Studying time presence on site as an indicator of productive time use by construction workers

Productivity in construction is relatively low compared to other industries. This is particularly true for labour productivity. Problems that contribute to low labour productivity are often related to unorganised workspace and site logistics, and inefficient organisation of labour, materials and equipment. In terms of time use site workers spend time on various activities including installing, waiting, walking, transporting, measuring etc. Various studies have indicated different distributions of the time use per activity of site workers. In lean production terms time use could be categorised in three categories: value-added, necessary but non-value-added, and wasteful. The research reported in this paper has endeavoured to measure the improvement of the time use in those three categories when work organisation and site logistics were reorganised. The case study reported included specific logistics measures taken aimed at expected productivity improvement. This included just in time deliveries to work spaces of workers outside work hours aimed at reduced time used for walking and transporting. The study of this research investigated time use effects of few subcontractors based on interviews and on automated tracking of workforce. The interviews gave insights in the time build-up of work days of subcontractors that indicated improvements of value-added time use per day thanks to just in time deliveries. The automated tracking indicated less walking by site workers than the specific subcontractor would expect in case materials were delivered traditionally per day from ground level. In the new situation the materials were distributed to the floors in weekly batches by dedicated logistics workforce. The time measurements of the study demonstrated improved time use of site workers. However the discussion of the results underlined that the particular characteristics of individual projects may well have an impact on the productivity study result and more comparative studies between projects should be helpful.