Applying Value Engineering to Evaluate the Use of
Concrete in an Underground Railway Construction
Project
Chung-Fah Huang
Associate Professor, Dep. of Civil Eng. National Kaohsiung Univ. of Applied Sciences Kaohsiung City, Taiwan
Jeffrey@cc.kuas.edu.tw
Kung-Lung Lo
Ph.D. Student, Dep. of Civil Eng.
National Kaohsiung Univ. of Applied Sciences Kaohsiung City, Taiwan
Yun-Wu Wu
China Univ. of Technology Taipei City, Taiwan Department of Architecture
Her-Yung Wang
Professor, Dep. of Civil Eng.
National Kaohsiung Univ. of Applied Sciences Kaohsiung City, Taiwan
Abstract: the object of this research is an underground railway construction project. The railway will be 8.23 kilometers long with three stations located along it. The project will cost totally NT$ 29.36 billion and take seven years and eight month to complete. The total amount of concrete used in this project is estimated to be as large as 56,900 cubic meters. By using the value engineering technology, this study evaluated totally five concrete alternatives for the construction project. According to the findings of this research, self-compacting concrete (SCC) is the best alternative for it can help to save nearly NT$80 million, that is 24.8% of the original budget of NT$352 million for concrete. The amount of cement required for the project is half the amount of regular concrete project. In addition to cutting costs, SCC is more environmentally friendly for it uses industrial wastes as its ingredients. It is known as the green concrete for it is helpful in reducing carbon emissions and, hence, mitigating the greenhouse effects. The findings and suggestions of this study were sent to the authorities in charge of the project and have been accepted and adopted by the engineering consultants in the underground railway construction.
Keywords: value engineering; self-compacting concrete (SCC); energy conservation
I. INTRODUCTION
Value engineering (VE), also called value analysis or value management, is a simple and yet useful technology of management. Application of VE in engineering is, simply put, to study how to cut engineering costs and enhance the values of engineering [1]. In practice, a team would be set up to evaluate the planning and design of a specific project using VE methods. By detecting and excluding unnecessary expenses, the team then proposes the best alternative in terms of costs, reliability and performance for the reference of high-rank
management in their decision-making. [2]
As people are more concerned about the environment, there will be more stringent environmental standards and regulations in the 21st century. Production of a ton of cement generates a ton of CO2. 7% of the global carbon emission comes from the cement industry. In addition, cement is a construction material that consumes relatively more energy. Therefore, reducing the use of cement has its environmental urgency and value. In addition, recycling of industrial wastes, such as fly ash and slag, can play an important role in environmental protection. Apart from helping to reduce the use of cement, recycling of these wastes actually helps to improve the quality of concrete for the particles in the wastes are the best catalysts for pozzolanic reaction. Another ecological concern about concrete is to find out how to increase the durability of concrete structures by making concrete less vulnerable to deterioration. That will help reduce costs for building demolition and/or reconstruction, save natural resources and help the ecology [3].
When it comes to the workability of concrete, if the American Concrete Institute’s (ACI) minimum requirements of slump are used in the construction industry, workers will be forced to add more water in the mortars to make it more fluid for pumping. However, that will result in problems of concrete quality deterioration, such as insufficient strength, efflorescence or surface chalking. Finding how to meet the requirements of workability without causing these problems is a challenge and a responsibility for regulators, concrete mix proportion designers, engineers, and constructors.
Based on the above-mentioned concerns, self-compacting concrete (SCC) can be seen as the best alternative for construction for it uses a lot of industrial wastes (pozzolanic materials) in its mix. This not only
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Table 1. Feasibility Evaluation
Judgment Feasibility Evaluation
Analysis Object: concrete alternatives for the XXX underground railway construction project
Analysis Items
A five-point scale is used to evaluate how much each concrete fits the description of each analysis item with 0 meaning not all and 5 meaning very much.
