THE CONSTRUCTION OF A HOUSING PROJECT WITH REPETITIVE WORKING PATTERNS PART 1 WORKING WITH DIFFERENT SCHEDULES BETWEEN CPM AND RSM

Abstract

Repetitive construction such as housing development projects can be scheduled by various methods including Critical Path Method (CPM) and Repetitive Scheduling Method (RSM). This paper presents the effects of using different work schedules between CPM and RSM by using STROBOSCOPE to simulate the construction of 40 housing units based on the data from a real construction project. The result shows that different scheduling criteria result in different activity schedules and critical activities. Given the first scenario which work is performed as planned, CPM schedule has shorter project duration with less average throughput time compared to those of RSM.  However, with unbalanced activity production rates, CPM schedule results in work discontinuity leading to high value of total worker idle time, while RSM schedule results no idle time at all.  The second scenario is actual work condition.  Activity durations are input in the form of density functions based on data collected from field.  The result shows that the variations of activities’ durations have high impacts on CPM in all aspects.  Project duration, average throughput time, and total worker idle time become double.  However, these particular work conditions have slight impacts on RSM.  This is because, to promote work continuity, the start dates of many activities are delayed, and this creates gaps between two adjacent activities.  These gaps turn into time buffers which will alleviate adversity of delay to the successors. In the last scenario, controllable causes of disruption are assumed to be diminished. The results of this scenario are relatively similar to those of the first scenario as, in this case study, most of obstacles are avoidable.