Regarding predessors & Sucessors

the client wrote there are many activities thathave only ss succesors(s).this is not good scheduling practice and should preferably be avoided.

Is there any criteria that we want to use FS,FF,SS or SF in these we have to use fs more?

Z
Zoltan Palffy 👤 Member for 16 years 10 months

not only does the GSA use a 90% threshold but the DCMA 14 point schedule asessemtn also states that 90% of the activity relationship types should be of the FS type. That means that there can be 10% of the SS or FF relationship.

Techanically using only a ss will flag the activity has not having a successor. What you can do is create a compound or combination relationship. On the activities where you know only have a SS successor and add successor of the same activity id but with a FF relationship. The SS successor will tie down the start of the activity while the FF successor will tie donw the end of the activity.

Z
Zoltan Palffy 👤 Member for 16 years 10 months

not only does the GSA use a 90% threshold but the DCMA 14 point schedule asessemtn also states that 90% of the activity relationship types should be of the FS type. That means that there can be 10% of the SS or FF relationship.

Techanically using only a ss will flag the activity has not having a successor. What you can do is create a compound or combination relationship. On the activities where you know only have a SS successor and add successor of the same activity id but with a FF relationship. The SS successor will tie down the start of the activity while the FF successor will tie donw the end of the activity.

T
Tijo Kurian 👤 Member for 7 years 10 months

As per GAO most of the relationships in  a detailed schedule should be  Finsh to Start. Generally  more than 90% activites with FS relationship without any lag is preferable. Other relationships SS and FF also can be used for paralel works without any dangling logic ( Open ends ). 

S
Santosh Bhat 👤 Member for 21 years 1 month

The problem with using too many SS linkes as successors is that any delay to the firsty activity, will not lead to a delay in the second activity, and so on throughout the whole network.

FS links are the ideal relationships as they will have a consequential affect upon subsequent activities due to delays, or duration elongations earlier in the network. However, SS & FF links are equally valid if there is a degree of parallelism between activities.

As SS successors are effectively open-ends, it's good practice to also include a corresponding FF successor for every SS successor.

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