A. S af ety B. E con om y C. E col o g y D. B eau ty E . Du ra b ility F . W o rk ab ility Total 1. SCC 5 5 4 5 4 5 28 2. LWAC 3 3 5 3 1 4 19 3. RAC 3 3 3 3 2 1 15 4. NFC 1 2 5 1 2 2 13 5. GFRC 1 1 3 2 1 1 9
Table 2. Weighted Evaluation
Judgment Weighted Evaluation Analysis Object: concrete alternatives for the XXX underground railway construction projects
Goals and Expectation Standards Original Scor Weight
A. Practicability 6 6 B. Technological Feasibility 4 4 C. Information Accessibility 0 0 D. Time Feasibility 6 6 E. Financial Effects 9 9 F. Public Acceptance 0 0
Table 3. Evaluation Matrix
Concrete Alternative Expected Standard Practice ability Technological Feasibility Information Availability Time Feasibility Financial Effects Public Acceptance Total Weight 6 4 0 6 9 0 Original Design: traditional concrete Score 5 5 5 5 5 5 4 4 4 4 4 4 3 3 3 3 3 3 2 2 2 2 2 2 1 1 1 1 1 1 Subtotal 30 20 0 30 27 0 107 Alternative 1: SCC Score 5 5 5 5 5 5 4 4 4 4 4 4 3 3 3 3 3 3 2 2 2 2 2 2 1 1 1 1 1 1 Subtotal 24 20 0 30 45 0 129 Alternative 2: LWAC Score 5 5 5 5 5 5 4 4 4 4 4 4 3 3 3 3 3 3 2 2 2 2 2 2 1 1 1 1 1 1 Subtotal 18 20 0 12 18 0 68
Table 4. Original Budget Plan Using Traditional Concrete (total amount: 56900m3)
Item Unit (NT$) Amount Subtotal (NT$) 1. Pre-mixed and
high-pressure pumped mortars 3,213 56,900(m 3
) 182,819,700 2. Technicians 40 3(person/m3
) 6,828,000 3. Unskilled Workers 144 12(person/m3
) 98,323,200 4. Pumps 90 4(unit/m3 ) 20,484,000 5. Tool Wear 26 30(%/m3 ) 44,382,000 Total - - 352,836,900
Table 5. Budge Plan Using SCC (total amount: 56900m3)
Item Unit Price
(NT$) Amount
Sub-total (NT$) 1. Pre-mixed and
high-pressure pumped mortars 3,242 56,900(m 3
) 184,469,800 2. Technicians 40 2(person/m3
) 4,552,000 3. Unskilled Workers 144 5(person/m3
) 40,968,000 4. Pumps 90 4(unit/m3) 20,484,000 5. Tool Wear 26 10(%/m3 ) 14,794,000 Total - - 265,267,800 REFERENCES
[1] Chen, W.T., Chang, P.Y. and Huang, Y.H., “Assessing the overall performance of value engineering workshops for construction projects ” International Journal of Project Management, 28(5), pp. 514-527, 2010.
[2] Lin, H.Y., Evaluation and Analysis of Performance of Self-Compacting Concrete Used in Construction, M.A. Thesis of the Civil Engineering Department, National Taiwan University, 2002. (in Chinese)
[3] Samy, E.G., “Value Engineering, a powerful productivity tool”, Computers & Industrial Engineering, 35, pp. 381-393, 1998. [4] Persson, B. “Eight-year exploration of shrinkage in
high-performance concrete” Cement and Concrete Research , 32 (8), pp. 1229-1237, 2002.
[5] Prasada, K. R. Eskandari, H. and Reddy, B.V. “Prediction of compressive strength of SCC and HPC with high volume fly ash using ANN”, Construction and Building Materials, 22(4), pp. 456-462 April 2008.
[6] West, R.P., “Self-compacting concrete”, Concrete Today, Irish Concrete Federation, pp.7-9, 2003.
[7] Chandra, S. and Berntsson, L. “Self-compacting concrete: An analysis of 11 years of case studies”, Cement and Concrete Composites, 28(2), pp. 197-208, 2006.