AON and AOA Network Diagrams

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Questions and Answers

What is an example of lag between two activities in an Activity-on-Node (AON) network?

Waiting for concrete to cure

What are common errors when drawing Activity-on-Node (AON) diagrams?

Not numbering nodes vertically and not putting the arrow on the side of the node.

What are the four main types of logical relationships between construction activities?

Finish-to-Start (FS), Start-to-Start (SS), Finish-to-Finish (FF), and Start-to-Finish (SF).

Describe the Finish-to-Start (FS) relationship between activities.

The following activity cannot start until the previous activity has been completely accomplished. Signup and view all the answers

What is the most common type of relationship between construction activities?

Finish-to-Start (FS) Signup and view all the answers

Describe the Start-to-Start (SS) relationship between activities.

A successor task cannot start until its predecessor task has also started. Signup and view all the answers

Describe the Finish-to-Finish (FF) relationship between activities.

A successor task cannot be completed until its predecessor task has been completed. Signup and view all the answers

Which relationship type abbreviation represents 'Activity A must finish for Activity B to start'?

FS Signup and view all the answers

Which relationship type abbreviation represents 'Activity A must start for Activity B to start'?

SS Signup and view all the answers

Which relationship type abbreviation represents 'Activity A must finish before Activity B can finish'?

FF Signup and view all the answers

What are the key guidelines for building an Activity-on-Node (AON) network diagram?

Use squares or rectangles for activities (nodes). Connect nodes only from the sides, not top or bottom. Do not combine relationship lines. Design the network flowing from left to right. Minimize line crossing for clarity. Start and finish with single, distinct nodes. Signup and view all the answers

What are the four scheduling dates typically calculated for each activity in both AON and AOA networks?

Early Start (ES), Late Start (LS), Early Finish (EF), and Late Finish (LF). Signup and view all the answers

What is the critical path in an AON or AOA network?

The longest sequence of activities through the network diagram. Signup and view all the answers

What are the different types of activity float?

Total Float (TF), Free Float (FF), Interfering Float (INTF), and Independent Float (INDF). Signup and view all the answers

Which types of activity float are most commonly used in construction scheduling?

Total Float and Free Float. Signup and view all the answers

Which type of activity float is rarely used in construction practice?

Independent Float (INDF) Signup and view all the answers

Define Total Float (TF).

The amount of time a task can be delayed without impacting the project's overall completion date. Signup and view all the answers

What are the formulas for calculating Total Float (TF)?

TF = LS - ES or TF = LF - EF Signup and view all the answers

What is the main difference between Total Float and Free Float?

Total Float focuses on the potential delay relative to the overall 'project finish date', whereas Free Float focuses on the potential delay relative to the 'Early Start (ES) date of any successor activity'. Signup and view all the answers

What does 'activity float' represent in project scheduling?

The amount of time an activity can be delayed without delaying the completion date of the project. Signup and view all the answers

What are the advantages of Activity-on-Node (AON) networks compared to Activity-on-Arrow (AOA) networks?

AON allows for more accurate scheduling (especially with complex relationships like SS, FF, SF) and does not require the use of dummy activities. AON often improves project management visualization and communication. Signup and view all the answers

What advantages do network diagrams (AON and AOA) offer compared to simple Bar Charts (Gantt Charts)?

Network diagrams provide a more detailed and visual representation of project dependencies (logical relationships) and scheduling calculations (like float and critical path). This allows for better planning, resource allocation, and risk management. Signup and view all the answers

Name a well-known computer software package used for project scheduling.

Primavera P6 Signup and view all the answers

Describe the basic format of an Activity-on-Node (AON) network.

Activities are represented by nodes (typically boxes or circles). Arrows connecting the nodes represent the logical relationships and dependencies between activities. Signup and view all the answers

What are key recommendations for building an Activity-on-Arrow (AOA) network diagram?

