The efficiency of Lean at work in the Nagpur Metro

01 Nov 2022

Nagpur Metro Phase 1 consisted of two corridors, North-South and East-West, with a total length of 41.7 km. Of this, 17.087 km (41 per cent of the viaduct) was awarded to Afcons in the Reach 2 (North-South corridor) and Reach 3 (East-West corridor) stretches. Afcons executed the Reach 2 package in the North-South corridor, which consists of a 5-km double-decker structure and 1.7-km metro viaduct structure that starts from Automotive Square on Kamptee Road and ends at Sitabuldi.

The double-decker flyover structure consists of two decks: flyover level and metro level. The decks are constructed with precast segments. The flyover level consists of two segments: spine and wings. The team adopted Value Stream Mapping (VSM) to improve the cycle time by ~50 per cent, from 28 days to 14 days. Some key interventions were:

  • Improvement in sequence of construction operations allowing for simultaneously launching wing segments and launcher (after erection of three cantilever arms)
  • Analysis of idle time to optimise use of trailers for transportation of both segments and wings
  • Simultaneous operations for wings alignment, shutter fixing and rebar fixing
  • Minimising time at site operations through use of boom placer instead of stationary pump and higher grade of concrete
  • Use of manlift for stressing to decouple working site and ground traffic.

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