Dynamic Minimum Lag Relationship - Construction Project Scheduling and Control - page 333

B

A

Lag Time

Activity B has nonlinear (parabolic) productivity

(a)

B

A

Time

Lag

Activity A has nonlinear (hyperbolic) productivity

(b)

Work
stoppage

A B

Time

Lag

Activities A and B have linear productivities,
but activity A has a work stoppage

(c)

Figure 12.3 Examples in which the successor (activity B) has gotten ahead of the
predecessor (activity A) at some point, although there was no violation of the traditional SS
and FF relationships

Since this is an “inequality,” RD B has to be equal to or greater than the right-hand
side. So, in a software program situation, the program calculates the minimum value
for RD B but the user can override it with a larger, not a smaller, number.
It is also possible—although not recommended—to allow the user to give the
RD B . In this case, equation 12.3 will solve for AD B , that is, will limit its value:

PC A ⋅ RDB − L

1 − PC A

AD B ≤ (12.5)