Represent the start and end points of activities with nodes (Events). Use arrows to represent the activities, labeled with activity identifiers and duration. Draw arrows to reflect precedence relationships accurately. Use dummy activities (dashed arrows) to show dependencies not representable by regular activity arrows. Number the nodes sequentially after the diagram is completed, ensuring terminal nodes have higher numbers than initial nodes. Signup and view all the answers

What is 'lag' in the context of project scheduling?

A delay or required waiting time imposed between the linked aspects (start or finish) of two related tasks. Signup and view all the answers

What are the primary outputs or purposes of performing forward pass calculations on a project network?

To determine the minimum duration of the project and the earliest time each activity can possibly start (Early Start - ES) and finish (Early Finish - EF). Signup and view all the answers

What is the consequence of a delay occurring in an activity on the critical path?

A delay in any critical path activity will delay the entire project's completion date. Signup and view all the answers

Provide an example of lag between two activities in an Activity-on-Node (AON) network.

Waiting for concrete to cure. Signup and view all the answers

What are the four main types of relationships between construction activities?

Finish-to-start (FS), start-to-start (SS), finish-to-finish (FF), start-to-finish (SF). Signup and view all the answers

Define the finish-to-start (FS) relationship in construction activities.

The successor activity cannot start until the predecessor activity has been completely accomplished. Signup and view all the answers

Define the start-to-start (SS) relationship in construction activities.

A successor task cannot start until its predecessor task has also started. Signup and view all the answers

Define the finish-to-finish (FF) relationship in construction activities.

A successor task cannot be completed until its predecessor task has been completed. Signup and view all the answers

Which relationship abbreviation corresponds to the statement: 'Activity A must finish for Activity B to start'?

FS Signup and view all the answers

Which relationship abbreviation corresponds to the statement: 'Activity A must start for Activity B to start'?

SS Signup and view all the answers

Which relationship abbreviation corresponds to the statement: 'Activity A must finish before Activity B can finish'?

FF Signup and view all the answers

What are the guidelines for constructing an Activity-on-Node (AON) network diagram?

Use squares or rectangles for nodes (activities); connect nodes only from the sides, not top or bottom; do not combine relationship lines; design the network flow from left to right; minimize line crossings; start and finish the network with a single node. Signup and view all the answers

What are the four key dates associated with each activity in construction network scheduling (AON and AOA)?

Early Start (ES), Late Start (LS), Early Finish (EF), Late Finish (LF). Signup and view all the answers

What is the critical path in a project network (AON or AOA)?

The longest sequence of activities through the network diagram. Signup and view all the answers

What are the different types of activity floats calculated in project scheduling?

Total float, free float, interfering float, independent float. Signup and view all the answers

Which two types of activity float are most commonly used in construction project management?

Total float and free float. Signup and view all the answers

Which type of activity float is rarely used in practical construction scheduling?

Independent float. Signup and view all the answers

How does total float differ from free float in terms of focus?

Total float focuses on the potential delay relative to the 'project finish date,' whereas free float focuses on the potential delay relative to the 'Early Start (ES) date of any successor activity.' Signup and view all the answers

In general terms, what is activity float?

The amount of time an activity can be delayed without delaying the completion date of the project. Signup and view all the answers

Compared to simple Bar Charts (Gantt Charts), what advantages do network diagrams like AON and AOA offer?

Network diagrams provide a more detailed and visual representation of project dependencies (precedence relationships) and the critical path, which Bar Charts often don't explicitly show. This allows for better planning, resource allocation, risk management, and understanding of how delays impact the overall schedule. Signup and view all the answers

Name a well-known computer software package used extensively for project scheduling.

Primavera P6. Signup and view all the answers

Describe the basic format of an Activity-on-Arrow (AOA) network.

In AOA networks, activities are represented by arrows, and the nodes (typically circles) at the beginning and end of the arrows represent events (the start or completion of activities). Signup and view all the answers

What are some key recommendations for constructing an Activity-on-Arrow (AOA) network diagram?

