Could you please tell us what the "two-level planning" is?
The construction and installation schedule may contain a different number of items depending on the scale of a construction project. Sometimes, at large facilities, the number of items of the construction and installation schedule counts thousands and tens of thousands. For convenience, the schedule is divided into parts.
A Spread is part of an object under construction, the construction of which is autonomous and technologically independent. Construction and installation works of the Spreads are performed independently of each other. For example, two separate buildings can be considered as different Spreads.
Work Zone - is a logically marked-off part of the construction object. The entire volume of work of a certain Spread is divided into parts convenient for the effective organization of planning and monitoring of the construction and installation works. Each such part is a Work Zone.
Planning levels. The top level of planning is planning by Work Zones. The lower level of planning is planning within each Work Zone.
At the top level of planning, the links between the Work Zones are determined, and the planned time for performing construction and installation works for each Work Zone is set. A Gantt chart is formed, and the critical path for the construction of an object is calculated.
The lower level of planning is necessary for organizing work within specific Work Zones. It can be used to specify the period of work on this Work Zone.
Before calculating the top-level schedule, the sequence of work on the Work Zones is indicated by forming temporary links between predecessors and successors. If it is necessary to pause or advance relative to the start date of work on the Work Zone, the shift of work in time is corrected by the shift factor.
At the top level of planning, temporary links can only be formed between Work Zones and cannot be established between a Work Zone and an item inside another Work Zone, or between a Work Zone and a line - the name of a group of Work Zones.
At the lower level of planning, temporary links can only be formed within a Work Zone and are established between assignments.
Formation of the schedule includes creating a planning scheme in the form of Work Zones with their filling in the "Work Breakdown Structure" window with the existing Construction blocks from the "Project Structure" window.
Distribution of the volume of work by the Work Zones is carried out by linking each assignment with the selected Work Zone. An assignment can be linked with only one Work Zone. When distributing assignments by Work Zones, information on the amount of work is generated in each Work Zone.
The Target Schedule of construction and installation work (CIS) is formed at the beginning of the project at the preparatory stage for the construction. It establishes the sequence and deadlines for the execution of the works combined in Work Zones. At this stage, "enlarged" planning (top-level planning) is performed - the planning scheme is formed in the form of a list of Work Zones with time ties between them. The system contains a directory of planning scheme templates for typical construction objects.
Within each Work Zone, we can plan the work in more detail. This is the lower-level planning, in which a list of works and their sequence within the Work Zones are formed. To do this, Work Zones are “filled” with assignments (individual works) from the structure of the construction object. The Target Schedule is considered complete when all assignments from the structure of the construction object have been spread out across the Work Zones of the CIS.
Operating Schedule - is the result of adjusting the start and end dates of the Target Schedule during construction (operational planning). The target and operating construction and installation schedules have a common list of work zones and assignments (works) within each work zone, the same time ties between the items of the schedule, but different start and end dates of the works.
When creating a schedule, the start date of the work is indicated.
At the top level of planning, it is necessary to make time ties between the work zones, to introduce data on the delay or shift of work, and to indicate manually the number of days for the work zones in the "Duration" column.
Further, on pressing the "Calculate plan" button, the system calculates the start and end dates of work for each work zone. The system applies the calendar by default to calculate the dates for the work zones.
At the lower level of planning, within the work zone, various methods of calculating and forming the planned deadlines for completing individual assignments can be used.
The date of commencement of work on a particular work zone is defined in the top-level schedule. The time ties between assignments or groups of assignments are established that determine the sequence of their execution.
One of the calculation methods is selected depending on the information available for the assignments. If you know the planned daily intensity of work on assignments, the calculation method "By labor intensity" is selected. Daily intensity is the amount of work to be performed per day.
If the labor intensity on assignments and the number of workers at the construction site are known, the calculation method "By labor intensity" is selected.
For assignments, you can set your own calendars, then the system will calculate the deadlines taking into account weekends. If necessary, you can enter the dates of suspension and resumption of the assignment.
When calculating the time to perform work on a Work Zone, the part of CIS inside the Work Zone is formed.
First, the sequence of assignments is indicated by forming time ties between predecessors and successors. Then the schedule inside the Work Zone is calculated.
If it is necessary to pause or advance relative to the start date of work on an assignment, the offset of work in time is corrected by the offset factor.
In real construction, the Schedule may change every month (i.e., the dates of the operating schedule may change). The snapshot saves the current information. Periodically taking snapshots and comparing them, you can analyze how efficiently the planning department or construction workers are performing. In order to see changes in the Schedule when comparing the snapshots, you need to take snapshots before and after making changes.