A work process model of industrialised building system in Malaysian construction industry

The lack of mechanisation and modernisation adoption, unavoidable dependence on labour workforce, the lack of skills and experience, as well as the reliance on foreign workers, were amongst the challenges in improving the industrialised building system (IBS) in the Malaysian construction industry (MCI). Furthermore, the techniques and performance of the labourers in precast concrete for this study referred to hereon is Industrialiased Building System Precast Concrete Consruction (IBSPCC) are similar to those of the In-situ Concrete Construction (ICC), resulting in unnecessary repetition, which consequently creates non-value-added (NVA) activities that could affect productivity growth. To address the issues above, a significant improvement towards the IBSPCC, encompassing the production and the assembly work processes, may be achieved by adopting the lean approach, through which the value-added (VA) activities, NVA activities, and non-value added but required (NVAR) activities can be distinguished. Therefore, this research aimed to develop an IBSPCC work processes model, covering the reinforcement, precast moulding, concreting and assembling, using the lean approach as a strategy for work process improvement. To evaluate its effectiveness, each work process was compared against those of the ICC method, based on the duration in producing reinforced concrete (RC) structural frame (columns, beams and slabs), gang size, as well as the measure of their productivity level in terms of output per man-hour. Mixed methods study was undertaken, to provide comprehensive answer to the research question. Through this study, there were contradicted findings between questionnaires and the observation for both the IBSPCC and the ICC methods, in terms of the duration and gang size, for the reinforcement, formwork or precast moulding and concreting work processes. This also includes the findings obtained through the evaluation of productivity output per man-hour that indicates certain work processes of the IBSPCC has less output as compared to the ICC method. This confirms that some repetition of the ICC method occur in the IBSPCC work process. In other words, reliance on labour workforce and minimal machinery usage still persist. The only difference is in the location of producing the components, transportation, precast moulding and assembly work process. It was also found that a number of NVA activities are comparable with the seven classic categories such as overproduction, waiting, and unnecessary inventory, although the causes may be different. Surprisingly, a majority of the IBSPCC manufacturers have had an opposing view of overproduction as one of the NVA activities. To them, the more that they are able to produce, the better is the performance, which is in contrast with the lean approach. Apart from that, several NVA activities especially during assembly work process were uncontrollable due to procedures, working method, technological development or actions that need to be undertaken by others in the supply chain. This makes the mitigation of NVA activities more challenging. Due to the need for elimination or minimisation of NVA activities, the work process model has been developed, incorporating several strategies such as an optimisation, multi-tasking, standardisation, planning layout, just in time (JIT) and Kanban, which all have resulted in a simplified work process, less time, an improved labourers’ working pattern and has a high potential to increase productivity. Although the case studies presented here cannot be generalised to all IBS classifications, the work process models could be a starting point to generate preliminary ideas on how the lean strategies can improve the IBSPCC work process. It is also hoped that this research will potentially increase awareness and knowledge regarding the lean approach amongst the IBSPCC stakeholders.