Abstract
Sewer construction in urban areas often requires nighttime operations to meet project schedules and to reduce possible negative effects of construction work on traffic operations. Although several studies investigated the correlation between daytime and nighttime construction productivity, there is a limited understanding of how shift work may influence productivity in sewer construction projects. This research examined the labor productivity of 10 activities typically performed in both day and night shifts in sewer construction. The research employed Levene's test and t-tests to analyze the data collected from eight sewer construction projects in Ho Chi Minh City, Vietnam. The results indicated that (1) pavement cutting and timber piling were more productive in daytime operations, whereas steel sheet piling and manhole concreting were more productive in nighttime operations; (2) no statistically significant difference exists in productivity between day and night shifts for the following activities: excavation, form installation, rebar installation, pipe laying, sand filling, and asphalt paving; and (3) the productivity of pavement cutting, excavation, timber piling, steel sheet piling, pipe laying, and asphalt paving was higher in partial road closure than in full road closure methods. These statistical results were verified and validated by the experienced site managers/ engineers through eight structured on-site interviews. This research contributes to the construction productivity knowledge by providing empirical results of daytime and nighttime operation productivity in sewer construction. It is expected that practitioners can use these results to focus proper attention and resources for day and night shifts in sewer construction projects. (C) 2014 American Society of Civil Engineers.
