Civil Engineering Reference
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the data date = 10). If the project had not slipped, the TF for activity H would
have been = 11 − 4 = 7, but the slippage of the project by two days made the
H's TF = 7 + 2 = 9 days. Activity L had TF = 6 days and still the same value
after the update because the driving relationship comes from activity G, which
was delayed by 2 days. Activity M had TF = 11 days, but after the update,
it became TF = 11 + 2 (project finish date slipped)−2 (delay for activity C)−
3 (increase in activity F′s duration)=8days.
It is important for the contractor and subcontractors to re-examine the float of
every activity after the update. Float often changes with updates, since it is impacted
by past performance and changes implemented in the update.
Contractor-Created Float
When the general contractor or a subcontractor performs at a faster pace than planned,
more float may be added to the remainder of the schedule. For example, if an activity
finishes 2 days ahead of schedule, the result may be a float increase for some of the
succeeding activities. If the activity was critical, the result may be an earlier finish date
for the entire project. The author calls this type of float
contractor-created float
.
This situation poses some interesting questions: Does the contractor or subcontractor
who “created” this float own it? In other words, can he or she later “take back” this
float for a succeeding activity? Can the owner take it if the contract gives ownership
of the float to the owner? If the float was created by a subcontractor working on a
critical activity and resulted in an early finish for the entire schedule, who gets the
“bonus,” if any? Does it work both ways: If the subcontractor delayed work and this
delay resulted in a delay for the entire project, is the subcontractor responsible for any
liquidated damages? The answers to these questions depend mostly on the contract. In
many public projects, in which time is critical and the public's convenience is at stake,
the government adds both “carrots” and “sticks” in the contract. In the aftermath of
the Northridge earthquake, Caltrans (the California Department of Transportation)
used this policy heavily. Penhall, an Anaheim-based demolition contractor, signed a
contract that had a clause for a $75,000 bonus per day for each day finished ahead of
schedule and a similar amount in liquidated damages for finishing late (Rosta, 1994a;
Tulacz, 1994). C. C. Meyers received a $14.8 million bonus (the largest in the history
of public contracts) for finishing 74 days ahead of schedule. This amount was based on
a $200,000 per day bonus-liquidated damages clause in the contract (this case study
is discussed in more detail in Chapter 8). In some bonus-penalty contracts, a limit is
put on the bonus but not on the penalty. In 1995, Yonkers Contracting Co., Inc.,
Yonkers, New York, won a contract to modernize a four-lane, 2.5-mile stretch of the
Northern State Parkway across Long Island. The contract included a $20,000 penalty
for each day of delay after the deadline and a similar bonus amount for finishing ahead
of schedule, with a $2.4 million cap on the bonus. There was no cap on the penalty
(Cho, 1997). You may want to refer to the legal references listed in the “Construction
Scheduling Law” section of the Bibliography for more details.
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