Dynamic Minimum Lag Relationship - Construction Project Scheduling and Control - page 342

Parking Lot
12

Landscape
10

Figure 12.9 A situation in which the DML relationship cannot be used in lieu of the FF
relationship

CHAPTER 12 EXERCISES
1. What is the main idea of DML? What makes it different from the logic relation-
ships of the precedence diagramming method (PDM)?
2. Give two examples of construction work (combination of 2 to 4 activities, each)
for which DML would be suitable.
3. What are the limitations of DML?
4. For the following two activities:

Activity Title Original Duration (days)

A. Trench Excavation 18

B. Laying Pipe 13

we need to maintain at least a 1-day lag between the two activities at all times.
The activities are contiguous. Assume activity B (Laying Pipe) to be linear. What
is the minimum RD B according to the DML equation in these stages? What is
the RD B that you should consider, taking into consideration both the DML and
the FF relationships?
a. After 5 days, activity A is 25% complete. Activity B started two days early, that
is, AD B = 1day
b. After 8 days, activity A is only 30% complete. Activity B's AD B = 4days.
Assume that activity A will finish on time.
c. After 10 days, activity A is still 40% complete. Activity B's AD B = 6days.
Assume that activity A will finish on time.
d. After 13 days, activity A is 70% complete. Activity B's AD B = 9 days. Assume
that activity A will finish on time.

5. What is the challenge in taking the lag in the DML relationship as a percentage
of the predecessor's duration?
6. Give an example of an SS relationship that should not be replaced by a DML
relationship.
7. Give an example of an FF relationship that should not be replaced by a DML
relationship.