Civil Notes Logo AboutCivil Logo Steps for Construction Scheduling, Construction Management, Arrow Diagrams, CPM Calculations, Node Diagrams and CPM Calculator.


Steps in Construction Scheduling

Advertisements

Planning  & Scheduling

Planning: Process of choosing the method and order of work

Scheduling: Process of determining the interrelationship of associated timings of operations.

Steps in Construction Scheduling

  • Splitting of the project into work activities
  • Determining logic relationships/interrelationships between activities.
  • Construction of Network Diagrams.
  • Assigning durations to work activities.
  • CPM Calculations resulting in start times, finish times and float calculations of activities.
  • Marking of critical Path
  • Construction of Bar Charts / Time phased diagrams.

Activity

  • An element of work performed during the course of a project. Or
    • An amount of work that can be identified so that we know what it involves and can recognize, when it starts and finishes.
  • An activity normally has an expected duration, an expected cost, and expected resource requirements

Network Diagrams

  • Any schematic display of the logical relationship of project activities.
  • Always drawn from left to right to reflect project chronology.
  • Usually a combination of arrows and nodes.

Mainly of two types:

  1. Arrow Diagram
  2. Node Diagram / Precedence Diagram

Arrow Diagrams

  • Activities shown by Arrows. Relationship between activities shown by nodes / events.
  • Length of arrows does not obey any scale.
  • Start-to-finish relationships.
  • Dummies.
  • Numbering of nodes / events.
  • Milestones

Possible Drafting Styles of Arrow DiagramsUse of a dummy Activity

Activity Durations

  • Activity duration is forecasted by any of the several means, including:
    1. Check Past Records.
    2. Check Standards and / or cost guides, if available.
    3. Ask the workers, who will do it
    4. make an educated guess
  • Any time units may be allotted to activity durations like days, hours, weeks, months, shifts, etc.
  • In CPM, a single duration is forecasted for an activity.
  • In PERT (Program Evaluation & Review Techniques), 3 durations are forecasted for an activity and mean taken by weighted average method. Then, Project’s Duration or any Event Completion Time is calculated by probability distribution.

CPM Calculations

  • Calculates the following for each activity

EST = Earliest Starting Time

EFT = Earliest Finishing Time

LST = Latest Starting Time

LFT = Latest Finishing Time

TF = Total Float

FF = Free Float

  • Total Float is Maximum time for which an activity can be delayed without delaying the project.
  • Free Float is maximum time for which an activity cane be delayed without delaying the start of proceeding activity.
  • Total Float = Free Float + Interfering Float

Critical Path

  • The path (or paths) in the network diagram, from start to finish, on which all the activities have zero total and free floats, is called Critical Path.
  • It is the longest path (or paths) from start to finish in a net work diagram.
  • It gives minimum normal time to complete a project.
  • It is usually marked by double lined arrows in a network diagram.


SINGLE SPAN BRIDGE PROJECT

    (ACTIVITY  DESCRIPTION)

Single Span Bridge Activity Project Description

Example Network Single Span Bridge Project Activities

Summary of Network Calculations

Node Diagrams

  • Activities shown by Nodes, relationship between Activities shown by arrows or links.
  • Easier to construct.
  • Generally no need of dummies. Instead dummies used only to give single start or finish.
  • CPM Calculations similar to Arrow diagrams.

Arrow Diagram & Precedence Diagram Correspondence

Sub Activities, Redundant Links Examples

Bar Chart

  • Gives Pictorial Representation of Activities.
  • Activities begin at EST and show their EFT, FF, TF, Durations, etc.
  • Arrows at the relative ends to show dependency.
  • Status Line Concept
  • Unable to show complete interdependency between Activities.
  • Time-scaled Network Diagrams show complete interdependency between Activities.
Relate Experiments

construction project quality management Construction Project Quality Management
Quality is an ever-changing state (i.e., what is considered quality today may not be good enough to be considered quality tomorrow)...

cost management techniques Cost Control Management Techniques
Involves determining what physical resources (people, equipment, materials etc) and what quantities of each should be used to perform project activities...

project scheduling and value engineering Project Control Schedule Value Engineering
The techniques for project control scheduling and control value engineering...

SJ Logo About Us | Site Map | Privacy Policy | Contact Us | © 2014 WebTechTix