A comprehensive framework for assessing and selecting appropriate scaffolding based on analytic hierarchy process

Transcription

1 Journal of Safety Research 34 (2003) A comprehensive framework for assessing and selecting appropriate scaffolding based on analytic hierarchy process Dongping Fang a, *, Qiping Shen b, Shenghou Wu c, Guiwen Liu d a (Tsinghua University-Gammon Skanska) Construction Safety Research Center, School of Civil Engineering, Tsinghua University, Beijing , China b Department of Building and Real Estate, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China c B. A. Real Estate Investment Consulting Co., Ltd. Rm1101, Building B, Huixin Plaza, No. 8 Anli Road, Andingmenwai, Beijing , China d Department of Building and Real Estate, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China Received 10 December 2002; received in revised form 13 March 2003; accepted 27 May 2003 Abstract Problem: Bamboo scaffolding has been widely used in South China, Hong Kong, and Southeast Asia for many years. Bamboo scaffolding is more economical, but its safety record is relatively poor. Conversely, metal scaffolding is more expensive, but its use in these regions has increased in recent years because it is relatively safe. The assessment and selection of the most appropriate type of scaffolding for a particular construction project is always a concern for project managers. Method: This paper suggests a comprehensive assessment framework that enables project managers to take a number of major quantitative and qualitative factors into consideration when making scaffolding decisions. This framework is based on the Analytic Hierarchy Process methodology and a survey among project managers in Hong Kong. Results: The research reveals that the overall performance of metal scaffolding is believed to be better than bamboo scaffolding. A sensitivity analysis has also been conducted to investigate the impact of various factors on the final decisions. Impact on Industry: The proposed assessment framework can be used as a supporting tool for project managers in the selection of scaffolding for their projects. D 2003 National Safety Council and Elsevier Science Ltd. All rights reserved. Keywords: Analytic hierarchy process; Safety; Assessment and selection; Bamboo scaffolding; Metal scaffolding 1. Introduction The importance of scaffolding is well known and understood by construction professionals. Bamboo scaffolding has a relatively long history of use in South China and Southeastern Asia. In Hong Kong, various forms of bamboo scaffolding have been used in building construction, repairs of external walls, decorations, slope maintenance, sign erection, and other projects that require a temporary structure to support working platforms (Tong, 1998). Although bamboo scaffolding has its merits in cost and flexibility, its safety record has not been satisfactory. Fig. 1 shows the number of fatal accidents in Hong Kong due to problematic scaffolding; this has been a topic of debate for a considerable period of time. On one hand, it is believed that bamboo * Corresponding author. Tel.: ; fax: address: fangdp@tsinghua.edu.cn (D. Fang). scaffolding provides a flexible, practical, and economical means of support on which work can be carried out safely. Standards and codes of practice concerning materials testing, design, construction, maintenance, and inspection are required to achieve optimal safety (Fu, 1993). On the other hand, some people believe that bamboo scaffolding should be banned in Hong Kong, as it has been in many other countries (Mak, 1998). Both bamboo scaffolding and metal scaffolding have advantages and disadvantages. Previous research tends to focus on a single type of scaffolding with little effort to compare various scaffolding types. Wu (2002) made a safety assessment on two types of scaffoldings and arrived at an average accident risk index score of 0.65 for bamboo scaffolding and 0.35 for metal scaffolding. Wong (1998) conducted a detailed study of the safety aspect of bamboo scaffolding, from the point of purchasing bamboo, to designing, constructing, maintaining, and finally, dismantling. He made a set of useful recommendations in these areas. Chan, Wong, So, and Poon (1998) developed a /$ - see front matter D 2003 National Safety Council and Elsevier Science Ltd. All rights reserved. doi: /j.jsr 转载

