BCM Construction Scheduling and Planning 2 — Questions and Answers
Question 1: The Program Evaluation and Review Technique (PERT) differs from CPM primarily because PERT:
- Does not use a network diagram
- Uses three time estimates to account for schedule uncertainty (Correct answer)
- Only works for repetitive construction tasks
- Requires resource loading for every activity
Correct answer: Uses three time estimates to account for schedule uncertainty
PERT uses optimistic, most likely, and pessimistic durations to calculate a weighted average activity duration, accounting for uncertainty in scheduling.
Question 2: In PERT analysis, the expected duration (te) of an activity is calculated using the formula:
- te = (O + M + P) / 3
- te = (O + 4M + P) / 6 (Correct answer)
- te = (O + 2M + P) / 4
- te = (M + P) / 2
Correct answer: te = (O + 4M + P) / 6
The PERT formula te = (O + 4M + P) / 6 weights the most likely estimate four times more than the optimistic or pessimistic estimates.
Question 3: Which scheduling technique is best suited for highly repetitive construction operations such as high-rise building construction?
- CPM
- PERT
- Line of Balance (LOB) (Correct answer)
- Gantt Chart
Correct answer: Line of Balance (LOB)
Line of Balance (LOB), also called Linear Scheduling Method, is ideal for repetitive work because it shows the rate of production and crew continuity on a time-location diagram.
Question 4: Schedule compression through 'Crashing' involves:
- Removing non-critical activities from the schedule
- Adding resources to critical path activities to shorten their duration at additional cost (Correct answer)
- Performing activities in parallel that were originally sequential
- Reducing project scope to meet deadlines
Correct answer: Adding resources to critical path activities to shorten their duration at additional cost
Crashing shortens the project schedule by adding resources (overtime, additional crews) to critical path activities, which increases direct costs.
Question 5: Fast-tracking as a schedule compression technique involves:
- Hiring faster subcontractors
- Adding more workers to critical activities
- Overlapping phases or activities that were originally planned in sequence (Correct answer)
- Using prefabricated materials to reduce installation time
Correct answer: Overlapping phases or activities that were originally planned in sequence
Fast-tracking overlaps activities (e.g., starting construction before design is complete) to compress the schedule, which increases risk of rework.
Question 6: A contractor is updating a construction schedule and notices the project has a negative float. This means the project is:
- Ahead of schedule
- On schedule
- Behind schedule and the planned completion date cannot be met (Correct answer)
- Using too many resources
Correct answer: Behind schedule and the planned completion date cannot be met
Negative float indicates the project is behind schedule — the calculated completion date exceeds the required completion date, requiring schedule recovery action.
Question 7: What is a 'Look-Ahead Schedule' commonly used for in construction project management?
- Long-range 5-year planning for a construction firm
- A 3-to-6-week short-term schedule used to coordinate upcoming work and identify constraints (Correct answer)
- The baseline schedule submitted at project start
- A schedule used exclusively for procurement of long-lead materials
Correct answer: A 3-to-6-week short-term schedule used to coordinate upcoming work and identify constraints
Look-ahead schedules (typically 3–6 weeks) help foremen and superintendents identify near-term work constraints such as material deliveries, submittals, and crew availability.
BCM Construction Scheduling and Planning 2
The Program Evaluation and Review Technique (PERT) differs from CPM primarily because PERT: