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ACH 216 Lecture 08 (Scheduling)
 

ACH 216 Lecture 08 (Scheduling)

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    ACH 216 Lecture 08 (Scheduling) ACH 216 Lecture 08 (Scheduling) Presentation Transcript

    • Project Management & Control Project Funding (LECTURE 7) Scheduling (LECTURE 8) Issues During the Construction Project (LECTURE 9) Materials Management and Quality Control (LECTURE 10)
    • Scheduling Definition and Purpose of Scheduling History Stages of Scheduling Preconstruction Construction Postconstruction Scheduling Methods Bar Chart Network Schedules
    • What is Scheduling?
      • Process of listing a number of duties or event in the sequence that they will occur
      • Properly schedule project tasks by:
        • listing the tasks,
        • organizing the tasks and
        • placing the tasks in sequential time relationships to each other.
      • Formulates the activities that must be accomplished to reach a goal or objective
    • What is Scheduling?
      • A schedule must accurately identify:
        • All tasks required to be completed on the project
        • Determine how long each will take
        • Place them in the correct, logical sequence
    • Why is Scheduling required?
      • Construction scheduling is a critical element to successful project management.
      • Along with building a project for less than the bid price, a project must be completed in less than anticipated time in order to make a profit.
      • Schedules establish the start, duration and completion date of the project or task
    • The History….
      • Formalized use of schedules has been in use since 1950’s
        • 1956: E.I. du Pont de Nemours Company used a UNIVAC computer and developed the Critical Path Method (CPM) schedule for a $10M chemical plant in Louisville, KY
        • 1957: U.S. Navy used a Performance Evaluation and Review Technique (PERT) network schedule to manage the development of the Polaris missile
      • Both types of schedules were used by NASA, Army Corp of Engineers, the Atomic Energy Commission, RCA, GE, the VA and GSA throughout the 1960’s
    • Stages of Scheduling
      • Scheduled start dates determine:
        • when goods and services need to be brought to the job site
        • when a work force needs to be mobilized
        • when equipment rentals begin
      • These dates are critical to the accurate pricing of the job
        • TIME = $$$$$$$$$$
      • Coordination of subcontractors/trades is critical
        • One day you can get them on site, the next you can’t
    • Stages of Scheduling
      • Delivery of material prompts storage and handling issues
        • Long lead-times could force material to be ordered and delivered early
        • But could also lead to storage problems
        • Possible lost, stealing or vandallization
      • Site capacity drives coordination for delivery and immediate usage
    • Stages of Scheduling
      • 3 Stages of Scheduling
        • Preconstruction
        • Construction (during execution)
        • Postconstruction
    • Stages of Scheduling Preconstruction
      • Allows owner to determine if project can be completed to his/her required contractual schedule
      • Owners must present schedule to banks to secure financing
        • Give prospective to financial institutions regarding payment of interest on loan and how long loan will be taken out for
      • Gives owner foresight to plan and coordinate properly the entire design and construction process-
        • creates a SUCCESSFUL PROJECT
    • Stages of Scheduling Preconstruction
      • Gives the Project Manager the opportunity to design and build the project “on paper” prior to actual construction
        • Allows all parties a visual of the process and make necessary provisions to properly coordinate all work
        • Project team can determine long lead items
        • May require project to be started before design is complete (fast-tracking); thus shortening delivery time for the project
    • Stages of Scheduling Construction
      • Schedule is absolutely essential for coordination of day-to-day activities
        • Executable tasks for construction
        • Material delivery
        • Submittal and shop drawings
        • Equipment use (rental costs)
      • Daily recording of events and executed tasks are added to the schedule to track progress and DELAYS
    • Stages of Scheduling Construction
      • DELAYS WILL HAPPEN!!!
        • Causes for delays
          • Weather
          • Equipment failures
          • Labor strikes
          • Design errors and omissions
          • Bad coordination of subcontractors
          • No-show of subcontractors
          • Owner associated delays (financial, informative and/or legal)
        • Project Manager must handle delays effectively and quickly
          • Must try to foresee possible delays as much as humanly possible
    • Stages of Scheduling Construction
      • Use of Critical Path Method (CPM) is used to record actual activities from a day-to-day basis.
        • Allows PM to record the progress graphically
        • Also helps anticipate problems that may occur in the future
        • May become essential in negotiation of change orders and delay claims
    • Stages of Scheduling Construction
      • Delay Claims
        • Contractor issues claim against owner for delay in schedule that results in loss of money
          • “ impact costs” or “consequential damages”
            • Additional expenses incurred by contractor as a consequence of a delay
            • results in owner failing to:
              • provide information
              • timely delivery of site
              • make timely decisions
              • provide owner-furnished materials/equipment
            • Contracts are written to allow for time extensions in these cases
    • Stages of Scheduling Construction
      • Delay Claims
        • Contractor issues claim against owner for delay in schedule that results in loss of money
          • “ impact costs” or “consequential damages”
            • A/E errors and omissions account for numerous contractor claims
              • Unreasonable delays in shop drawings and submittal review and approval
    • Stages of Scheduling Construction
      • Delay Claims
        • Contractor can also issue claim against subcontractors
          • If subcontractor delays in his/her own work, can produce a “domino effect” on all trades that follow
          • One trade depends on the work of another trade
    • Stages of Scheduling Postconstruction
      • When completion nears, typically the end-user becomes more involved in the construction process
        • Owner or tenants may begin to occupy building/facility before completion
          • Called “partial occupancy”
          • Must be closely coordinated and scheduled between base building contractor and tenant improvement contractor
        • Requires a period of testing and implementation of equipment and facility
    • Methods of Scheduling
      • The Schedule is a tool:
        • Used to manage, coordinate, control and report
        • Type of schedule depends on sophistication of project
      • Types (or Methods) of Schedules
        • Bar Charts
        • Network Schedules
