© Construction Management Association of America. Do Not Duplicate or Reproduce. Standards of Practice Course CPM Scheduling Lab

© Construction Management Association of America. Do Not Duplicate or Reproduce. Activity Notation Use for Manual Calculation Early Start Late Start Early Finish Late Finish Duration Activity ID ESEF LSLF ID D FFTF Free FloatTotal Float April, 2010

© Construction Management Association of America. Do Not Duplicate or Reproduce. September, D A B C 4 00 FS  EF = ES + D - 1  ES = EF P + 1  LF = LS S - 1  LS = LF - D + 1  TF = LF - EF  FF = ES S - EF - 1 LF ESEF LS ID D FFTF Notation: Subscripts: S = Successor P = Predecessor Sample April, 2010

© Construction Management Association of America. Do Not Duplicate or Reproduce. September, 2006 CMAA Formulas for Calculation for Finish-to-Start Activities ES = EFP + 1 LS = LF - D + 1 TF = LF - EF EF = ES + D – 1 LF = LSS – 1 FF = ESS - EF - 1 April, 2010

© Construction Management Association of America. Do Not Duplicate or Reproduce. September, 2006 CMAA Calculation Tips 1.Start by taking note of the relationships. Notice which are not finish-start, or which ones are finish-start but with a lag. (Formulas don’t apply to Start-to-Start relationships or Finish-to-Finish relationships.) 2.Begin calculating on the first activity on the left side. 3.In CMAA’s examples, the first activity begins on Day One. Not Day Zero. 4.Work towards the right, in an up and down motion, in strips (this is to avoid unnecessary iterations). April, 2010

© Construction Management Association of America. Do Not Duplicate or Reproduce. September, 2006 CMAA Calculation Tips 5.When working with a lag greater than 0, first calculate the link as if it had no lag. Then add the lag time. 6.When an activity has multiple predecessors, each predecessor must be evaluated in turn to determine the correct early start date for the successor. During the Forward pass, the greater # (latest date) overrides. 7.The same concept holds true during the backward pass. For activities which have multiple successors, each successor must be evaluated to determine the correct late finish date for the preceding activity. During the backward pass, the lesser # (earlier date) overrides. 8.The last activity has no successor, so the late date formulas don’t apply. Assume for the last activity, EF = LF = END. April, 2010

© Construction Management Association of America. Do Not Duplicate or Reproduce. September, 2006 D 10 13A 3 4B 1 C 4 FS  EF = ES + D - 1  ES = EF P + 1  LF = LS S - 1  LS = LF - D + 1  TF = LF - EF  FF = ES S - EF - 1 LF ESEF LS ID D FFTF Notation: Subscripts: S = Successor P = Predecessor Exercise #1 April, 2010

© Construction Management Association of America. Do Not Duplicate or Reproduce. September, 2006 PART 1: Calculate a Baseline Schedule The AON logical network of a baseline schedule for a construction project is as shown in Exercise #2. Assume that for the last activity EF=LF=end of project. Required: Answer all questions on network diagram only 1.Calculate the ES, EF, LS, LF, and TF for each activity. 2.What is the free float (FF) for activity E? 3.What is the free float (FF) for activity F? Explain the difference in days between the FF and the TF for activity F. Exercise #2, Part 1 April, 2010

© Construction Management Association of America. Do Not Duplicate or Reproduce. September, 2006 A 10 D 5 F G H 5 E 5 B C Exercise #2, Part 1 All relationships finish-start unless noted. FS + 2 FS - 2 LF ESEF LS ID D FFTF Notation: SS + 5 April, 2010

© Construction Management Association of America. Do Not Duplicate or Reproduce. September, 2006 Exercise #2, Forward Path A B C D E F G H SS + 5 FS + 2 FS - 2 April, 2010

© Construction Management Association of America. Do Not Duplicate or Reproduce. September, 2006 Exercise #2, Backward Path A B C D E F G H SS + 5 FS + 2 FS - 2 April, 2010

© Construction Management Association of America. Do Not Duplicate or Reproduce. September, 2006 Exercise #2, Part 2 PART 2: Calculating Progress on the Schedule At the end of the day on day 15, the following progress information was available: 1.Activity A started 2 days late, and was completed on time. 2.Activity B started on time, and made progress as follows. a.Completed work in place = 500 sq ft b.Remaining work quantity = 500 sq ft April, 2010

© Construction Management Association of America. Do Not Duplicate or Reproduce. September, 2006 Exercise #2, Part 2 PART 2, Continued:  Activity D started on day 14. Remaining duration required for completion is estimated to be 2 days.  The original duration for Activity E changed from 5 days to 20 days. April, 2010

© Construction Management Association of America. Do Not Duplicate or Reproduce. September, 2006 Exercise #2, Part 2 PART 2, Continued: Required: Answer all questions on network diagram only Based on the progress information available at end of day 15, Q1. Calculate actual start and finish dates for all activities in progress. Q2. Calculate the ES, EF, LS, LF, and TF for all other activities. Identify the critical Path. April, 2010

© Construction Management Association of America. Do Not Duplicate or Reproduce. September, 2006 Exercise #2, Part 2 All relationships finish-start unless noted. A 10 D 5 F B SS + 5 FS + 2 FS - 2 LF ESEF LS ID D Notation: ASAF Actual Start Actual Duration Dur = RD if AD>0 Dur = RD if AD=0 (activity has not started) AD Actual Finish FFTF G 10 H 5 E 20 C 10 April, 2010

© Construction Management Association of America. Do Not Duplicate or Reproduce. September, 2006 Exercise #2, Forward Path A B C D E F G H FS + 2 SS + 5 FS - 2 Data Date – Day 16 April, 2010

© Construction Management Association of America. Do Not Duplicate or Reproduce. September, 2006 Exercise #2, Backward Path A B C D E F G H FS + 2 SS + 5 FS - 2 Data Date – Day 16 April, 2010