Mumbai Metro Line 2A is being constructed by MMRDA between Dahisar (E) and DN Nagar achieved its one of the most difficult milestones of launching steel girders on Western Railway line between Dahisar & Mira Road railway stations.
MMRDA conveys its sincere thanks to Western Railways and MCGM for their continuous support through these last 2 years and especially the support given in the last one month. It is worth mentioning here that generally all critical construction works are stopped during the monsoons but here at the behest of MMRDA, MCGM agreed to give an extraordinary permission to make pipe culverts across VH Desai Nallah and Avdhoot Nagar nallah, which facilitated placement of cranes for this work. The officers of Western Railways gave extraordinary support in approval of GAD, structural drawings, erection methodologies and traffic block.
- The design & drawings have gone through multiple stages of review and approval.
- First the design was done by designer of the contractor which was checked by DMRCs detailed design consultant (DDC), M/s Aecom & further proof checked by IIT Mumbai.
- Then it was again reviewed by DMRC design cell and finally approved by western railways.
- The required approvals from the Office of Commissioner of railway safety were also received within a week.
- NP-4 pipes were used in making the pipe culverts so as to take load of self weight of cranes, counterweight and load of girders.
- Moreover, due to incessant rains from 20-22 Sept, the entire area got slushy.
- Therefore, area was developed using a mixture of fine and coarse aggregates so that no voids are left in filling and area is well compacted to take such heavy loads of crane outriggers.
- Initially, the plan was to launch 02 out of 03 girders weighing 36T each, total 72MT.
R A Rajeev, MMRDA Commissioner commented: “We are glad that despite having a lot of onsite complications including incessant rainfall the city witnessed in past a few days we were able to complete the task. MMRDA is now one step closer to the trial runs on Metro Line 2A that are expected to begin in January 2021 with the completion of this work. The timely launching of girder in coordination with Railways and BMC authorities taking all necessary precautions and safety measures also tells how the working patterns in government agencies have changed.
- However, the first launching got completed in just 45 mins.
- Then entire block of 03 hrs 30 min. Was optimally utilized and third girder was also launched and safely braced during the same block.
- These steel girders comprise of three plate girders with a combined weight of 110 MT.
- These girders were fabricated at a fabrication yard located in Hyderabad with precision cutting, hole punching and welding machines.
- Automatic Beam Welding machines, CNC (Computer Numeric Controlled) drilling, CNC cutting machines are used. All parts of girders have been metalized and aluminum painted as per RDSO specifications to prevent from rusting.
- The girders were launched during traffic and power block hours between 0005 hrs to 0335 hrs by using two cranes of 500MT and 300MT capacities with another 400MT crane as standby for any emergency situation.
- A no. of other machineries like 08 manlifters, 03 pick and carry cranes, 2 nos. 50MT cranes and 04 multi-axle trailers were also deployed to complete this work within the block period.
- The girders have been placed on precast post tensioned pier caps. After erection of girders, work of cast in-situ deck slab shall be taken up on already placed decking sheet and thereafter RCC parapets will be erected to complete the superstructure.
- It is also pertinent to mention that substructure of this metro span has been designed to take derailment impact load of railway trains and thus without having any impact on superstructure of metro above.
- The entire metro alignment of approx. 1200.0m is running adjacent to Dahisar flyover on service road and piers are aligned such that there is a gap of only 400-500mm between the face of pier and edge of flyover so that minimum width of service road is consumed for metro construction.
- Also, height of bottom part of metro pier cap has been kept at min. 5.5m above flyover as pier IRC guideline so as to ensure safe vehicular movement on flyover.
- Due to Covid19 pandemic, hard copies of documents could not be submitted in the Office of Commissioner, Railway Safety.
- However, he was kind enough to grant approval through eoffice within a week’s time. Similarly, most of the work of checking drawings/designs were done by the Chief Bridge Engineer/WR and DRM through e office only at a much faster pace than the normal functioning.
- Thus, the effect of COVID 19 was completely overcome by WR officials & the office of CRS Western Circle through modern technology.
The completion of this work is a major milestone in MMRDA’s target for trial runs of metro Line-2A by January, 2021.
Source: MMRDA- Press Release