SELECTION MODEL OF CONSTRUCTION METHOD USING PAIRWISE COMPARISON MATRIX

Transcription

1 International Journal of Civil Engineering and Technology (IJCIET) Volume 9, Issue 11, November 2018, pp , Article ID: IJCIET_09_11_087 Available online at ISSN Print: and ISSN Online: IAEME Publication Scopus Indexed SELECTION MODEL OF CONSTRUCTION METHOD USING PAIRWISE COMPARISON MATRIX Professor, Department of Architectural Engineering, Songwon University, Gwangju, 61756, Republic of Korea _ ABSTRACT Various construction methods are being developed in accordance with the highrise, complexed and large-scale buildings. This is leading to the importance of selecting a construction method for major works. In practice, however, the characteristics of the project are not fully taken into consideration when selecting the construction method. There is also lack of objective criteria and data for selecting of major construction methods. It has been pointed out that the selecting of constructions methods in practice depends on the experience and intuition of the person in charge. In order to solve these problems, the study on the selecting of construction methods using artificial intelligence theory such as Fuzzy Theory, Analytical Hierarchy Process and Case-Based Reasoning was conducted. However, in practice, when selecting the construction method, it is difficult to apply selection models of various construction methods to each major work in consideration of the field condition and the characteristics of each work. In order to solve these problems, this study proposed a decision-making support model that is easy to use in practice by using the Pairwise Comparison Matrix. The consistency of the study model was verified by applying this study model to the selection process of the soil retaining wall method. Keyword head: Construction Method, Pairwise Comparison Matrix, Weight, Decision-making. Cite this Article:, Selection Model of Construction Method Using Pairwise Comparison Matrix, International Journal of Civil Engineering and Technology, 9(11), 2018, pp editor@iaeme.com

2 1. INTRODUCTION 1.1 Background and purpose of study Recently, due to the development of various construction methods, the number of applicable construction methods is increasing, and the importance of selecting construction methods for major works is emerging. Choosing a reasonable construction method in the construction planning phase for the smooth execution and success of a construction project is an important factor to perform a project successfully [1]. However, the current method does not fully consider the characteristics of the project when selecting the construction method. In addition, there is also lack of objective criteria and data for selecting of the construction method. It has been pointed out that the selecting of constructions method in practice depends on the experience and intuition of the person in charge. These problems cause changes of construction methods during construction, safety accidents, quality degradation of buildings, and increase of construction cost and construction duration. Also, the construction method selected without consideration of field conditions is causing civil complaints due to noise and dust. Therefore, it is necessary to analyze the factors affecting the project in the construction planning phase to select the most appropriate construction method. This study analyzed the characteristics, safety and economics of the project in the construction planning phase and presented a model to support the decision-making of practitioners when selecting the construction method for the major work. 1.2 Scope and method of study The scope of this study is to propose a model to support decision-making when selecting the construction method for the major work in the construction planning phase and this study was conducted by the following procedure and method. 1) In the construction planning phase, the problems of the selection method of existing construction method and the previous study for improvement were reviewed. 2) When selecting the construction method, the major factors to be considered were defined. 3) A model for selection procedure of construction method and decision-making support was presented. 4) A case study was conducted to select the soil retaining wall method to verify the consistency of the study model. 5) The results of this study were summarized and the applicability of this study was suggested. 2. PROBLEMS OF SELECTION METHOD OF EXISTING CONSTRUCTION METHOD AND REVIEW OF PREVIOUS STUDY The selection method of existing construction method reduces the number of alternatives for a number of applicable construction methods. Since the selection method of existing construction method is often focused on project planning, the systematic analysis of ordering conditions and field conditions is neglected. There are also many cases that rely on the tacit knowledge and intuition of the engineers in charge. With these methods, it is difficult to systematically apply the various factors that can be derived depending on the ordering conditions and the field conditions due to the characteristics of the construction work. In addition, in the case of a problem that cannot be taken into consideration during the construction planning phase, it may cause a decrease in productivity due to design changes, construction method changes and safety accidents. Studies on the selecting of various construction methods have been carried out to solve these problems. When selecting the non-exposed waterproofing methods applied to the rooftop of apartment house, Choi, S. M., et al. derived evaluation items by comprehensively reviewing the material performance, constructability and economics. Based on the objective editor@iaeme.com

