Influence of buildability factors on rebar installation labor productivity of columns

Buildability is one of the most important factors influencing labor productivity. A thorough investigation of the literature, however, revealed a dearth of research into its effects on the labor productivity of an integral trade of the in situ reinforced concrete material; namely, rebar installation, especially at the activity levels. Because reinforced concrete columns are among the major encountered activities on construction sites, the objective of this research is to explore primary buildability factors influencing their rebar installation labor productivity. To achieve this objective, a sufficiently large volume of productivity data was collected and analyzed by using multiple and categorical-interaction-regression methods. As a result, the effects of the variability of column sizes, rebar diameter size, reinforcement quantity, and column geometry, are determined and quantified. Although the extent of the size variability and circular geometry show significant negative impacts on the labor efficiency of the operation, the rebar diameter size and quantity of reinforcement installed exhibit positive effects. The results obtained may be used to provide designers and construction managers with feedback on how well the design of this activity considers the requirements of buildability, and the consequences of designers' decisions on the productivity of the installation operation. Moreover, a set of practical recommendations is presented, which upon implementation can improve the design buildability level of the activity explored and, thus, translate into higher labor productivity and more efficient planning and utilization of operatives.