How can make study explain needed for night shift in construction work ?

It can be done by "what if" evaluation.

Create project version with additional shift and compare with original version. The difference will show what can be achieved adding new shift.

Beware that some software cannot correctly model shift work when the duration of the activity is driven by how much work is produced by the resources on different shifts. I understand P6 cannot deal with this issue unless new versions were updated to correctly model shift work.

You can try yourself a simple scenario.

Activity 1 500cm rock excavation

Resource 1 production 10cm/hr  and works Monday, Tuesday and Wednesday 10hrs/day

Resource 2 production 15cm/hour and works on Wednesday, Thursday and Friday 10 hrs/day

If activity starts on Monday:

Monday =>> Resource 1 will produce 100 cm

Tuesday =>> Resource 1 will produce 100 cm

Wednesday =>> Resource 1 will produce 100 cm

Wednesday =>> Resource 2 will produce 150 cm

Thursday =>> Resource 2 will produce 50 cm in about 3 hours

Activity will take 3 days 3 hours.

If activity starts on Wednesday : 

Wednesday =>> Resource 1 will produce 100 cm

Wednesday =>> Resource 2 will produce 150 cm

Thursday =>> Resource 2 will produce 150 cm

Friday =>> Resource 2 will produce 100 cm in about 7 hours

Activity will take 2 days 7 hours.

If your software is not capable of modeling the above, simple shift work on a single activity, then you are using the wrong tool. Every time the activity is delayed, the distribution of work is shifted, when you have many such activities and work on different hour shifts, different days it can become quite complicated. Distributing work by hand is nuts.

For a single shot you can use incapable software with manual distribution of work among shifts.

Regards,

Rafael

I have idea to take the update for the project for three months and calculate delay in the project and then take factor for this period and assume it will be constant to the end of the project and show delay periods for the project at the end of contract period, and put say to the management for example one months to work double shift and do this process every  three months to be with schedule 

Your suggestion of including trends instead of merely comparing a schedule using shifts against a projection of the actual schedule without considering trends is good, very good.

By merely changing activities duration and resource loading to those activities showing a delay trend using as the basis the latest update you can forecast both "what if" schedules.

I would only add a duration factor to such repetitive activities you have some defined trends, not sure about a ballpark application of the delays to the whole job as if these can be extrapolated to every activity.

dear all,

  the need the

the need of the night shift is one of the actions to be taken to mitigate the delays and bring the project back to the plan.

when a project is in delays the conrtator can do the followig in order to mitigate the delays:-

increase the resources

work in log shift

work bouble shift (day and nieght)

work durig the public holidays

so the night shift is a must if the project is in delay and by introducig the update progress report you can varify the delay status of the project ad you can offer of one or more of the above mitigation action other wise the project will contiue to be in delay.