PF3104/IPM4102 Lecture 4 Project Execution Scheduling - Activities PDF

PF3104/IPM4102 Project Execution Lecture 4: Project Execution Scheduling ‐ Activities Professor HWANG Bon‐Gang (Dr.) Dept. of the Built Environment, College of Design & Engineering  Today’s Topics Activity Definition/Type/Generation/Ordering/Duration (G9&10; H2&4; N7...

PF3104/IPM4102 Project Execution Lecture 4: Project Execution Scheduling ‐ Activities Professor HWANG Bon‐Gang (Dr.) Dept. of the Built Environment, College of Design & Engineering  Today’s Topics Activity Definition/Type/Generation/Ordering/Duration (G9&10; H2&4; N7) 2  Activity Definition & Type Generation Ordering Duration 3  Activity Definition "an activity is a time‐consuming definable task" is a specific task Example: Deck Installation ‐ How Many Activities? has a beginning and an end has a duration usually consumes resources is assignable (someone does it) is measurable in quantity or time has relationship with other activities Is associated with deliveries 4 Activity Types 1) Production 2) Procurement 3) Administrative 5  Activity Types 1) Production Activities:  Define the actual physical construction of the project  Example: Interior Walls  Erect Steel Stud Wall  Run Electric Conduit  Install Dry‐Wall  …  Example: Reinforced‐Concrete Walls  Erect forms  Install Rebars  Install M&E Wires & Pipes  Pour Concrete  … 6  Activity Types 1) Production Activities:  Activity location designation for multiple floors or phases  Activities sortable by floor and phase  Large enough to identify a meaningful quantity of work  Small enough to allow the scheduler to sort the activity by assigned trade and project location 7  Activity Types 2) Procurement (Purchasing) Activities:  Activities that need to occur to get all the materials, equipment, and subcontractors to the job site ‐> Procurement Schedule required (Examples: Order Tile, Approve Roofing Sample…)  Usually follow a typical procurement sequence  It is important to identify all submittal requirements  Allow adequate time frame for reviews and approvals  Special attention to long‐lead items Ordering & Typical Procurement Sequence 8  Activity Types 3) Administrative Activities:  Activities related to  Identification of requirements for inspections & permits by local officials or by regulatory agencies  Actual Inspection & permitting process  Multiple parties involved  Designers: Drawing specifications  Contractors: Inspection specification  Coordination / communication 9  *Milestone  Key event in the life of a project  Examples:  Excavation Start, Foundation Finish…  Plant Shutdown Start  1st Floor Office Finish  Phase I of New Expressway Construction Complete  Can be used to flag significant project accomplishments  Base of Performance Measure  Differences between Activities and Milestones?  Not consume Time or Resources 10  Activity Definition & Type Generation Ordering Duration 11  Activity Generation Work Breakdown Structure (WBS)  Systematic Means of Defining Activities  Breakdown a project into activities  Level of Detail: Frame vs. Frame Floor, Frame Load‐bearing walls, Frame roof, Frame interior partitions…  Who will use the schedule?  Manageable & Controllable? (HVAC for mechanical, electrical, & plumbing works?) 12  Activity Generation (Conceptual Schematic of Work Breakdown Structure) Source: Patrick, C. Construction Project Planning and Scheduling 13 Activity Generation (Work Breakdown Structure) Source: Patrick, C. Construction Project Planning and Scheduling 14  In‐Class Exercise WBS Frame Using the list of activities provided, Level 1 develop WBS for constructing a 3‐unit town house  3 levels in the WBS. Level 2  7 activities at the 2nd level  Each of the 7 activities at the 2nd level has 3~7 sub‐activities belonging to the 3rd level........ Level 3 15  List of Activities Note Activities Note Activities Access roads Inspection Build 1st & 2nd floor Inspection by contractor Build 1st & 2nd floor frame Install mechanical systems In‐Class Exercise Build a 3‐unit townhouse Insulation/sheetrock Build foundation Interior doors/trim carpentry Build porches & decks Interiorfinish Identify One Level 1 & Seven Level 2 Build roof system Building layout/engineering Landscaping Masonry Activities in the table Building layout/engineering Masonry Cabinetry Misc. sub‐systems Clear the site Paint & wall coverings Complete the WBS by assigning Closeout inspection Painting the rest of the actives at Level 3 Damp‐proofing Place & cure concrete Electrical systems Place exterior doors & windows Erect structure/frame Plumbing systems Excavate footings Prepare the site Exterior finish Punch list check Finish grade Roofing materials Floor coverings Rough‐in building location Formwork & reinforcing steel Siding Grade & drain Site layout & engineering Hardware/mechanical finish Strip forms HVAC systems 16 Work Breakdown Structure Solution Source: Patrick, C. Construction Project Planning and Scheduling 17  Activity Definition & Type Generation Ordering Duration 18  Activity Ordering Network Diagram ‐ Pictorial representation of the activities and the order in which they occur to complete the project in the most efficient manner There is a certain degree of flexibility about the order in which activities occur on a project There are several possible networks for a project Require agreement of project participants D F A D F A C Start C Finish B E G B E G Activity on Arrow Notation Activity on Precedent Notation 19  Activity Ordering Three Basic Questions to be asked 1) What activity must occur before this activity can be done?  Predecessor 2) What activity must follow this activity?  Successor 3) What activity can be accomplished at the same time that this activity is occurring? 20  Activity Ordering “Ordering activities is not necessarily as straightforward as it may seem on the surface” “Constraints”  Reduce flexibility  Lengthen project duration  Generally increase project cost  Confuse basic logic 21 Activity Ordering ‐ Constraints 1) Physical Constraints 2) Resource Constraints 3) Safety Constraints 4) Financial Constraints 5) Environmental Constraints 6) Contractual Constraints 7) Regulatory Constraints 22  Activity Ordering ‐ Constraints 1) Physical Constraints  Caused by Physical Construction Process Erect Forms before pouring concrete What’s the order of constructing reinforced‐ concrete walls?  Logic Constraints defined by “How” (construction methods) the process is to be carried out 23  Activity Ordering ‐ Constraints 2) Resource Constraints  Caused by Resource Availability Equipment, labor, material….. No of Crane vs. $$$ Amount of concrete placed in a single day (Batch plant capacity) *How Tower Cranes Build Themselves: https://www.youtube.com/watch?v=oSyC8pxJdeQ 24  Activity Ordering ‐ Constraints 3) Safety Constraints  Caused by Safety Requirements 2nd level floor drilling & 1st level ceiling electrical & mechanical Safety barrier installation before allowing work in the area Extremely hot or cold, or rainy days Lightening for night‐works 25  Activity Ordering ‐ Constraints 4) Financial Constraints  Caused by Money Independent Activities A($10M), B($10M) & C($10M) Payment Available 10M per month??? 5) Environmental Constraints  Caused by Mitigation Procedures Spawning season… Cow‐milk production??? 26  Activity Ordering ‐ Constraints 6) Contractual Constraints  Caused by Contract Phase by Phase (Hotel, Hospital, Condo….) Renovation, maintenance… 7) Regulatory Constraints  Caused by Regulations Environmental protection agency Land use restrictions Environmental constraints 27  Activity Ordering ‐ Constraints  Only physical constraints tend to be entered during the early development stage  However, other constraints should be identified as early as possible and reflected to the sequence of the activities “Reduce changes and their impacts on the project” 28  Activity Definition & Type Generation Ordering Duration 29  Activity Durations The duration of an activity is typically the estimated time:  that is required to complete it  that meets or exceeds quality standards  that provides for a safe work environment  Within budget  On schedule Time Unit  Depending on the project duration / nature of work  Hours / Days / Weeks / Months / Shifts  During Shut down? Large Number of Workers PLUS Shifts 24/7 30  Activity Durations Method used to determine duration of an activity varies depending on the activity type: 1) Production Activity 2) Procurement Activity 3) Administrative Activity 31  Activity Durations 1) Production Activity Duration  Steel erection / rough wiring / wood framing / Concreting / Etc.  