REKAYASA BIAYA KONSTRUKSI Dr. Ir. Budi Susetyo, MT Fakultas TEKNIK Program Studi S2 SIPIL MK 1
Rekayasa Biaya Konstruksi 1. Pengantar rekayasa biaya konstruksi 2. Estimasi biaya tahap konseptual dan detail 3. Biaya dan kontrak konstruksi 4. Ragam kontrak konstruksi 5. Pengendalian biaya 6. Pengendalian biaya konstruksi 7. Review UTS 1. Perhitungan biaya berbasis kegiatan (activity based costing) 2. Contoh perhitungan 3. Komponen biaya konstruksi 4. Contoh perhitungan 5. Pengendalian, monitoring dan akunting biaya 6. Contoh perhitungan 7. Review UAS 2
Estimasi Biaya Tahap Konseptual Hingga Detail 3
Tahapan Perencanaan Biaya Proyek Tahapan perencanaan biaya proyek (project cost estimates) yakni: 1. Tahap konseptual, atau perhitungan kasar (rough estimates) 2. Tahap semi detail (intermediate estimates) 3. Tahap detail (detail estimates) Rencana Anggaran Biaya (RAB) proyek yang telah dirinci peritem pekerjaan dengan mencantumkan rincian volume pekerjaan dan harga satuan merupakan produk perencanaan biaya tahap detail. 4
Cost Estimates Strategy In order to achieve accurate estimates in Project Management, cost estimating strategy is a must. This cost estimating strategy is developed based on a three-step process. Rough initial Estimates The Initial Rough Estimate is developed during the Initiating Phase and is based on the information provided in the high-level scope along with information from previous projects the project manager has been involved with or from similar projects they have heard about. This Initial Rough Estimate will be presented as a part of the Concept Proposal. Intermediate Estimates During the Planning Phase, the project requirements will be developed by the analyst and the project manager for the customer s review and approval and will further clarify and define the project estimates. More details are provided to the project team to allow them to help the project manager with project estimates. A detailed project schedule is created by the project manager to provide duration and effort for each task, the assignment of resources for each task, and a complete and detailed cost estimate of the project effort. Final Detailed Project Estimate The detailed project designs are created allowing the project manager to refine some of the project tasks and add the estimation of costs such as hardware, software, and items such as test equipment or additional space for the project team. At this point, the initial estimates created for the Concept Proposal can be updated or replaced to reconcile the more accurate total project cost information. The new estimate is communicated to the project stakeholder. 5
Basic Function Cost Estimates 1. Design Estimates For the owner or its designated design professionals, the types of cost estimates encountered run parallel with the planning and design as follows: * Screening estimates (or order of magnitude estimates) * Preliminary estimates (or conceptual estimates) * Detailed estimates (or definitive estimates) * Engineer s estimates based on plans and specifications For each of these different estimates, the amount of design information available typically increases. 2. Bid Estimates For the contractor, a bid estimate submitted to the owner either for competitive bidding or negotiation consists of direct construction cost including field supervision, plus a markup to cover general overhead and profits. The direct cost of construction for bid estimates is usually derived from a combination of the following approaches. * Subcontractor quotations * Quantity takeoffs * Construction procedures. 3. Control Estimates For monitoring the project during construction, a control estimate is derived from available information to establish: * Budget estimate for financing * Budgeted cost after contracting but prior to construction * Estimated cost to completion during the progress of construction.. 6
Skema Tahapan Perencanaan Biaya Proyek Tahapan Perencanaan Biaya Proyek (Cost Estimates) Konseptual Semi-Detail Detail Order Of Parametric End Index Building Detail/Unit Cost Magnitude Product System (RAB) 7
Order of magnitude Perhitungan biaya yang diperkirakan melalui besaran proyek Misal. Berapa biaya bangunan rumah tinggal 250 m2 Bila diketahui biaya bangunan rumah tinggal per-m2 adalah Rp. 3jt. Maka biaya bangunan adalah 250x3=Rp.750 jt. Parametric Perhitungan biaya didasarkan atas parameternya atau ciri komponennya. Misal. Berapa biaya bangunan rukan tipe menengah 200m2 Bila diketahui biaya bangunan rukan tipe menegah per-m2 adalah Rp. 4jt. Maka biaya bangunan adalah 200x4=Rp.800 jt End Product Perhitungan biaya didasarkan melalui produk akhirnya Misal. Berapa biaya bangunan hotel bintang 3-100 kamar Bila diketahui biaya bangunan hotel bintang 3-per kamar adalah Rp. 75jt. Maka biaya bangunan adalah 100x75=Rp.7,5 milyar 8
Index Perhitungan biaya didasarkan pada index perbandingan. Misal. Index biaya bangunan di Jakarta : Jogja = 1 : 0.75 Berapa biaya bangunan rumah tinggal di Jogja 100 m2 Bila diketahui biaya bangunan rumah tinggal per-m2 Jakarta adalah Rp. 3jt. Maka biaya bangunan adalah 100x3x0.75=Rp.225 jt. di Building System Perhitungan biaya semi detail didasarkan pada sistem bangunan. Misal. Biaya bangunan rumah tinggal 1 lantai tipe menengah 100 m2? - Pondasi bt.kali lajur-30m3 @800rb=Rp. 24jt - Dinding bata, plester aci, cat-600m2 @100rb=Rp. 60jt - Atap, rangka alumunium genteng keramik, 110m2 @ 200rb=Rp.22jt. - Pintu dan jendela 20 unit rata2@rp.2jt=rp. 40 jt - Utilitas, lumpsum Rp. 20jt. -Total = 24+60+22+40+20 = Rp. 166jt.. 9
Komponen Biaya Proyek Biaya Proyek Biaya Langsung (Direct Cost) BiayaTak-langsung (Indirect Cost) Material Pekerja Alat Subkon. Adm proyek Fas. Smntr Profit 10
Daftar Pustaka Sugeng Djoyowirono, 2003, Manajemen Konstruksi, Penerbit UGM Hendrickson, C., 1989, Project Management for Construction. Fundamental Concepts for Owners, Engineer, Architects, and Builders. Singapore, Prentice Hall. Bacaan Sejenis 11