3 Selection Model of Construction Method Using Pairwise Comparison Matrix evidence, he set the importance level between the evaluation items and proposed the evaluation criteria that can select the optimal waterproofing method in accordance with the field condition [3]. Kang, D. W., et al. selected standard work type by presenting a simulation model based on historical data for the formwork method of apartment house [4]. Kim, S. G., et al. compared the performance of representative formwork methods that are typically used using Case-based Reasoning and Analytical Hierarchy Process [5]. Kim, J. Y., et al. proposed a knowledge system based on Neural Network Theory and Case-based Reasoning for selecting soil retaining wall method [6]. Lee, D. U. and Kim, K. W. presented a method to select optimum construction method using Fuzzy Analytical Hierarchy Process, which combines the multiple criterion decision-making method with Fuzzy Theory [7]. Kim, B. S., et al. presented a selection model of demolition method that reflects the characteristics of the remodeling project [8]. Like this, various studies have been conducted to select the optimum construction method for major work by using artificial intelligence theory such as Neural Network Theory, Analytical Hierarchy Process, Case-based Reasoning and Fuzzy Theory. However, in practice, it is difficult to apply different selection model of construction method to each major work in consideration of characteristics of each work and field conditions when selecting the construction method. This study proposed a decision-making support model for selecting optimal construction method which is easy to use in practice. 3. SELECTION MODEL OF OPTIMUM CONSTRUCTION METHOD The selection model of the construction method proposed in this study is to select the optimum construction method for the major work of the construction project. Through the analysis of the project characteristics, a plurality of construction methods that can be adopted were selected, and the efficiency of decision-making was enhanced by indexing the goodness of fit of the construction method according to the characteristics of the project. This study model is composed of 6 steps: 1) selection of the corresponding work, 2) project characteristics analysis, 3) selection of applicable construction methods, 4) safety analysis, 5) economic analysis and 6) selection of optimum construction method. The procedure and contents of this study model are as follows. Step 1: Selection of the corresponding work Classify the work that constitutes the project and select a classification level that is easy to select the construction method for the corresponding work using the Classification of Construction Information [9] proposed by the Ministry of Land, Infrastructure and Transport, which governs the construction industry in Korea. Table 1 shows the composition of middle classification work and small classification work in soil retaining and timbering work. The construction method of 242_Peristyle earth retaining can be applied by selecting the optimal construction method according to the project characteristics among 2421_Steel pope peristyle earth retaining, 2422_Cast-in-place peristyle earth retaining, 2423_Installation levee concrete peristyle earth retaining and 2424_Soil peristyle earth retaining editor@iaeme.com

4 Table 1 Classification system of construction information (Parts) Code_Large Classification Code_Middle Classification Code_Small Classification 241_Pile earth retaining 2411_H-pile soldier pile earth retaining 2412_Sheet pile earth retaining 2413_Steel sheet pile earth retaining (H-Beam & timber) 2414_Lightweight Steel sheet earth retaining 2415_Steel pipe pile earth retaining 242_Peristyle earth retaining 2421_Steel pipe peristyle earth retaining 2422_Cast-in-place peristyle earth retaining 2423_Installation levee concrete peristyle earth retaining 2424_Soil cement peristyle earth retaining 24_Soil retaining & timbering work 243_Sheet Pile - 244_PC consecutively wall earth retaining - 245_Diaphragm wall earth retaining - 246_Earth retaining timbering work 2461_Wood timbering work 2462_Steel timbering work 2463_Steel pipe timbering work 2464_RC timbering work 247_Earth anchor, Rock anchor earth retaining - 248_Self-assembly simplicity earth retaining - Step 2: Project characteristics analysis The three management elements of a construction project are time, quality and cost. Including safety and environment in three management elements of a construction project, it is defined as five management elements of a construction project [10]. In this study, to analyze the characteristics of the project for selecting of the construction method, the five management elements of a construction project, which are time, quality, cost, safety and environment, were reconstructed into ordering conditions and field conditions. The ordering conditions are construction cost, construction duration, required performance and client's requirements. The field conditions are geographical conditions, surrounding conditions, ground conditions and climatic conditions. Therefore, the three management elements of the construction project are time, quality, and cost, which are the ordering conditions, and the safety and environment, which corresponds to the five management elements of the construction project, are the field conditions. Step 3: Selection of applicable construction methods Search for cases with similar conditions to the target project and analyze the ordering conditions and field conditions to select multiple construction methods that can be adopted for the corresponding work. Step 4: Safety analysis The structural safety and work safety of the corresponding construction method are reviewed for applicable construction methods selected in Step 3. Safety should be considered as a priority factor for safety of workers during construction and items affecting safety of users after completion. Therefore, the next step of the economics review is conducted for the construction methods that have passed the safety analysis editor@iaeme.com

