5 critical path method Flashcards
What are critical activities?
activities that must be completed on time if the entire project is to be completed on time
What is the float?
the amount of time that an activity can be delayed without delaying the project completion date
What is the critical path?
The sequence of activities which represent the longest total time required to complete the project
What is a lag?
Delaying the following activity by an amount of time
What is a lead?
It means that an activity can be started earlier by a certain time period
What are the 3 steps of estimating activity duration?
1 find quantity of each item by doing a material take off from the drawings or from BoQ
2 find the resources required usually from experience
3 find the unit output of each resource- from
A experience or historical production records
B standards
C from work study - for repetitive processes
What is the earliest start/finish time?
The earliest time an activity can start/finish without affecting total project time or logic of the network
What are the benefits of knowing the total float?
can move around non-critical activities and avoid over-allocation of people or equipment and can use resource levelling
Why might an activity be delayed?
1 the planning was incorrect and unrealistic- based on historical data no applicable or manufacturers outputs wrong
2 project not controlled - wrong resources or not enough or not motivated
why might a non-critical activity become critical?
Many reasons might contribute to start times being affected: • Previous activities late • Resources not available or ready • Site not ready • Plans not complete • Design not complete • Permissions not ready Reasons why the duration might be affected: • Insufficient resources • Inadequate resources • Inadequate work areas • Low supply of materials, designs, instructions etc
whats an issue when the full network is pretty critical?
1 need to sure each activity starts on time which needs the activity before to end on time and have done all prep work
2 risk to client to mitigate risk by changing project logic or ensuring adequate resources
how much of a lag is there usually between design and construction?
5 weeks
What are issues with starting design and construction at the same time?
1 cost of design increase
2 final cost unknown before construction starts
3 design errors may not be checked before construction starts
4 construction sequence and timing to be altered leading to longer construction phase
5 contractor probs claim
6 risks for client
7 may have to re-negotiate contract
8 problems may result in project actually taking longer
