Critical Path Scheduling Under Resource Calendar Constraints

1. Article Presentation Critical Path Scheduling Under Resource Calendar Constraints From Journal of Const Engg. & Management By: Ming Lu, M.ASCE ; and Hoi-Ching Lam January, 2008 CEM-510 Presenter: M. Mazhar Anwaar Ul Haq Student ID: G200901410 Date: Oct 31, 2009

2. PRESENTATION OUTLINE • Objective & Triggers • Article Focus • CPM Basics Review • Resource Constrained CPM • Resource Limits & Resource Calendars • Total Float Determination • Case Studies • AON with FS Relationship • PDM with FS, SS, FF, SF Relationships • Writer's Conclusion • Presenter's Critique • Questions & Answers (Q/A) • Wrap Up

3. TRIGERS OBJECTIVE • To investigate the effect of resource limits and resource calendars in CPM scheduling using computer software P3. • Worldwide usage of CPM scheduling technique in construction Industry. • Primavera PP (P3) a powerful scheduling and planning tool yet has limitations. • Worldwide teaching of CPM as curriculum using P3 as software application.

4. Article Focus • CPM Basics Review • CPM use forward pass to determine the total project duration which is validated by the backward pass. • For ADM (AOA), FS relationship • Start Float = Finish Float • For PDM (AON), FS,SF, SS,FF relationships • Start Float may differ than Finish Float

5. Article Focus (Cont.) • Resource Constrained CPM • A schedule which is driven by the limited available resources and control the project activities progress. • Both manpower and machines constitute resources, unavailability of any one will bring the activity to a halt. • Resources allocation analysis is done due to resource limits and resource calendars.

6. Article Focus (Cont.) • Resource Limits & Resource Calendars

7. 2 Days Article Focus (Cont.) • Example to understand Resource Constraints • Activity : Floor Concreting • Duration: 6 Days • Resources : Concreting Crew Crain

8. Article Focus (Cont.) • Imposing Resource Calendars on Resource Loaded Schedule • An Interruption event due to resources limitation S : Start of Interruption F : Finish of Interruption When interruption is occurring at the start of an activity or before EST- Delay in EST When interruption is occurring between EST & EFT- Delay in EFT

9. Article Focus (Cont.) • Total Float Determination • P3 Resource leveling feature when coupled with “meeting” calendar type and “Interruptible” activity duration can be used to resolve the resource unavailability constraints. • Potential errors in the TF calculations under such conditions. • Can be resolved by using the flowchart.

10. CASE STUDIES • AON with FS (Case-1 using P3) • No of Activities : 9 • Activity Type : One (Labor) Interruption • Resource Calendar Type: Meeting • Max Resource Limit: 6 • Scenarios: Three • S1- No Constraints • S2- Resource Constraints • Resource Constrains + Activity interruptions

11. CASE STUDIES • PDM with FS, SS,FF,SF (Case-2 using P3) • No of Activities : 5 • Resource Type : Two (Labor & Crane) Interruptible • Resource Calendar Type: Meeting • Scenarios: Four • S1 -No Constraints • S2- Resource Constraints • S3- Resource Constrains + Calendar Labor (6Days) • S4- Resource Constrains + Calendar Labor (6Days) & Crane (3 days)

12. CASE STUDIES • PDM with FS, SS,FF,SF(Case-2 using P3)

13. WRITER’S CONCLUSION • P3 functionalities for CPM scheduling under resource limits and resource calendars constraints has assessed based on PDM network and result gave overstated total floats. • P3 Failed to satisfied the SF relationship under resource constraints. • In response to the limitation of P3 to calculate total float under resource constraints condition a new method based on forward pass analysis is proposed to accurately calculate TF. • Critical issues of resource constrained scheduling is covered in field of Construction Project Management, which could be useful for CPM software users and vendors to improve the methodology.

14. PRESENTER’S CRITIQUE • The writer has lay down the article plot from basics of CPM, (FP, BP, Network types, Float etc.) which is good for the bingers but may fail to influence the experienced readers. • The article is not well structured , since certain statements and paragraphs seem out of place and incoherent. • There is a confusion in the terminology, PDM with four dependencies types (FS, SF, SS, FF) is considered different than AON method, which are actually one and same thing. • Writer did a good effort in highlighting the use of CPM scheduling under resource constraints through computer application but limited his research to P3 only. Although writer did mention that the research results are equally applicable to other CPM softwares but this aspect is not demonstrated in the article. • P3 limitations under resource constrained scenarios are addressed and effort is made to rectify the imperfection of P3 for TF calculations through a manual procedure. The manual procedure demonstration is missing in the article.

15. QUESTIONS & ANSWERS Any Question Please !!!!!!!

16. WRAP UP Thank You for Listening Good By !!!!