Represent the start and end of each activity with nodes (events); use arrows to represent the activities, labeling them with activity identifiers and durations; draw arrows to accurately reflect precedence relationships; use dummy activities (dashed arrows) where necessary to show dependencies without representing actual work; number the event nodes sequentially after the diagram logic is complete (typically left-to-right). Signup and view all the answers

What key information is determined through forward pass calculations in network analysis?

The minimum duration of the project and the earliest time each activity can start (Early Start - ES) and finish (Early Finish - EF). Signup and view all the answers

What is the direct consequence of a delay occurring in any activity on the critical path?

It will delay the completion date of the entire project. Signup and view all the answers

What are common errors made when constructing Activity-on-Node (AON) diagrams?

Not numbering nodes correctly (e.g., not vertically or sequentially) and not placing relationship arrows on the sides of the nodes. Signup and view all the answers

What are the four types of precedence relationships between construction activities?

Finish-to-Start (FS), Start-to-Start (SS), Finish-to-Finish (FF), and Start-to-Finish (SF). Signup and view all the answers

Describe the Finish-to-Start (FS) relationship between construction activities.

The successor activity cannot begin until the predecessor activity is fully completed. Signup and view all the answers

Describe the Start-to-Start (SS) relationship between construction activities.

A successor activity cannot begin until its predecessor activity has also started. Signup and view all the answers

Describe the Finish-to-Finish (FF) relationship between construction activities.

A successor activity cannot be completed until its predecessor activity has also been completed. Signup and view all the answers

Which type of relationship is described by: "Activity A must finish for Activity B to start"?

Finish-to-Start (FS). Signup and view all the answers

Which type of relationship is described by: "Activity A must start for Activity B to start"?

Start-to-Start (SS). Signup and view all the answers

Which type of relationship is described by: "Activity A must finish before Activity B can finish"?

Finish-to-Finish (FF). Signup and view all the answers

List the key guidelines for constructing an Activity-on-Node (AON) network diagram.

Use squares or rectangles for nodes (activities), connect nodes only from the sides, do not combine relationship lines, design the diagram flowing from left to right, minimize line crossings, and ensure the network starts and finishes with a single node. Signup and view all the answers

What are the four key schedule dates associated with each activity in AON and AOA networks?

Early Start (ES), Late Start (LS), Early Finish (EF), and Late Finish (LF). Signup and view all the answers

What is the critical path in an AON or AOA network diagram?

It is the sequence of activities that determines the longest path through the network, representing the minimum project duration. Signup and view all the answers

List the different types of activity float used in project scheduling.

Total Float, Free Float, Interfering Float, and Independent Float. Signup and view all the answers

Which type of activity float is rarely used in construction scheduling?

Independent Float. Signup and view all the answers

Explain the difference between Total Float and Free Float.

Total Float measures the delay possible without affecting the project finish date, whereas Free Float measures the delay possible without affecting the Early Start (ES) date of any successor activity. Signup and view all the answers

What is activity float in general terms?

It is the amount of time an activity can be delayed beyond its earliest start or earliest finish time without delaying the overall project completion date. Signup and view all the answers

Describe the basic format of an Activity-on-Node (AON) network diagram.

In AON diagrams, activities are represented by nodes (typically rectangles or circles), and the arrows connecting the nodes represent the logical dependencies or relationships between the activities. Signup and view all the answers

In project scheduling, what is lag?

Lag is a mandatory delay or waiting period inserted between the finish or start of a predecessor activity and the start or finish of its successor activity. Signup and view all the answers

What information is determined by performing forward pass calculations on a project network diagram?

Forward pass calculations determine the minimum overall project duration and the earliest possible start (ES) and finish (EF) times for each activity in the network. Signup and view all the answers

What is the consequence of a delay in any activity on the critical path?

A delay in any activity on the critical path will delay the completion date of the entire project. Signup and view all the answers

Flashcards

Lag Example

Waiting for concrete to cure between two activities in an AON network.

AON Diagram Errors

Common mistakes include incorrect vertical node numbering and misplaced arrows.