890 likes | 1.06k Views
HISTORY OF SCHEDULING. When was the first recorded use of Scheduling Principles ?. HISTORY OF SCHEDULING. Early 1900’s – Henry Gantt uses a bar chart to schedule manufacturing processes – I&ME Application 1950’s – DuPont and Univac develop CPPS for Refinery network
E N D
HISTORY OF SCHEDULING When was the first recorded use of Scheduling Principles?
HISTORY OF SCHEDULING • Early 1900’s – Henry Gantt uses a bar chart to schedule manufacturing processes – I&ME Application • 1950’s – DuPont and Univac develop CPPS for Refinery network • 1950’s – Navy and Lockheed develop PERT for the Polaris missile project
HISTORY OF SCHEDULING • 1963 – AGC endorses CPM – CPM is a topic at the AGC annual convention • 1965 – CPM in Construction published • Early 1960’s – GSA and Corp of Engrs require use of CPM on big projects • 1970’s – Computer software for CPM becomes widely available – Fortran IV and Basic programming languages
HISTORY OF SCHEDULING • 1983 – Primavera Company founded • 1992 – Primavera buys SureTrak and integrates it with P3 (Primavera Project Planner) • 1998 – Microsoft Project introduced
CE 405 - SCHEDULING Primavera Scheduling Programs • SureTrak • Contractor • P6 – Primavera 6.0 (upgraded P3) • Prime Contract • Expedition – web-based • www.Primavera.com
CE 405 - SCHEDULING The challenge in Construction today is the integration of all of our software systems (estimating, accounting, scheduling, etc.) so they can be driven out of one common, shared data base. • You only want to input data onetime if possible
CE 405 - SCHEDULING Primavera will work with Oracle, SAP, and other proprietary construction software providers (HCSS, Timberline, etc.) to develop an integrated system – for a sizeable fee – that allows all of your software systems to work together.
CE 405 - SCHEDULING Review: What are the steps involved in Planning and Scheduling a Construction Project?
CE 405 - SCHEDULING Review – Scheduling Steps 1. Identify Activities 2. Estimate Activity Durations What do you do next?
CE 405 - SCHEDULING Review – Scheduling Steps 1. Identify Activities 2. Estimate Activity Durations What do you do next? 3. Figure out how all the Activities “fit together”
CE 405 - SCHEDULING Figuring out how all the Activities “fit together” – is often referred to as “sequencing” the Activities The other more common term that you will hear is “developing the Schedule Logic”
CE 405 - SCHEDULING Think of Scheduling as a triangle: • Identify Activities • Estimate Durations • Develop the Logic • You need all three pieces to develop a ProjectSchedule.
CE 405 - SCHEDULING Bar Charts add the Logic piece to the Scheduling process. • What Activities follow each other in sequence? • What Activities can be done simultaneously?
CE 405 - SCHEDULING What are the four types of Activity Relationships – How the various Activities may be related to each other?
CE 405 - SCHEDULING • Four Activity Relationships • Physical
CE 405 - SCHEDULING • Four Activity Relationships • Physical • Safety
CE 405 - SCHEDULING • Four Activity Relationships • Physical • Safety • Resource
CE 405 - SCHEDULING • Four Activity Relationships • Physical • Safety • Resource • Preferential • What are examples of each type?
ACTIVITY RELATIONSHIPS • Physical – Road base course material has to be placed before the asphalt/concrete wearing course can be placed. • Where one Activity has to be substantially completebefore the follow-on (Successor) Activity can start – logical progression.
ACTIVITY RELATIONSHIPS • Safety?
ACTIVITY RELATIONSHIPS • Safety – When placement of concrete requires the bucket to be swung over laborers digging in utilities – one Activity or the other will have to be deferred to maintain a Safe working environment. • Some Activities will be mutually exclusive due to Safety concerns
ACTIVITY RELATIONSHIPS • Safety – When you are working on a bridge over water, you have to obtain a lifeboat, and have it available to perform a rescue if necessary • It goes without saying that all Safety EquipmentMUST be onsite before activities dependent on that Safety Equipment can start
ACTIVITY RELATIONSHIPS • SAFETY IS JOB ONE • NEVER allow your Safety Standards to be lowered or compromised because you (or someone else) failed to plan for adequate/required safety measures far enough in advance.