5 Selection Model of Construction Method Using Pairwise Comparison Matrix Step 5: Economic analysis Calculate the construction costs of the construction methods that have secured structural safety and work safety selected in Step 4. Analyze the life-cycle cost when there is a running cost of structures, spaces and elements implemented through the construction method. If there is no running cost, only the construction cost, which is the initial cost, is analyzed. Step 6: Selection of optimum construction method Derive the weights of each influence factor by comparing the ordering conditions, field conditions, safety and economics affecting the major work that makes up the construction work. Afterwards, analyze the goodness of fit of each construction method and calculate the goodness of fit index for efficiency when making a decision. Step 6-1: Calculation of weight by influence factors Using the 'Matrix Analysis Method A' in Figure 1, weights are calculated by comparing the importance of the factors (hereinafter, influence factors) that affect the corresponding work defined in Step 2. As shown in the example of Figure 1, 2 points are given to important and 1 point is given to equal by comparing between the influence factors. The importance score is then calculated by summing the scores of each influence factor. When comparing the importance of 'Influence factor I' and 'Influence factor II', if 'Influence factor II' is judged to be more important than 'Influence factor I', 'II' is marked to the matrix of the point where 'Influence factor I' and 'Influence factor II' meet and 2 points of importance are added to 'Influence factor II'. When comparing the importance of Influence factor III and Influence factor IV, if Influence factor III and Influence factor IV have the same importance, III/IV is marked to the matrix of the point where Influence factor III and Influence factor IV meet and 1 point is added to Influence factor III and Influence factor IV. Define the total of importance as '1', transform the size of the evaluation value and use it as weight () in Step 6-3. Figure 1. Example of matrix analysis method A Step 6-2: Calculation of the goodness of fit by construction methods for influence factors Using the 'matrix analysis method B', calculate the goodness of fit score of the applicable construction methods for the influence factors defined in Step 2. As shown in the example of Figure 2, the range of the score is given as 2 points for 'excellent' and 1 point for 'equal' in the comparison between the construction methods, and the goodness of fit score is calculated by editor@iaeme.com

6 summing the scores of each construction method. When comparing the importance of 'Construction method I' and 'Construction method II', if Construction method II' is judged to be more important than Construction method I', 'II' is marked to the matrix of the point where Construction method I' and Construction method II' meet and 2 points of the goodness of fit score are added to 'Construction method II'. When comparing the importance of 'Construction method III' and 'Construction method IV', if 'Construction method III and 'Construction method IV have the same importance, III/IV is marked to the matrix of the point where 'Construction method III and 'Construction method IV meet and 1 point is added to 'Construction method III and 'Construction method IV. Ordering condition (b) Field condition editor@iaeme.com

7 Selection Model of Construction Method Using Pairwise Comparison Matrix (c) Safety (d) Economics Figure 2 Matrix analysis method B Step 6-3: Calculation of goodness of fit of integrated by construction methods Goodness of fit of integrated (Z) is calculated that reflects the importance by multiplying the weight (Z) by influence factors in Step 6-1 and the goodness of fit (Y) of each construction method for influence factor in Step 6-2. The mathematical model for calculating the goodness of fit of integrated is shown in Equation 1 below. Z= ( ), Here, Z is goodness of fit of integrated, X is weight, Y is goodness of fit for each influence factor of the construction method, j is the influence factor, and k is the construction method. (1) editor@iaeme.com

