Optimizing Civil Contractor Selection for Sustainable Community Maintenance Projects Using Open Tender Systems

. The maintenance of production facilities is crucial to ensure their safe operation and long-term sustainability. Therefore, selecting the right civil contractor is essential to ensure that the job is performed efficiently and cost-effectively by the most qualified contractor. Currently, the contractor selection process involves three elimination stages and is carried out by two different departments, which may lead to biased and inconsistent scoring. To overcome these issues, this study proposes using the Analytical Hierarchy Process (AHP) method to select the highest-scoring contractor based on expert judgment criteria. The criteria and sub-criteria were determined through a focus group discussion with three experts, and each alternative analyzed with pairwise comparison, consistency index and calculation ratio. The results revealed that the technical criterion and commercial criterion were the highest-weighted criteria, while the administrative criterion was the lowest. Among the five pre-qualified contractors and fifteen sub-criteria evaluations, this study recommends PT NS as the highest scorer in the Project Maintenance Civil Community Open Tender System Selection. Therefore, it can be concluded that using the AHP method can increase the effectiveness and efficiency of difficult multi-criteria decision-making, especially in the open tender evaluation of criterion ranking of importance, resulting in sustainable maintenance of community projects.


Introduction
Indonesia is well-known for its energy and mineral resources.According to the Ministry of Energy and Mineral Resources Republic of Indonesia Report (2021), around 34.54% of oil and gas products are used for export trading, and 27.69% are used for fertilizer, petrochemical, and ceramic industry [1].One of the oil and gas products is Liquified Natural Gas (LNG), a colorless and odorless liquid fuel that offers energy efficiency, accessibility, and is cheaper than any other fossil fuel.From a gas well, natural gas is transported to a purification and liquefaction facility to change the natural gas form into liquid.At this stage, the gas is cooled to -160 degrees Celsius and atmospheric pressure before being condensed and stored in cryogenic tanks ready to be distributed to the end customer.
In an oil and gas company, maintenance project is a major lever for sustainable manufacturing, as it enables the company to maintain an efficient production system and produce products of the required quality.Maintenance affects various aspects of manufacturing, including production volume and costs, asset performance, equipment availability, final product quality, worker and end-user health and safety, and the surrounding natural environment and social welfare [2].Previous studies suggest that this practice can be achieved through an open tender system and evaluated by several experts' judgment [3].Evaluation aspects scored using multiple dimensions, resulting a complex decision-making process to search one trusted company to do the maintenance process [4].Moreover, Several researchers have proposed conceptual frameworks to help diverse stakeholders evaluate the impact of maintenance on three dimensions of sustainability [2].For instance, one framework was developed to measure the sustainability impact of maintenance activities, providing decision-makers from various company departments with a comprehensive overview of the effects on all sustainability dimensions [5].PT XYZ has also implemented similar practices for its Community Maintenance Projects, utilizing an open tender system to select the most suitable civil contractor for the projects.
PT. XYZ is a non-profit company in Bontang, East Kalimantan, Indonesia, with the primary operation of producing Liquified Natural Gas (LNG).Its production process is divided into three specific areas or departments, such as process train, utilities, and storage loading.The process train itself involves five plants that operate in a hazardous situation, particularly in an offshore plant where one failure or accident in the production facility can cause catastrophic damage [6].The distribution supply chain of LNG from the gas well to the end customer also involves many suppliers and distribution business partners.Therefore, to support their business, PT XYZ has several trusted and prequalified supplier selections that provide materials and services in a professional, systematic, transparent, reliable, and fair way.Moreover, to maintain its quality, a facility maintenance strategy is a must to ensure and sustain overall business process efficiency, profit margin, safety, and sustainability [7,8].As mentioned by several previous study, The importance of maintenance practices is underscored by the concept of sustainable development in various industries, which emphasizes the need for continuous existence.
In PT XYZ's materials and services procurement system, there are four methods that can be used, such as open tender procurement, open tender selection, open tender supplier evaluation process, and auction process.In the final contractor selection process, there must be a trade-off between cost, time, and quality [9,10].Moreover, the selection of the appropriate contractor is also critical for project success [11].However, in several studies, the tender price tends to dominate and increase the chance of a biased selection and evaluation process.Especially in the case study of PT XYZ, the open tender supplier evaluation has three stages of the evaluation process, which are administrative, technical, and commercial evaluation.For administration and commercial evaluation and elimination processes are determined by the contract section, while the technical evaluation-elimination process is done by the project originator or user.Hence, causing the project user to be unable to evaluate suppliers for each stage of evaluation and affecting the complicated decision-making process for supplier selection.
Even though the company could have had a more comprehensive and objective evaluation from the contract section and project originator, inconsistency and biased scoring might affect the satisfaction of project outcomes.Moreover, the importance of selecting the most qualified contractor is to minimize project failure and enhance performance [12,13].Several studies found that the Analytical Hierarchy Process can solve complex situations, such as the contractor selection process, which might be challenging because of conflicting criteria and involving several experts' judgments.Analytic Hierarchy Process (AHP) is a method created by Thomas L. Saaty to deal with multicriteria situation decision making [14].It assists many conflicting criteria of decision-making by establishing priorities among several decision factors to reach its goal.It can measure experts' judgments to find the priority scale of each decision criterion through pairwise comparison [15,16].In other literature, the AHP method is well-suited with the Multi-Criteria Decision Analysis (MCDA) approach for consistent decision-making based on qualitative inputs from a ratifying stakeholder [17].
This research aims to conduct an analysis of civil contractor selection for civil community project maintenance in an open tender system using AHP to identify the best civil contractors based on expert judgments and criterion ranking of importance.The study aims to provide recommendations for best practices in contractor selection to achieve a successful maintenance process in PT XYZ.