ACTIVITY RELATIONSHIPS • SAFETY IS JOB ONE • You might get “lucky” and not have an accident the first few times – but ignoring Safety requirements will catch up with you – sooner or later
ACTIVITY RELATIONSHIPS • SAFETY IS JOB ONE • What is your response to someone who asks you to waive a safety requirement because they didn’t plan far enough in advance, and consequently don’t have the appropriate Safety equipment or materials?
ACTIVITY RELATIONSHIPS • SAFETY IS JOB ONE • What is your response to someone who asks you to waive a safety requirement? • “Failure on your part to plan sufficiently far enough in advance does not constitute an emergency on my part.”
ACTIVITY RELATIONSHIPS • SAFETY IS JOB ONE • What is the litmus test that you always want to subject yourself to when you think about not complying with a SafetyRequirement?
ACTIVITY RELATIONSHIPS • SAFETY IS JOB ONE • Do you want to be the one “knocking on the front door” who has to tell a wife/husband that their spouse was killed on your Job? • Always use this as the litmus test when someone asks you to ignore or disregard a Safety standard.
ACTIVITY RELATIONSHIPS 3. Examples of Resource Relationships?
ACTIVITY RELATIONSHIPS 3. Resource – If the Carpenter crewbuilding forms for a concrete driveway is the same crew scheduled to frame walls on the house – the Scheduler will have to decide which Activity will be performed first
ACTIVITY RELATIONSHIPS 3. Resource – If the Mechanical subcontractor needs to use the crane at the same time to install a chiller on the roof at the same time the steelworkers need it to place some steel beams elsewhere, the Scheduler will have to prioritize one Activity over the other.
ACTIVITY RELATIONSHIPS • Resource – Schedule Durations are based on the premise that once work starts on that Activity, it will continue until it is completed. • The reality is that crews will be frequently“pulled off” one Activity before it is completed to work on another more urgent Activity.
ACTIVITY RELATIONSHIPS • Resource– Schedule Updates have to show these “starts-and-stops” on interrupted or intermittent Activities. This can quickly become very complicated and very messy if you are going to accurately portray how the Job actually progressed.
ACTIVITY RELATIONSHIPS 4. Examples of Preferential Relationships?
ACTIVITY RELATIONSHIPS 4. Preferential– Some Contractors “prefer” to perform the landscaping sitework at the end of the Job, even though it could be performed earlier – this is a matter of choice and not logically constrained by other Activities
ACTIVITY RELATIONSHIPS • Preferential • You may prefer to not place concrete in the wintertime - nothing stops your from placing concrete then – it is just more difficult to do, and costs more to accomplish the work
ACTIVITY RELATIONSHIPS • Preferential • When you are “trying to save some time” on your Schedule (Schedule Compression), Preferential Relationships are the first Activities that you look at since they may be able to be done concurrently with other work
BAR CHARTS Bar Charts are the most widely used, and the most simple Scheduling format.
BAR CHARTS What is a Bar Chart?
BAR CHARTS What is a Bar Chart? A two dimensional (time) graph that shows when all the Activities on a Construction Project are planned to be accomplished. The Activities are listed in the left column, and horizontal bars show the time frame for each Activity.
BAR CHARTS To construct a basic Bar Chart, there are several considerations that have to be taken into account: • Bar Chart Layout • Time Unit • Workdays or Calendar Days • Showing Non-Continuous Work
BAR CHARTS Bar Chart Layout Although some Activities will follow each other chronologically, others may be done simultaneously. As the Scheduler – it will be up to you to decide in what order you will list(“sort”) the various Activities in the left column.
BAR CHARTS Time Units The Bar Chart Schedules for Large, Long-Duration, Complex Projects tend to become very extensive if the Scheduler uses a weekly time interval, but compressing it into a monthly time unit may not show the level of detail that you need.