Value Engineering Approach for Construction Materials Selection of Irrigation Drainage

In this globalization era, many alternative choices of construction materials. The limited funds available make engineers have to think creatively to choose materials used in order to obtain the cost as efficiently as possible. There are many ways to do the cost efficiency of the project, one of them by doing value engineering . The construction design selection is very important to do because it can show the project quality, as well as produce the development with an efficient and optimal cost. The value engineering approach in the construction field is an organized and creative approach aimed at identifying unnecessary costs. These unnecessary costs are costs that do not provide quality or usability/functionality. The value engineering application is to construct projects has considerable potential savings from the project budget. This study aims to obtain cost savings made during the design phase and irrigation drainage project implementation. The scope of the study in the present study is the wall project on the DAS irrigation drainage improvement at Cengcengan River in Sukawati, Gianyar. This analysis uses the steps of value engineering plan, i.e., information, creative, analysis, development, and recommendation steps. Whereas, the criteria used to evaluate the components/systems included aspects of cost, quality, implementation time, methods, mobilization, availability, and aesthetics. In this study, four alternatives will be analyzed, i.e., alternative one using the river stone, alternative two conventional concrete K225, alternative three cycloof concrete and alternative four precast L shape. Regarding the analysis that has been conducted alternative four is the best alternative by using precast L shape which is used in irrigation drainage project using zero-one method. The cost savings obtained after replacing the stone masonry with precast L shape 20 years old is IDR. 23,754,327,910 with time savings of precast L shaped mounting work for 490 days


Introduction
The construction project is a series of interrelated activities to achieve a specific purpose (building/construction) within a certain time, cost and quality. Construction projects always require resources, i.e., human, materials, machines, methods, money, information, and time. In a construction project, there are three important things included time, cost and quality (Kerzner, 2006). One of the construction project activities is the irrigation drainage construction.
In this globalization era, many alternative choices for construction materials. The limited funds available make engineers have to think creatively to choose materials used to obtain the effective cost as possible. There are many ways to do the cost efficiency of the project, one of them by doing value engineering (Soeharto, 2001). Value Engineering is a systematic approach to obtain optimal results of any costs incurred in a creative effort event to analyze functions by removing or modifying unnecessary price increases in the process of financing the construction, operation or execution, maintenance, tools replacement, and others (Dell' Isola, 1974). Value engineering analysis method has advantages a systematic effort, neat, and organized approach in analyzing the subject matter value to the function or its usefulness but still consistent to the need for appearance, realities, quality, and the project maintenance.
Value engineering approaches are conducted to find alternatives or ideas aimed at generating better or lower costs than previously planned prices with functional and work quality constraints. This ensures that a responsible work outcome can be performed. This value engineering approach is carried out on irrigation drainage, wherein the physical construction of the old-fashioned irrigation, i.e., with river stone has many weaknesses. Therefore, alternative construction materials are sought in researching cost-saving opportunities without compromising overall construction performance, which would benefit all parties involved.

Research question
Based on the above background then it can be formulated some problems included: a) What is the best material alternative to replace the initial design of the irrigation drainage project? b) How much cost savings and time after the analysis with value engineering method?

Aims
The aims are to be achieved in the present research as follows: a) To find the best material alternative to replace the initial design of the irrigation drainage project b) To know cost savings and time after the analysis with value engineering method

Research significance
The research significance in the present study included: a) Overview the alternative materials that can be used in the application of value engineering to plate components in accordance with the value engineering criteria that must be effective and efficient.

Research Methods
The method is chosen in conducting the research is a descriptive evaluative. The research is intended, i.e., research that is conducted on an object systematically to get the facts and the object nature under study. Types and data sources Data is needed for this research included: a) Primary data Primary data is data obtained through direct observation in the field. It is obtained through interviews with respondents (suppliers) in the form of material price data, productivity. b) Secondary data Secondary data is data obtained by citing existing data through resource persons in the project. Data is in the form of project viewing, cost-saving plan and work plan and terms. Research procedure a) Information. At this stage, the building identification will be in value engineering. It contains general information, design criteria, and functions of the project item section to be analyzed. b) Creative. A search for alternatives will be used to replace the work items system that has been planned.
Unlike the alternatives can be made to substances/materials as well as designs rather than lower structural work items that will be value engineering. c) Analysis. Calculates a value/work item cost with the offered design alternatives. In calculating the cost can be reviewed regarding substances/materials, labor, time, and work items dimensions. In this stage, convey the contents by using the zero-one method. d) Recommendation. Provide recommendations for what is conducted in the previous stage, which can be either evaluation or potential value of the highest/greatest savings then summarized into one into a table.

