Controlling activity interval times in LOB scheduling

A new scheduling method is presented in this paper which overcomes the inability of the line of balance (LOB) method to control the interval times between adjacent activities in a repetitive construction unit. The interval times are analysed and then expressed as functions of the number of repetitive construction units, the difference between construction times of adjacent activities and the sequence of repetitive construction units. In order to overcome the LOB problem, this paper presents a new scheduling method, the multistage linear scheduling (MLS) method, based on the concept of a multistage decision process. With the MLS method, the project's completion time is smaller or equal to that estimated with the LOB method. The sum of construction times of each activity in all units is the same as that estimated with the LOB method. However, no interval times are generated. The adjacent activities in a repetitive construction unit can progress continuously (not allowed under the LOB method). Therefore, the MLS method can be used to schedule a repetitive project which has necessary practical constraints on the interval times. This results in the retention of construction quality, safety and efficiency.