Work density method for takt planning of construction processes with nonrepetitive work

A new method is presented for construction process planning. It is based on the concept of work density and called the Work Density Method (WDM), two terms coined for use in this context. Using the WDM, planners create one-piece workflow by dividing work space into zones while assigning each zone exclusively for each trade to complete their work, with trades working in consecutive process steps, each one taking up to the same fixed amount of time. The method supports development of a plan (using takt or not) for repetitive as well as nonrepetitive work thanks to work density serving as the common unit to describe workload. The WDM is an iterative method using work structuring to decide a sequence of process steps, zone the work space while lowering the peak of the cumulative work density (i.e., workload peak), determine a lower bound on the takt that can be met, and verify this meets customer requirements. The method was developed experimentally on a live project. This paper rationalizes the use of work density in planning, illustrates the WDM using examples, presents a paradox, and suggests method enhancements. The contribution to knowledge is the formulation of a new planning method that augments existing planning methods.