        • Network-based Bar Chart Schedules
        • (most popular in construction industry)
    • Methods of Scheduling Bar Charts
      • A graphic diagram consisting of horizontal bars describing time period to perform work items
      • Also known as the Gantt Chart
      • Frequently used in planning stage to quickly examine overall timing for project
        • Work items are general and broad description
          • Work items are vertically listed along left boarder of chart
          • Time is represented horizontally along top section of chart
            • Time is expressed in weeks
            • Work is assigned start and end date
            • Time between two dates is period to perform work item
              • Time period becomes graphical bar on chart
    • Methods of Scheduling Bar Charts
    • Methods of Scheduling Bar Charts
      • ADVANTAGES
        • Preparation is simple
        • Easy to read & revise
        • Provides a quick, visual overview
        • Used to compare actual progress to planned
        • Best used in conjunction with network-based schedules
      • DISADVANTAGES
        • Cannot show detailed information
        • Cannot show interrelated items
        • Cannot define individual activity dependencies
        • No task information shown
        • Only good for simple projects
    • Methods of Scheduling Bar Charts
    • Methods of Scheduling Bar Charts
      • See notes for
      • PREPARATION GUIDELINES
      • for Bar Chart schedules
    • Methods of Scheduling Network Scheduling
      • Involves more detailed analysis of steps required to construct a project
      • Network schedule chart is a graphic schedule diagram indicating relationships between tasks.
      • Network analysis involves study of work tasks, not broad work items
      • Work tasks have a very limited scope
        • ie., installing lockset on doors for each floor
        • Since tasks are narrowly defined, interrelationships between them can be better understood
    • Methods of Scheduling Network Scheduling
      • Usual causes of construction delays occur when completing one task interferes with scheduled start of next related task
        • The second task’s precedent is the first task
      • Tasks are vertically placed in relationship to each other along horizontal time line.
    • Methods of Scheduling Network Scheduling
      • Each work item is called an ACTIVITY
        • Activities are given a duration
          • How long the activity will take in hours, days, weeks
        • Activities are connected into a network diagram
      • Completed network defines all activity interrelationships and durations
        • Considers what resources are available
        • Also assumptions about how project will be organized
      • THIS BECOMES THE “ROAD MAP” to the desired completed destination
    • Methods of Scheduling Network Scheduling
      • ADVANTAGES
        • Creates a definitive schedule of tasks and activities leaving little guessing for things to do next.
        • Very effective for managing projects required to meet specific completion date, since it permits determining of personnel needs to complete tasks.
        • Can be used as a method for determining efficiency of actual construction as related to estimated and theoretical construction activities.
      • DISADVANTAGES
        • Can oversimplify a non-professional’s understanding of construction process, thus making it useless to contractor and non-professional.
        • Does not necessarily stabilize construction personnel and equipment requirements. For stabilized personnel and equipment usage, labor planning must be included in preparation of network schedule to “smooth out” high and low periods of personnel and equipment usage.
    •  
    • Methods of Scheduling Network Scheduling
      • Two Major Styles of Network Scheduling
        • Critical Path Method (CPM)
        • Performance Evaluation and Review Technique (PERT)
    • Methods of Scheduling Network Scheduling: Critical Path Method
      • Uses an arrow diagram
        • One end of arrow indicates the start
        • Other end of arrow indicates completion
        • Length of arrow indicates duration of activity
      • In CPM, some activities precede others in a straight-line basis and cannot start until prior activity has been completed
        • Some activities can start before precedence is completed
        • Some activities are performed concurrently with others
    • Methods of Scheduling Network Scheduling: Critical Path Method
      • CPM schedules provide:
        • Concise info regarding planned sequences of construction
        • Means to predict with reasonable accuracy the time required for overall completion
          • Also time required to reach milestone events
        • Proposed calendar dates when activities will start and finish
        • Guide for shortening project’s completion time
        • Basis for scheduling subcontractors and material/equipment deliveries
        • Rapid evaluation of time requirements of alternative construction methods
        • Progress recording and reporting
        • Basis for evaluating the impact of delays and changes
    • Methods of Scheduling Network Scheduling: Critical Path Method
      • Key terms to know:
        • activity flow: sequence of work from one task to the other
        • order of activity or order of precedence : an indication of which work event or task precedes or follows the other
        • duration: time required to complete work task
        • nodes: graphic representation of specific tasks displayed as either a rectangle, hexagon or rounded box and usually contains a number identifying the task it represents
          • Could also include start and finish dates
          • Current software does not use NODES
        • early start: a date earlier that that initially anticipated for the start of an activity
          • But can be accomplished if its predecessor has been completed
    • Methods of Scheduling Network Scheduling: Critical Path Method
      • Key terms to know:
        • late start: a date indicating a start later than planned
          • But will still allow for on-time completion of task
        • early completion: completion of task prior to it’s initially scheduled date
        • late completion: completion of task later than originally scheduled
          • But having no effect on the overall scheduled completion date
        • float: contingency time allotted to a specific work task or series of tasks to compensate for unforeseen delays
    • Methods of Scheduling Network Scheduling: Critical Path Method
      • By planning, scheduling, monitoring and controlling tasks, a contractor can complete project in a very logical and efficient manner, which will produce a profit on the project.
    • Methods of Scheduling Network Scheduling: Network-Based Bar Charts
      • Combination of CPM and bar charts
        • Detailed durations and interrelationships between activities in a simple, easy to read bar graph
        • Most popular in construction industry
      • Software programs used:
        • Primavera Project Planner
        • Timberline
        • Microsoft Project
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    • NEXT CLASS LECTURE 9 Issues During the Construction Project