not be required for the underground tunnel.
The overhead construction of Rail track are done by precast segments and those segments are assembled and brought to the actual site and then using suitable erecting Gantry the segments are erected in between the pier with the applications of the post tensioning.
PT work in Precast yard
Match cast take place and here the ducts are placed as per the required locations and segments are produced either in a long line or short line methods.
Here the PT Engineer and PT firms scope has to properly instal the ducts both on the Web and as well as on the deck as per the drawings.
PT strands installation and stressing
Once the segments are lifted up by the Gantry in between the piers they are arranged in such a way to full spans and then erected after threading the PT high tensile strands and stressing is completed as required for the spans. Once stressing successfully competed the Gantry will move to the next span for the erections of the Precast segments .
The procedures are repeated and the method is called as span by span erections.
Stressing records and stressing pressure
Once the stressing is over the elongation computation shall take place and the stressing activity and it’s completion shall be validated based on the site elongation measured.
Each spans the stressing record and the stressing pressure are more important for the performance of the Girders as one monolithic element.
The Grouting has to be carried upon the successful. Completion of the stressing to fill the space between the ducts and strands and it is done through the application of pressure to fill the voids.
The above are the process of Carrying out PT works in the segmental construction and this method used mostly in metro constructions.
Utracon has been evaluated by the Chennai metro rail Corporation and approved to carry out the PT works for the construction of via duct from the Airport segment to OTA, St. Thomas mount, Alandhur Station and at vadaplani.
Utracon coordinated with the CMRL authorities and worked with the main contractor URC and NCC and successfully completed the assigned PT works. Courtesy CMRL, URC and NCC for opportunity given to utracon.
PT works and its importance in the India Railways:
Indian Railway is one of the largest railway network in the world. In the recent years the indian railways has implemented fast track service trains with the conversion of the meter gauge into the broadgauge .
While the Gauge conversion works takes place number canals and rivers interface the railway line and those are bridged by the Post tensioned girders or post tensioned slabs. The PT application has become inevitable and it has find application even though the locations are remot.
UTRACON has been shortlisted by the southern Railways / URC / Bharat Engineering to carry out the PT works for all the required girders on the gauge conversion works. We have successfully completed all the PT works in the gauge conversions.
Utracon scope with URC: Guage conversion from Trichy to Thanjavur (2nd line track) and Aranthangi to Karaikudi.
Utracon scope with Bharat engineering: Gauge conversion from Pattukottai to Aranthangi.
For further details:
Utracon Structural Systems Pvt Ltd
Ph: +91-44 2446 8001/2/3