CASE STUDY: DALVEY POINT STORM WATER UPGRADE PROJECT Summerline Contracting has just been awarded the Dalvey Point Storm Water Upgrade Project, a major and time-sensitive contract worth sev- eral million dollars. The Dalvey Point area is a retail district in a busy city center, drawing its name from the distinctive Dalvey Point Shop- ping Center at the intersection of Dalvey and Tanglin roads, labeled location 7 in the map below. Each of the three roads pictured must be closed to traffic at some point in the project, as Summerline Con- tracting installs storm water drainage culverts deep beneath street level to address recent problems with seasonal flooding in the basements of some Dalvey Point area buildings. Project Management 257 Dalvey Point Project Map 3 Stevens Drive Dalvey Road 5 Tanglin Road During road closure, Dalvey has agreed in its contract to provide the local vendors hardship payments of $10,000 a day for each weekday their road is closed, and $20,000 for each Saturday or Sunday. Vendors 1 and 4 are each entitled to payments when Stevens Drive is closed, while vendor 6 is entitled to those same payments when Tan- glin Road is closed. The remaining four vendors pictured in the map, including Dalvey Point Shopping Center, are entitled to payment from Summerline while Dalvey Road is closed. Each road must be closed while work is completed on three of the four tasks required there: Typical Four Stages of Activity Complete final survey and equipment staging Excavate Install culverts Close excavation and repave Road finished May close road and begin vendor hardship payments May open road and stop vendor hardship payments When to close or open a road is usually determined by the start of excavation and the finish of repaving on that road. But there is one important complication: while each road can be shut down separately, Tanglin Road must be closed the entire time Dalvey Road is closed, even if it is not being worked on. (If Tanglin Road were open but Dalvey Road closed, traffic on Tanglin Road would have no way to turn around at Dalvey Point.) Summerline has been experimenting with PERT and has employed its conceptual model to develop the time estimates shown in the Task Data table. Chapter 7 Task Data Task Abbrev. STVNS-1 Immediate Predecessor None Optimistic Time (days) 1 Most Likely Time (days) 2. Pessimistic Time (days) 3 2 4 6 STVNS-2 STVNS-3 STVNS-1 STVNS-2 1 2 3 STVNS-4 STVNS-3 1 2 3 DLVY-1 None 1 2 3 DLVY-2 Task Description Complete final survey and equipment staging for Stevens Drive Excavate Stevens Drive Install Stevens Drive culverts Close excavation and repave Stevens Drive Complete final survey and equipment staging for Dalvey Road Excavate Dalvey Road Install Dalvey Road culverts Close excavation and repave Dalvey Road Complete final survey and equipment staging for Tanglin Road Excavate Tanglin Road Install Tanglin Road culverts Close excavation and repave Tanglin Road 5 7 9 DLVY-1 DLVY-2 DLVY-3 5 7 9 DLVY-4 DLVY-3 2. 4 6 TNGN-1 None 1 2 3 1 3 11 TNGN-2 TNGN-3 INGN-1 INGN-2 2 4 12 TNGN-4 TNGN-3 1 3 11 While any work on any of the three roads can be scheduled simultaneously, Sum- merline would prefer that its own management team perform the final surveys and stag- ing arrangements for each road. As a result, it strongly prefers that the tasks abbreviated STVNS-1, DLVY-1, and TNGN-1 not overlap in time, so that the same team can complete all three. Questions 1. Using PERT analysis, how long do you estimate the Dalvey Point Storm Water Upgrade Project will require, and what is the probability that Summerline Contract- ing will be finished in that time? 2. Prepare a Gantt chart indicating your recommendations for the timings for each of the tasks, as well the road closures and reopenings. 3. On what day of the week would you recommend Summerline Contracting begin this project? Based on your recommendation and the expected task times from PERT, how much should Summerline budget for vendor hardship payments