Consult Subcontractors or In‐House Supervisors / Research past projects / Look at Data Books  Calculate based on Quantity and Productivity  A total of 10,000m3 concrete with productivity of 1,000m3 per day  ??? 32  Activity Durations 1) Production activity durations depend on: Job conditions (Floor vs. Ladder) Project nature (Grass‐roots vs. Renovation) Crew size (The more, the better?) Work schedule (Shift, 8/5, 10/4…) Weather (Seasons, multi‐year project…) 33  Activity Durations 2) Procurement Activity Duration:  Manufacture & delivery of structural steel components / curtainwalls / custom windows / special order cabinetry  Consult suppliers / vendors  Contract documents also have to be reviewed to allow for the time involved in the preparation of submittals, submittal reviews, & resubmittal if necessary 34  Production vs. Procurement Activity Calendars What do you mean by “in 6 weeks”?  When a window vendor states that the windows will arrive in 6weeks ‐> That usually means 42 calendar days  When a window installer says it will take 6weeks to install all the windows ‐> He generally means 30 working‐days (5 working days per week)  Concrete cures: on a 7‐day calendar  Concrete finishing : on a 5‐day calendar. 35  Activity Durations 3) Administrative Activity Duration  Time for securing permits and approvals  The permits are granted by government agencies  Use published information: submittal requirements, notification procedures, and time allowed for government action.  Consult owners, designers, or construction professionals who have worked on past projects in the area ‐> A good sense of the times and procedures involved in the administrative steps. 36  Activity Durations Productivity  Quantity / Workhour  Adjusted by regional or project‐specific factors “Guesstimates” Government, public agencies, experienced contractors  Large number of similar projects  Estimated & Actual durations  “Automated Algorithm” assigning an optimized duration to a specific activity 37  Factors Affecting Labor Productivity Congestion Sequencing Weather Supervision Plant Status Work Environment Information Equipment Tools Materials Rework Conversion INPUTS Technology OUTPUTS (WORKHOURS) (Work Method) (QUANTITIES) Size of Work Design Work Work to be Specification Done Components Content Features Scope 38 Productivity vs. Workhours 39 Productivity vs. Temperature & Humidity 10 – 21 °C 40 Productivity vs. Temperature & Humidity 21– 26 °C 41  Activity Durations Calculation Example 1:  What is the duration in days to install 6,000 ft2 of 3/8” drywall on walls, no finish included. Assume a crew of two carpenters. From Productivity Reference: Crew = 2 carpenters Daily output = 2,000 ft2  Crew size is the same as listed in the productivity reference Duration (days) = Quantity / Crew output ‐> 6,000 ft2 / 2,000 ft2 = 3 days 42  Activity Durations Calculation Example 2:  What is the duration of installing 15,360 ft2 of roof decks, cedar planks, 3” thick. Assume a crew of 3 carpenters working 8 work hours per day. From Productivity Reference: Crew = 2 carpenters / Daily output = 320 / Labor‐hours per ft2 = 0.05  Crew size varies from the crew listed in the reference Duration (days) = (Quantity X Labor‐hours per quantity) / (No.of Workhours per day X No. of workers in crew) ‐> (15,360 X 0.05) / (8 X 3) = 32 Days 43  Question In most construction projects, the total time for completion is equal the sum of the duration of all activities. A. True B. False 44  Activity Duration vs. Cost What if the activity duration is High much shorter than a typical duration? Cost ‐ How to make it shorter?  Overtime work Least Low Cost  Increase No. of Workers Short Duration Long  Increase No. of Equipment Cost Increase 45  Activity Duration vs. Cost What if the activity duration is High much longer than a typical duration? Cost ‐ How to make it longer?  Less than desirable crew size Least Low Cost  Inexperienced workers Short Long Duration  Decrease work‐hours per day  Overhead Cost Increase 46