Quantifying productivity loss due to field disruptions in masonry construction

Many research studies have proven that productivity loss is the result of several factors including excessive change orders, long periods of overtime, poor field management and severe weather. These factors generate further disruptions affecting masonry productivity, and result in productivity loss or additional work-hours to be required to perform masonry work. Unfortunately, estimators have had difficulties in quantifying this productivity loss because no data of normal productivity without an impact of field factors is available for determination of such loss. The quantitative evaluation of productivity loss due to field disruption in masonry construction is therefore needed. This research study presents a quantitative evaluation of productivity loss due to field disruptions, based on a national survey. This study is intended to be a reference tool for masonry practitioners in construction claims, construction estimating, planning and scheduling. The primary objective of this study was to quantify productivity loss caused by sixteen different field disruptions based on three levels of standard field conditions for masonry building construction. With respect to this objective, a model used to estimate productivity loss or additional work-hours due to the impact of field disruptions was developed, based on a national survey conducted in the year 2000. A total of 950 questionnaires were randomly distributed to masonry contractors throughout the U.S. , and 152 questionnaires were collected. The model presents an averaged percentage of productivity loss due to field disruptions, along with a range of possible loss that may exist. Masonry practitioners can employ the results of this survey to determine additional work-hours needed to perform the masonry work in field conditions that differ from original expectations. Through a second research survey, conducted in Texas, the model was tested using five masonry construction projects facing field disruptions. It was found that the differences in the estimated and actual percentages of productivity loss ranged from −2 to 19%. In this dissertation, research procedures, conclusions, and recommendations for industry and future research are also discussed.