8 Step 6-4: Calculation of goodness of fit index by construction methods Goodness of fit of integrated can cause confusion in decision-making due to the various range of values calculated according to the influence factors and the number of construction method of comparison target. Therefore, in this study, goodness of fit of integrated is normalized and calculated to a certain extent to improve efficiency when making a decision. The reason for calculating the goodness of fit index for each construction method is to improve the efficiency of decision-making by comparing the gap of the subordinate index based on the maximum value of goodness of fit index. The maximum value of goodness of fit of integrated calculated in step 6-3 is defined as '1'. Next, the goodness of fit of integrated of each construction method is linearly transformed and the goodness of fit index is calculated by construction methods. The mathematical model for calculating the goodness of fit index is shown in Equation 2 below. = (2) Here, is the goodness of fit index, is the maximum value of the goodness of fit of integrated by construction methods, is the goodness of fit of integrated of the construction method, is the goodness of fit of integrated of the construction method and is the goodness of fit index. 4. CASE STUDY A case study was conducted by applying the soil retaining wall method for the verification of the consistency of the study model. In recent years, underground works have been increasing in size to utilize underground spaces for parking spaces and commercial facilities. In addition, construction methods for underground construction are diversified and specialized. Underground construction is one of the large-scale works that has 20% to 40% of construction cost. The selection of the soil retaining wall method in underground construction is an important work for the successful implementation of the project. Therefore, it is necessary to select a proper construction plan and appropriate construction method for soil retaining wall construction. However, due to the failure to select a soil retaining wall method suitable for the site, the soil retaining wall collapse causes accidents [11]. The selection of the soil retaining wall method that has the purposes of work safety, prevention of heaving, prevention of boiling and prevention of surrounding damage is different depending on the field condition. However, the current selection of the soil retaining wall method is made through a simple comparison between the construction methods by the subjective judgment of the person in charge of site. 4.1 Application of study model Step 1: Selection of the corresponding work The soil retaining wall method includes pile earth retaining, peristyle earth retaining, sheet pile, PC consecutively wall earth retaining and diaphragm wall earth retaining as defined in classification system of construction information of Table 1, and one of these can be applied. Step 2: Project characteristics analysis In order to select the soil retaining wall method, the ordering conditions such as the client's requirements, the size of the building and the construction duration, and the field conditions such as the condition of the adjacent building, the height of the site and the surrounding conditions were investigated. The case site is an office building built in the downtown area. The foundation digging depth of the site is G.L -20m and the foundation digging area of the site is 5,325m 2. In addition, when underground strengthening, groundwater pollution measures, editor@iaeme.com

9 Selection Model of Construction Method Using Pairwise Comparison Matrix noise reduction measures and vibration reduction measures are required, and there is a requirement of the client to request a reduction of construction duration of four months. Step 3: Selection of applicable construction methods Using the characteristics of soil retaining wall method [12] in Table 2, the construction methods suitable for ordering condition and field condition were selected. H-pile + retaining wall (hereinafter, H-pile), cast in concrete pile (hereinafter, CIP), soil cement wall (hereinafter, SCW) and diaphragm wall (hereinafter, D-wall) were selected as applicable to the case site. Table 2 Characteristics of soil retaining wall methods applicable to the case site Considerations Method Conventional type 20 C C C B A A A A H-pile Auger-Combined press-in 25 C A C C A A A A Field mortar poles 36 C A A B A A A A CIP Conventional type 36 B A A A A A A A Impermeable type 30 B A A B A A A A SCW Shape steel 30 A A C B A A A A Steel pipe 30 A A C C A A A A D-wall Drill 100 A A A C A A A A Bucket 50 A A C A A A A A Note: 1 - Depth(m), 2 - Waterproof Performance, 3 - Noise & Vibration, 4 - Soil, 5 - Rock, 6 - Boulder, 7 - Gravel, 8 - Sand, 9 - Clay, 10 - Soft, 11 - Hard, A - Possible, B - Average, C- Difficult Step 4: Safety analysis The safety of applicable construction methods was analyzed. As shown in Table 3, the maximum displacement of the applicable construction methods is H-pile: 101.3mm, CIP: 52.6mm, SCW: 149.3mm, and D-wall: 15.6mm. However, all four construction methods are analyzed to be able to secure safety in proper design. Method Framework Maximum displacement(mm) Walls(mm) Strut(mm) Table 3. Safety data of applicable construction methods H-Pile CIP SCW D-wall CIP: Ø400 Side H-Pile: H-Pile: SD 40f y=4000kg/cm 2, f ck=300kg/cm 2 Slab Thickness: 300 Step 5: Economic analysis The construction cost was calculated to review the economics of the first selected construction methods. It was analyzed that the H-pile costs 72,000 per unit area (m 2 ). It was analyzed that the SCW costs 280,000 per unit area (m 2 ). It was analyzed that the CIP costs 180,000 per unit area (m 2 ). It was analyzed that the D-wall costs 210,000 per unit area (m 2 ). Thus, editor@iaeme.com