Research Methodology
Several researchers have proposed conceptual frameworks to help diverse stakeholders evaluate the impact of maintenance on three dimensions of sustainability [18].For instance, one framework was developed to measure the sustainability impact of maintenance activities, providing decision-makers from various company departments with a comprehensive overview of the effects on all sustainability dimensions [19].To incorporate the perspectives of multiple maintenance stakeholders in assessing the connection between critical maintenance factors and manufacturing sustainability, the Analytical Hierarchy Process (AHP) was utilized [20].Therefore, in this study, AHP is used to optimize the selection of civil contractors through an open tender system.
The Analytical Hierarchy Process (AHP) is an eigenvalue approach to pair-wise comparison that provides a methodology to calibrate the numeric scale for quantitative and qualitative measurements of performance [14].The scale used in the measurement usually ranges from 1/9 for "least valued than," 1 for equal value, and 9 for "absolutely more important than," thus covering the entire spectrum of the comparison.According to previous studies, after the comparison measurement survey by experts, it is important to model the problem into a hierarchy structure.The overall objectives of the problem to be solved by AHP are at the very top of the hierarchy, followed by the criteria to achieve the goals at level 2. It is then branched into several sub-criteria at level 3. Figure 1 below provides examples of a criteria hierarchy.The structured hierarchy used in problem modelling makes complex multi-criteria decision-making appear simpler.This method is then analyzed using pairwise comparison to ensure a fair scoring of experts' judgment.The pairwise comparison results in a matrix with values for criteria and sub-criteria, which can be difficult to calculate manually and requires software to test its consistency.In this study, Expert Choice v.11 is used to test consistency and calculate the weight of importance for each criterion and sub-criterion.The ranking of weights for each criterion and sub-criterion is then used to measure the overall score of all prequalified contractors.A consistency score of less than 0.1 is required for it to be considered acceptable [19,21].
To better understand the project maintenance civil community, open tender system, this study conducted a literature review in parallel with case study observations.The literature review focused on previous studies of Multi-Criteria Decision-Making (MCDM), Analytical Hierarchy Process (AHP), and open tender civil contractor selection.After identifying the problem, data was collected through Focus Group Discussions to decide on criteria and sub-criteria variables.A survey questionnaire was then developed to determine the rank of importance for all alternative criteria and sub-criteria.The results were then used to find the ranking of all the criteria and sub-criteria priority and weighing each contractor.However, before applying the AHP method, it was important to ensure that all collected data was consistent.
The AHP method was performed using Expert Choice v.11 software in the following steps: 1. Structuring all the criteria and sub-criteria decomposition hierarchy 2. Analyzing data using pairwise comparison matrix for each criterion 3. Calculating the priority for each criterion 4. Calculating the consistency index and ratio 5. Weighing or ranking the priority of each subcriterion 6. Weighing or ranking the priority of each alternative sub-criterion After analyzing all the data, priority scores for each criterion and alternative sub-criterion contractor selection were obtained.Thus, the contractor selection process based on expert judgment was carried out effectively.Figure 2 below illustrates the research methodology used in this study.

