Analysis of Construction Cost Optimality of Construction Project Working Implementation Materials

SUMMARY

Singgih Setyohadi, NIM 06206110052, Postgraduate Program of Brawijaya University, Examination Date of January 31, 2009, Analysis of Construction Cost Optimality of Construction Project Working Implementation Materials in Malang, Advisors: (I) Ir. Agus Suharyanto, M.Eng.,PhD., (II) Ir. Sugeng P. Budio, MS.

 

          The excess supply planning of cement and sand materials may emerge a risk of additional cost, additional cost maintenance and storing though it may guarantee the smoothness of construction project working implementation. The risk can be lessen by doing the planning of supply by calculating the amount and the time of economical order, ROP, supply cost and the total cost of materials supply. This research aims at calculating the amount of supply, ROP, and economical materials supply cost. It studies 6 contractors who are doing their construction project in Malang.

            This research employs a descriptive quantitative method. Data is collected in the form of the amount of need and the arrival of cement delivery (kg) and sand (m3) which is observed through the cement and sand supplies in every contractor. Data of price fare of loading and discharging of cement and sand is collected trough interview to logistic department in each contractor. The period of data collecting for each contractor is not similar which is 19 weeks, 22 weeks, 15 weeks, 23 weeks, 18 weeks, and 20 weeks, respectively. Then, data is analyzed by software DS for Windows. In addition, t-test is used to find the difference of supply, ROP, supply cost and total cost of contractor supply with EOQ.

            Findings show that there is a significant difference between the differences of the amount of cement supply in each contractor with the calculation result of EOQ. On the other hand, the frequency of order for each week is not effective. The difference of sand material supply between contractors who have the difference of supply cost of cement material is significant although the amount is small. The difference of contractor I is significant for 4.52% of cement and 1.2% of sand; the difference of contractor II is significant for 7.79% of cement and 1% of sand; the difference of contractor III is significant for 6.26% of cement and 1.2% of sand; the difference of contractor IV is significant for 34.39% of cement and 0.35% of sand; the difference of contractor V is significant for 13% of cement and 17% of sand; the difference of contractor VI is significant for 8.99% of cement and 0.4% of sand. Secondly, EOQ is more efficient of 7%. Thirdly, the total cost of contractor is considered equal to EOQ though there is 5% difference. Fourthly, EOQ is more efficient of 17.8%. Fifthly, the total amount of contractor is considered equal to EOQ although there is a small difference of 8%. It is suggested that the contractors should be able in predicting the cement and sand needs so that the construction project will be conducted as the schedule. At the end of the week, the evaluation of the cement and sand residue of the previous works as the consideration source of materials supply for the following week.