Relationship between Floor Number and Labor Productivity in Multistory Structural Work: A Case Study

Abstract

Construction activities are repetitive from floor to floor in multistory building construction. Labor productivity may neither reach 100 percent of the normal level at the very first floors nor the very top floors. Nevertheless labor productivity may follow a certain pattern as construction activities progress. This research aims at exploring the relationship between floor number and labor productivity in multistory structural activities, namely formwork installation and rebar fabrication/installation. The case study methodology and learning curve theory are adopted for this research. Records from the structural works of an apartment building were analyzed to calculate floor number-based labor productivities for the two investigated activities. The unit rate of the formwork activity reduced more than 50 percent in the first five floors. If the first cycle (floor 2) is omitted, the straight-line learning curve model shows a learning rate of 83.5%. Productivity of the formwork activity tended to level off in the remaining thirteen floors. The unit rate of the rebar activity was prone to reduce in the first fifteen floors. If the first two cycles are omitted, the straight-line learning curve model indicates a learning rate of 83.6%. If only the first cycle is omitted, the learning rate of the rebar activity is 87.9%. Productivity of the rebar activity tended to decrease in the last three top floors though data points were not adequate to confirm such pattern.