L6.2 planing&scheduling
- 1. EGNR 300 Project Management Planning & Scheduling -------------------------- ENGR 300 Dept. of Computer Science and Engineering University of Bridgeport, CT 06601
- 2. “Failing to plan is planning to fail” by J. Hinze, Construction Planning and Scheduling • Planning: – “what” is going to be done, “how”, “where”, by “whom”, and “when” – for effective monitoring and control of complex projects
- 3. “Its about time” by J. Hinze, Construction Planning and Scheduling • Scheduling: – “what” will be done, and “who” will be working • relative timing of tasks & time frames – a concise description of the plan
- 4. “Once you plan your work, you must work your plan” by J. Hinze, Construction Planning and Scheduling • Planning and Scheduling occurs: – AFTER you have decided how to do the work • “The first idea is not always the best idea.” • Requires discipline to “work the plan” – The act of development useful, – But need to monitor and track • only then, is a schedule an effective management tool • as-built schedules
- 5. The Work Break Down Structure (WBS) • An organizational tool for complex projects – A first step in creating a schedule – Useful for defining the Scope of Work • After decided how to do the work • Consists of: – Goal statement for project – Subdividing goal into smaller & smaller portions
- 6. WBS • Upper two or three levels – require only general knowledge – don’t get too detailed too quickly • The deeper you go, the more knowledge you need • Bottom level tasks: • simple enough to estimate durations • can assign crews • each task has a natural sequence relative to other tasks
- 7. Example WBS Warehouse WBS Site Boundaries Elevation Data Points Building Footprints Locate Buried Services Survey Soils Analysis Excavate Soil Backfill & Compact Site Preparation Foundation Structural Systems Finishing To construct a 5-unit warehouse for light industry Complex Could be used to define scope of work for surveyor sub-contract
- 8. Order of Task Execution - Scheduling • Bar Charts (Gantt Charts) – length of bar = task’s duration – commonly used, require little training – precedence relationships difficult to show • precedence = the sequencing relationship between tasks
- 9. Order of Task Execution - Scheduling • Network Diagrams – Critical Path Method (CPM) • w/in construction - most important – Program Evaluation and Review Technique (PERT) • like a generalized CPM • assumes that an activity’s duration cannot be precisely determined – takes most likely, optimistic, pessimistic estimates – computes an expected duration/activity and expected project duration
- 10. Critical Path Method (CPM) • Identifies those chains of activities (critical paths) that control how long a project will take. • Two variations: – Activity-on-Arrow (AOA) • activities are the arrows or lines – Activity on Node (AON) • also known as a Precedence Diagram • activities are nodes connected together by lines
- 11. Some CPM Terms • Float = the amount of time an activity can be delayed without delaying the project • Critical = activities with no float; these activities can not be delayed w/o extending project duration • Contingency = include a time allowance to account for time slippage & other delays • Slippage = difference between actual and scheduled progress
- 12. Computer Scheduling “Projects should be scheduled one byte at a time” by J. Hinze, Construction Planning and Scheduling
- 13. Creating a Computerized Schedule • Primavera P3, SureTrak, CA-SuperProject, MSProject • Uses CPM for calculating project duration • Offer Gantt and Precedence views – Gantt the default – Activities can be viewed in other forms: activity and resource calendars, spreadsheets • Useful for – updating and tracking – sorting, filtering, resource leveling
- 14. Creating a Computerized Schedule • Specify a base calendar – calendar days vs. working and non-working days – specialized activity and resource calendars • tasks that cannot be performed on specific days • days that resources are available – (otherwise assumed that resources are available at all times on every working day) • Specify the project start or finish date
- 15. Creating a Computerized Schedule • Input activities from the WBS – basic info needed: name, duration, predecessors, and successors – if relevant: resources utilized plus associated costs • Collapsing the schedule – consolidating subtasks within their summary tasks to view main project activities w/o cluttering the screen
- 16. Creating a Computerized Schedule • Expanding the schedule – showing sub tasks w/in respective summary tasks • Link lines – the line that connects the bars of linked tasks on the Gantt chart
- 17. Creating a Computerized Schedule • Linking – creating relationships between activities – finish-to-start, start-to-start, finish-to-finish, or start-to-finish – can include lag or lead times • Network loop – circular logic within a set of activities – all loops must be eliminated for computations to be made
- 18. Creating a Computerized Schedule • Progress bar – graphical representation of the % completion of an activity at a specific date – shown adjacent to, or within, the activity bar • Summary task – representing a general activity of construction – duration calculated from sub-tasks • Create a baseline schedule – original schedule created at the beginning • actual progress is compared to
- 19. Getting CPM w/MSProject • After input of schedule – choose Gantt view – use GanttChart Wizard to calculate CPM • Can filter and show only CPM – in drop-down menu: • project filtered for critical – to get back to full task list: • project filtered for all
- 20. Example - Roof Structure The following seven tasks are required for the erection of a building roof structure. Some of the tasks can be completed simultaneously; the overhang with sofit can be constructed while the deck is being installed. 1 Place & secure trusses, 2 days 2 Install roof deck, 7 days 3 Apply vapor barrier, 2 days 4 Apply roof cladding, 2 days 5 Construct roof overhang, 4 days 6 Install soffits, 4 days 7 Apply flashing, 6 days