10 H-pile was analyzed as being the most economical. Next, with the order of CIP, D-wall and SCW were analyzed as economical. Step 6: Selection of optimum construction method Step 6-1: Importance analysis Six experts in the field of soil retaining wall method discussed and conducted a pairwise comparison on the importance of the ordering condition, field condition, safety and economics in case sites. Pairwise comparison results were used to analyze the importance of each influence factor and to calculate the weights. The importance of each influence factor was calculated as follows: Ordering condition: 4, Field condition: 1, Safety: 6 and Economics: 1. The weights of each influence factor was calculated as follows: Ordering condition: 0.33, Field condition: 0.08, Safety: 0.5 and Economics: Figure 3 shows the importance analysis and weight calculation process for the influence factors. Figure 3. Importance analysis and weight calculation data for influence factors Step 6-2: Calculation of the goodness of fit by construction methods for influence factors Six experts in the field of soil retaining wall method, who participated in the importance analysis in step 6-1, conducted a pairwise comparison of the superiority of the applicable construction methods for the influence factors through discussion. The goodness of fit score and the goodness of fit were calculated by using the pairwise comparison results. Figure 4 shows the goodness of fit calculation process for the influence factors. D-wall and H-pile were the most suitable for the ordering conditions. SCW and CIP were the most suitable for the field conditions. For the safety, D-wall was analyzed to be the most suitable, followed by CIP. H-pile was the lowest in the construction cost for evaluating the economics. D-wall is evaluated as the most economical method in the long term because it has the advantage of being used as a structure without dismantling even after the soil retaining wall work of the building editor@iaeme.com

11 Selection Model of Construction Method Using Pairwise Comparison Matrix (a) Ordering condition (b) Field condition (c) Safety

12 (d) Economics Figure 4. Shows the goodness of fit score calculation data by construction methods for the influence factors. Step 6-3: Calculation of goodness of fit of integrated The goodness of fit of integrated (Z) was calculated using the weighs (X) of each influence factor and goodness of fit (Y) of each construction method calculated above. Table 4 shows the goodness of fit of integrated calculation data that reflects the weights of each influence factor. D-wall has goodness of fit of integrated of 0.40 and is the highest. Next, with the order of CIP:0.30, H-pile:0.22 and SCW:0.10 were analyzed. Step 6-4: Calculation of goodness of fit index by construction methods The goodness of fit of integrated of the construction methods was substituted into Equation 2 to calculate the goodness of fit index. The goodness of fit index is the normalized value of the goodness-of-fit of integrated to improve the efficiency of decision-making when selecting an optimal construction method. Therefore, the goodness of fit index of the D-wall with the highest goodness of fit of integrated is 1 as shown in Table 5. Next, the goodness of fit index of CIP: 0.75, H-pile: 0.55 and SCW: 0.25 was calculated. Ordering condition X 1=0.33 Table 4 Goodness of fit of integrated calculation data Field condition X 2=0.08 Safety X 3=0.50 Economics X 4=0.08 Goodness of fit of integrated (') H-pile 0.33 x x x x SCW 0.08 x x x x CIP 0.25 x x x x D-wall 0.33 x x x x editor@iaeme.com

