Technique for accounting for the decrease in labor productivity due to workspace overcrowding

Abstract

In civil engineering, delays are ubiquitous. They cause significant economic damage. One way to prevent deadline disruption is to lower the duration of tasks by increasing the number of workers on critical path activities. However, when the number of workers increases above a certain level, the duration stops decreasing due to the interference between workers that occurs in a limited work space. This situation is called “work space overcrowding”. To determine the number of workers at which work space overcrowding occurs, as well as to improve activity scheduling accuracy, the author has developed a technique for accounting for labor productivity decline due to work space overcrowding. During the development of this technique, an analysis of existing approaches was carried out. Their shortcomings in practice are revealed. Then, the factors of productivity decline associated with overcrowding are identified. These factors are divided into two categories: “spatial” and “socio-psychological”. Two models are developed based on a mathematical formalization of these categories. The criterion for choosing between the two models is the intensity of workers' movements. The technique was successfully verified using peer review by specialists in nuclear power plant construction. It was found that the technique accurately reflects the general nature of labor productivity dependence on the number of workers: constant levels of productivity up to a certain number, followed by decreasing levels of productivity, at accelerating rates, above that number. However, application of the technique provides only a rough approximation of this dependence in quantitative terms. This is compensated for by the technique’s simplicity, requiring a limited number of inputs to produce a meaningful result. Finally, applying the technique to two specific cases, a recommended limit of the increase in the number of workers is determined for both. In the future, the technique can be applied to a wider range of construction activities.