Results and Discussion
According to the company's standard operational procedure and rules, only pre-qualified contractors are eligible to participate in the open tender selection process.The procurement section conducts several certification and pre-qualification tests for civil contractor selection.However, due to the limited number of certified civil contractors, the open tender selection process becomes more competitive.In the absence of a standard weight or ranking for each criterion and sub-criteria, the selection process could be ineffective and inefficient.Thus, the aim of this study is to analyze the civil contractor selection process of the open tender system in the project civil community using AHP.Before selecting the contractors, standard criteria and sub-criteria must be decided for each evaluation and selection process.The standardization of criteria and sub-criteria was carried out through a Focus Group Discussion (FGD) involving the contract section and project originator experts.There are three criteria and fifteen sub-criteria, as shown in Table 1.Once the experts approved all the standard criteria and sub-criteria for all evaluation process, a contractor selection hierarchy model was made.Figure 3 below is the Contractor Hierarchy Selection Process based on decision network before proceeding to AHP process.Once the contractor hierarchy process was modelled, the experts were requested to complete a questionnaire that rated the importance of all the criteria and sub-criteria used in the evaluation process.The collected data was then integrated and analyzed through Experts Choice v.11 software.Figure 4 and 5 below illustrate the combination of pairwise comparison for all criteria and the weight combination results for both all and each criterion respectively.Therefore, based on the data analysis result, technical evaluation has the highest ranking of importance based on experts' judgement with inconsistency ratio 0.03.When applying the AHP method, the consistency ration must be less than 0.1, which means that all the weights were calculated correctly [18].Table 2 below shows the weigh for each criterion.

Conclusion
Maintenance projects are essential for achieving sustainable manufacturing in the oil and gas industry, impacting various aspects of production, including quality, costs, and safety.An open tender system and the use of conceptual frameworks can assist decisionmakers in evaluating maintenance practices and their impact on sustainability dimensions, enabling the selection of trusted companies to carry out maintenance projects effectively.Due to the increasing demand for Liquefied Natural Gas (LNG) in Indonesia's industrial and export sectors, PT XYZ are prompted to enhance the efficiency and effectiveness of the Contractor Selection Process in the Project Maintenance Civil Community Open Tender System.The open tender selection process was carried out through elimination with two separate sections without any integration of data and ranking of criteria importance.This research has successfully standardized the contractor selection process in the open tender system by determining the important criteria and subcriteria based on the judgement of three experts.All the criteria and sub-criteria for each contractor were then analyzed resulting in a list of recommended contractors based on the evaluation of experts.Thus, the civil contractor selection process can be carried out in an effective and efficient manner, with more objective results based on the analysis of the documents' criteria importance.
The research has identified the technical, commercial, and administrative criteria as the most to least important criteria in order, with weights of 0.421, 0.419, and 0.159, respectively.In terms of contractor selection based on their document evaluation by experts, PT.NS obtained the highest weight score (0.320), and hence, it is recommended for the civil community maintenance project.The AHP analysis has been advantageous in the Open Tender System as the civil contractor selection process remains standardized and consistent, even when the group of experts is restructured.
The study has its limitations, which include focusing only on the Civil Contractor Selection Process and Open Tender System.The future direction of this research would be to explore other procurement processes and expand the dataset and framework of supplier selections with other systems, providing more comprehensive results and increasing the process of multi-criteria decision making, and finding the optimal procedure and results for supplier selections.

Table 1 .
Criteria and Sub-Criteria Decision

Table 2 .
Weigh and Ranking for all Criteria

Table 3 .
Administrative Sub-Criteria Ranking

Table 4 .
Technical Sub-Criteria Ranking

Table 5 .
Commercial Sub-Criteria Ranking There are five certified contractors in this contractor selection for civil community maintenance project, namely PT NS, PT MLD, PT BMS, PT WKP, and PT ADS.Each contractors' documents were then collected, scored, and analyzed by experts.This research recommends the civil contractor selection based on the AHP Criterion and Sub-Criterion Priority Ranking.Table 6 below are results of the Contractor Selection Process.

Table 6 .
Contractor Selection Process