Abstract:
Offsite construction is a type of construction in which structures or members are built offsite or in factory and then assembled on site. It has many benefits as well as challenges. These techniques are being adopted worldwide but Pakistan has yet to see a full-blown utilization of the offsite construction. In this research, comprehensive literature review is done to find the benefits and challenges of offsite construction. The questionnaire was developed to find the perceptions of consultants and contractors in Pakistan about offsite construction. A total of 140 responses (70 from consultants and 70 from contractors) were collected. T tests at 95% confidence interval and linear regressions were done to analyze data. And then case study of a construction project was taken to compare cost and duration of onsite traditional and offsite construction. Findings show that consultants and contractors are of the view that reduced duration is the most important factor driving the use of offsite construction. Decrease in project duration, skilled workers’ demand, onsite disruption, negative impact of other operations, labour congestion on site and increase in labour productivity, safety, design efficiency, management efficiency, overall savings in cost are possible benefits of offsite construction. Transportation feasibility and limited options for design are challenges of offsite construction. Sub groups comparisons show linear relationship of 20.9% in residential, 14.7% in infrastructure, 0% in commercial and 1.2% in industrial sectors between consultants and contractors suggesting a lower level of consensus. Further, no statistical relationship is found between consultants and contractors in Pakistan construction industry regarding the benefits and challenges. From case study it is clear that offsite construction takes 7.1 % less duration and 7.4 % less cost as compared to traditional onsite construction in Pakistan. Conclusions are drawn and recommendations are made based on these findings.
