Application of Six Sigma on Rail Construction Project

Viraj Parekh1 , Kushal Solanki1 and Nishit Prajapati1

1 Civil Engineering Department, Institute of Technology, , , India

Abstract. Six Sigma is a Quality Improvement Technique widely used in Man- ufacturing Industry. Application of Six Sigma is yet to be explored exhaustively in the field of Construction. This study explores the possibility of application of Six Sigma in METRO Rail Construction. This paper defines and analyses Con- struction Performance of Pier Construction in METRO Rail Project of Ahmed- abad using Six Sigma Technique. A stretch of 4 km from North-South Corridor is selected for the study from APMC to Shreyas. The data such as Work Break- down Structure, List of Activities, Time of Activities, Dependency of Activi- ties, Construction sequence etc. is collected and analysed using software Pri- mavera and Minitab. Process Capability Analysis is used to determine how well an actual process meets a set of specification limits in a scheduled plan. Data is represented and analysed by preparing different charts and graphs such as I – Chart, Moving Range Chart, Capability Histogram and Capability Plot. A com- parison was done between the actual works done at the site and the schedule planned for the progress to calculate the Sigma value. It is found from the result that the calculated Sigma value is near to the ultimate Sigma Level. This work provides valuable insights for the implementation of Six Sigma Technique in the Construction Industry. Six Sigma Technique can evaluate the quality of cur- rent construction activity and quantify the improvement goals so as to control succeeding critical activities for the project. Improvement in Quality of Con- struction can be observed at large extent with the application of Six Sigma Technique. Six Sigma Technique can be linked with Lean Principle.

Keywords: Six Sigma, Construction Project Management, Quality Manage- ment, Lean Construction

1 Introduction

The Six Sigma concept is derived from bell-shaped curve. Theoretically, this bell- shaped curve has been proven very useful as numerous natural continuous phenomena seem to follow it or can be approximated by it. [1] Six Sigma is used in Manufactur- ing Industry since last two decades to monitor and improve the quality aspect in the process. The Six Sigma concept emphasis on improving the Process Performance rather than focusing on final output only. Process Performance can be evaluated by DPMO (defects per million opportunities). To achieve the sigma level at six, the value of DPMO is 3.4. [5]

© Springer Nature Singapore Pte Ltd. 2020 567 C. Ha-Minh et al. (eds.), CIGOS 2019, Innovation for Sustainable Infrastructure, Lecture Notes in Civil Engineering 54, https://doi.org/10.1007/978-981-15-0802-8_89 568 V. Parekh et al.

The application of Six Sigma in Manufacturing Industry has been proven quite use- ful. So it was applied in Construction Industry as well, but at small scale projects such as a residential building to improve the quality of internal finishing work [4]. Six Sigma principle was applied in lightweight partition walls also to determine and im- prove the key input variables affecting the cracks [2]. Application of this technique is yet to be explored in huge Infrastructure Projects like Metro Rail Construction. There- fore, to assess the application of Six Sigma at this level, Ahmedabad Metro Rail Pro- ject was selected for the research purpose. Ahmedabad Metro is an under construction mass transit system being built for the Ahmedabad City in the state of , India. It is being built by Gujarat Metro Rail Corporation (GMRC) Limited; a Special Purpose Vehicle constituted to implement all the Metro Projects in the state of Gujarat. The Ahmedabad Metro Rail Project is di- vided in Phase-I and Phase-II. Phase-I have the total span of 39.259 km which is the combination of underground tunnel construction (nearly 6km length) and elevated construction (nearly 32km). The North-South Corridor and East-West Corridor of the Metro Rail will connect four corners of the Ahmedabad City with 32 stations. For the research purpose, 4 km long stretch in the East-West Corridor was selected from APMC to Shreyas.

2 Methodology

DMAIC i.e. Define, Measure, Analyse, Improve and Control is an integral part of Six Sigma Process for continuous improvement. DMAIC is a five-step process where one has to define the key variables in process at first place, measure the process per- formance at second place, analyse the data collected and find out the root- cause at third place, improve the process after rectifying the root-cause at fourth place and finally to control the improved process. Application of Six Sigma starts with DMAIC methodology to find out the value of DPMO.[3] In contrast to the manufacturing industry, construction work is characterised by its fragmented and project orientated work process. Manufacturing Industry observes repetitive work but Construction is unique from Project to Project. To assess the qual- ity of construction project, the triangle of project management highlights on three aspects: Time, Cost and Scope of the project. Time overrun leads to cost overrun and overall the quality of entire project is suffered. We have consider time as an important aspect and study of critical path of this project was done. Based on this study, three important activities were identified having float value zero. These activities are Piling, Construction of Pier and Construction of Expansion Joint. Piles constructed in Metro Projects are about 25-30m in depth. Thus, it is difficult to find defects after the construction of a pile is done. Construction of Expansion Joints are scheduled after the launching of girders which was yet to be done. Pier construction was the only activity on which this study could be done. Pier defects can be easily diagnosed as they are visible. In this study, original schedule and actual time of construction of pier is taken to measure the process performance. Planned data was available and actual data was collected by onsite visits. To analyse the data, Process