Optimization Study of Cost and Duration of Project Implementation Case Study: Spillway Construction of Bendo Dam Project

Good construction planning is one of the requirements for successful construction. This spillway construction with contract value of IDR99,939,304,966, - was under-schedule so that would affect the rest of the construction costs and duration. Then this study will discuss the optimization of rest costs and duration of this spillway construction. The solution in this study uses trial and error with CPM (Critical Path Method) and will get optimal costs and duration for the rest construction. The rest duration for the initial plan for construction of spillway is 192 days (9 months) with the rest contract cost of IDR46,593,769,076.80. Then control the time and cost of the remaining work using crashing with the method of adding labor and overtime work. A trial and error I result is IDR47,613,769,076.80 and IDR47,260,089,076.80 the efficiency duration is 6 months. Furthermore, trial and error 2 resulted in IDR47,721,769,076.80 and IDR 47,272,969,076.80 with a completion duration in 7 months, next trial and error 3 resulted IDR 46,621,669,076.80 and IDR 46,610,389,076.80 with 8.5 months. From the calculations and graphs of the three trials and errors get the conclusion for optimum cost results are IDR47,760,000,000,- with additional labor and IDR47,300,000,000,- with overtime work methods and the optimum duration is 138 days.