Case Study on Production System Design with Discrete Event Simulation for Bangalore Metro Underground Project

Construction processes are difficult to plan and control due to the numerous uncertainties and complex resource interactions; therefore ‘launch and hope’ approach is often adopted, leading to significant waste in the process. Discrete event simulation (DES) helps model the behavior of production systems to understand the combined effects of all factors influencing the process, which can lead to significant savings. Executing concrete pours for infrastructure projects in overly populated old urban areas is a very complex exercise owing to the challenges of congested roads, hours of restricted traffic movement, greater transit distances, resource constraints, uncertainties in operating conditions and stringent quality control norms. Logistics planning with optimized resource allocation is further complicated when the resources such as batching plants, transit mixers and boom placers are shared between multiple project sites managed by different stakeholders simultaneously. The case study describes the application of DES for designing the process to yield smooth flow and optimal resource allocation. The lean construction concepts such as pull planning, establishing flow and takt time have been imbibed in the process for realizing the most optimum and resilient design. Emulating the ‘Last planner system’, several scenarios were studied with all stakeholders virtually with the aid of ExtendSIM software before the actual execution, which led to significant savings in time and cost. Further, following the principle of Gemba and Kaizen, the field data was captured with the aid of several digital tools and analyzed. Several brainstorming sessions with critical stakeholders lead to continuous improvement and further savings in time and cost.