Results and Analysis a) Information Stage
Project information data will be analyzed by value engineering:

Cost Model
The cost model is a part of work that is grouped according to each project element. It can be seen in the following figure 1.

b) Functional Analysis
Functional analysis is the main basis in value engineering. It distinguishes value engineering from other cost-saving techniques. This analysis assists the value engineering team in determining the lowest cost required to perform key functions and support functions and identify costs that can be reduced or eliminated without affecting performance or product constraints. The product/building function is thoroughly determined first before determining its elements function.

c) Creative Stage
In this stage, alternative ideas for drainage irrigation project began to emerge as a comparison of existing designs. Regarding the emergence of this alternative design is expected to create new design opportunities that can minimize the price. The alternative is conducted by making changes in the type of materials that will be expected to have a significant effect project on the price. On the project, the river stone installation is raised four alternatives included: 1) Alternative 1 using the river stone (existing).

d) Analysis Stage
The prior assessment process is conducted, it is necessary to prepare or give weight for each criterion. The order in ranking is sorted based on the questionnaire analysis results conducted. The ranking result is in the following table on a temporary weighting assessment. 1) Assessment using zero-one method At this stage, an assessment towards each alternative based on previously weighted criteria by using the zero-one method to obtain the index value of each alternative. Then, in determining the alternative assessment, it is necessary to arrange alternative preferences to make the assessment has a clear reference.  I  II  III  IV  Total  Index  I  X  1  1  1  3  ½  II  0  X  0  1  Zero-one assessment towards aesthetic/appearance function. (G)   Alternative  I  II  III  IV  Total  Index  I  X  1  1  0  2 2) Final assessment of alternative and existing (weighting) The weights and indices are known. Then, the next process is to perform the analysis using an evaluation matrix. Wherein, the matrix analysis multiplication is conducted between the weights of each criterion with each alternative assessment index that has been obtained. Then, each alternative summation can know which alternative has the highest value.
Based on the analysis results of evaluation matrix in Table 4, it can be seen that the alternative IV is using precast L shape mastering the highest total weight superiority is 32.73%. The weight value is obtained based on quality criteria, implementation time, implementation method, mobilization, material availability, and aesthetics/appearance.

e) Development Stage
The development phase is closely related to Life Cycle Costing, including the initial cost, maintenance cost, and disposition cost (residual value).

f) Recommended Stage
This stage is the final stage in doing value engineering that aims to provide recommendations for research that has been previously conducted. Before giving recommendations, as for the details of implementation cost and time of each alternative can be seen as follows. From the previous analysis using the zero-one method, it is recommended the best alternative for irrigation drainage project using precast L shape based on the following considerations: -Efficiency implementation time -Quality guaranteed -Material is easy to obtain -Not require heavy equipment in material transportation process -Aesthetics/neat appearance -Not require a special implementation method Implementing alternative IV (four) design, i.e., using precast L shape can cost-saving analysis is issued with 20 years old plan that is equal to IDR. 23,754,327,910. If it is compared with the use of river stone installation.

Conclusions
Based on the analysis results of Value Engineering that have been conducted on the project of DAS irrigation drainage improvement in Cengcengan River, Gianyar can be concluded as follows: a) From 4 (four) alternatives analyzed, alternative IV (four) is the best alternative that is by using precast L shape used in irrigation channel work by using the zero-one method. b) Cost savings gained after replacing stone pairs with precast L shape with 20 years old building plan is IDR. 23,754,327,910 with a time savings of precast L shape assembly work for 490 days.

Suggestions
1. If in a project required value engineering analysis, the analysis should be done at the planning stage. Therefore, the optimum potential savings are obtained without reducing the project quality. 2. Before value engineering is applied to a project, a clear agreement should be made regarding the results shared to be obtained between the owner, the contractor, and the value engineering consultant. 3. For closer results, we need to add more criteria reviews and more alternatives.