13 Selection Model of Construction Method Using Pairwise Comparison Matrix Table 5 Goodness of fit index calculation data Goodness of fit of integrated (() Goodness of fit index ()) H-pile /0.40=0.55 SCW /0.40=0.25 CIP /0.40=0.75 D-wall /0.40= CONCLUSION This study analyzed the ordering condition, field condition, safety and economics in the construction planning phase of the construction project and presented a model that can select the appropriate construction method for the project. This study model was designed using the Pairwise Comparison Matrix and the study model is as follows. 1) Matrix analysis model A for deriving the weight by analyzing the importance between influence factors 2) Matrix analysis model B for analyzing the extent to which the applicable method is appropriate for the influence factors 3) Goodness of fit of integrated model to integrate the goodness of fit and the weight of influence factors 4) Goodness of fit index calculation model to improve the efficiency of decision-making when the selection of construction methods for major works is repeated The consistency of the study model was verified by applying the construction method selection model proposed in this study to the case of selecting the soil retaining wall method. This study suggests that the effectiveness of decision-making can be improved by quantifying the goodness of fit of the construction method according to the project characteristics when selecting the main construction method. In addition, if the results of this study are applied to practice, it will be possible to secure objectivity and transparency on the construction method selection of the major work. Through this study, it is expected that the proposed optimal construction method selection process and mathematical model can be used to select the construction method of various works. ACKNOWLEDGEMENTS This research was supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education(2017R1D1A3B ) editor@iaeme.com

14 REFERENCES [1] Choi, O. Y., Cho, H. G., Kim, G. H. The Selection of Roof Waterproofing Methods using the Analytic Hierarchy Process (AHP) Technique, Journal of the Korea Institute of Building Construction, 10(4), 2010, pp [2] Seo, H. M., Shin, N. R. Yeom, D. J., Kim, Y. S. A Decision Support Model for the Selection of Exterior Wall Formwork in Residential-Commercial Building Construction, Journal of the Architectural Institute of Korea Structure & Construction, 29(9), 2013, pp [3] Choi, S. M, Joo, M. S, Oh, S. K. A Study on the Weight Decision and Applicative Estimation for Selecting the Non-Exposed Waterproofing Methods on the Roof of an Apartment Houses, Journal of the Architectural Institute of Korea Structure & Construction, 29(5), 2013, pp [4] Kang, D. W., Moon, H. S., Hyun, C. T. Development of a Simulation Model for the Productivity Analysis of Form Work in Multi-Family Housing Construction projects, Journal of The Korean Institute of Building Construction, 9(2), 2009, pp [5] Kim, S. G., Lee U. K., Cho, H. H., Kang, K. I. Decision Support System for Slab Formwork Selection of High-rise Building Construction, Journal of the Architectural Institute of Korea Structure & Construction, 22(11), 2006, pp [6] Kim, J. Y, Park, U. Y., Kim, G. H. A Study on the Selection of Retaining Wall Methods Using Neural Networks and Case-Based Reasoning, Journal of the Architectural Institute of Korea Structure & Construction, 22(5), 2006, pp [7] Lee, D. U., Kim, K. W. A Study on the Construction Method selecting scheme using Fuzzy Relative Preference Ratio method, Korean Journal of Construction Engineering and Management, 5(5), 2004, pp [8] Kim, B. S, Kim, T. H, Park, C. S. A Selection Model of Demolition Method considering the Characteristics of Remodeling Project, Journal of the Architectural Institute of Korea Structure & Construction, 22(2), 2002, pp [9] Ministry of Land, Infrastructure and Transport, Classification of Construction Information, [10] Martin B. Construction project management, International Journal of Project Management, 6(2), 1988, pp [11] Bae, C. H. A study on the selection of retaining wall system for the underground. Ph.D. Dissertation, Chungnam National University: Architectural Engineering, Graduate School of Industry Technology, [12] Lee, J. S. A Selection Model for Soil Retaining Walls in Construction Projects, Journal of Asian Architecture and Building Engineering, 11(2), 2012, pp editor@iaeme.com