2 590 D. Fang et al. / Journal of Safety Research 34 (2003) Fig. 1. Fatal accidents in Hong Kong due to problematic scaffoldings (all types). computer program that attempted to calculate the loadings during the design of bamboo scaffolding and make the calculation more accurate. Wu (2002) conducted a detailed study on the cost of scaffoldings in Hong Kong. It was found that bamboo scaffolding is relatively cheaper with a price of HK$100/ m 2 while metal scaffolding is more expensive with a price of HK$210/m 2, partially due to its small market share. With the growth of the market share, it is possible for metal scaffolding s cost to fall off to HK$150/m 2. Although a number of studies have been undertaken in the past to investigate various aspects in the assessment and selection of scaffoldings, little has been done to provide a comprehensive solution to this complex problem of scaffolding selection faced by many construction project managers. This paper aims to introduce a comprehensive assessment framework for evaluation, comparison, and selection of different types of scaffoldings, taking all major factors into consideration through the use of the Analytic Hierarchy Process (AHP). 2. Research methodology The selection of a suitable type of scaffolding for construction projects is a very complex process. Many factors, such as safety and cost, should be taken into consideration. Metal scaffolding is relatively safer, but costs more. Bamboo scaffolding has relatively low cost, but its safety record is also low. The appropriate solution to this kind of complex and multi-criteria problem is to divide the problem into a number of smaller sub-problems and solve them individually. The Simple Multi-attribute Rating Technique (SMART), for example, is one of the methods in dealing with the multiattribute problems. Its main attraction is its relative simplicity, however, its main shortcoming is the poor accuracy (Goodwin & Wright, 1998) Nevertheless, the assessment of value functions and swing weights can still be difficult tasks and the resulting decision model may therefore be an inaccurate reflection of the decision-maker s true preferences. Decision tree is a useful tool for people to gain a deeper understanding of complex problems, but it deals with deci- Fig. 2. The hierarchy of the comprehensive assessment framework for scaffoldings.

3 D. Fang et al. / Journal of Safety Research 34 (2003) Table 1 Example of Data Analysis from the Questionnaire Cost vs. Benefit Equally Slightly Obviously Very Absolutely Benefit vs. Cost Slightly Obviously Very No. of respondents Absolutely sion problems that consist of multi-stages. It also involves continuous probability distributions, which makes it difficult to use in practice. Scenario planning is another way of evaluating decision options, but it is a practitioner-derived approach to dealing with uncertainty in decision-making. It is not based on an axiom system, and different practitioners tend to promote different methodologies to construct scenarios (Goodwin & Wright, 1998). In our framework, we have proposed to use an alternative-analytic hierarchy process (AHP). It offers a number of advantages over methods mentioned previously. Its widespread use has proved its popularity among decisionmakers. The relative strengths of AHP include: (a) formal structuring of problem; (b) simplicity of pair-wise comparisons; (c) redundancy allows consistency to be checked; and (d) versatility. AHP offers an alternative approach when a decision-maker is faced with a problem involving multiple objectives. The method, which was originally developed by Thomas Saaty (1980), has been widely used in decision problems in areas such as economics and planning, energy policy, material handling and purchasing, and project selection. The process consists of the following major steps: Step 1: Set up the decision hierarchy, Step 2: Make pair-wise comparisons of attributes and alternatives, Step 3: Transform the comparisons into weightings and check the consistency of the decision-maker s comparisons, Step 4: Use the weightings to obtain scores for the different options and make a regional decision. 3. The framework for assessment of scaffoldings In order to make a more comprehensive, accurate, and objective assessment of different types of scaffoldings, a Table 2 Mean Values of Pair-wise Comparisons By Respondents Comparisons Mean Value A (B1 f B2) B1 (C1 f C2) B2 (C3 f C4) C1 (D1 f D2) C2 (D3 f D4) C3 (D5 f D6) C4 (D7 f D8) comprehensive assessment framework was developed to compare and select scaffoldings, based on the use of AHP. This model can take into account a number of tangible (e.g., investment and cost) and intangible factors (e.g., quality and risk) in the assessment. To the main contractors, two factors are of paramount importance in the selection of scaffolding: cost and benefit. Both of them can be further divided into a number of sub-factors. As shown in Fig. 2, there are four levels of factors in our assessment model: Level A: Overall objectives Level B: Set of factors (cost and benefit) Level C: Subset of factors (expenses, risks, efficiency, and social benefit) Level D: Sub-subset of factors (initial cost, running cost, safety risks, cost variation, speed of installation and dismantle, efficiency of other trades, corporate image, and project quality) These factors and the hierarchy were identified by repeatedly interviewing, consulting, and discussing with a large number of professional and managerial staff in the construction industry. They included safety officials from the Works Bureau, Labor Department, and Architectural Services Department in Hong Kong, scaffolding professionals from the Construction Industry Training Authority, and safety officers, project managers, and scaffolding experts from contractors and scaffolding suppliers. Among these factors, initial cost means scaffoldingrelated costs that occurs at the beginning of a construction a project. Running cost is the scaffolding-related costs that occur on a monthly basis during the construction of a project. Safety risks are the risks of having scaffoldingrelated accidents. Cost variation is the extra portion of the cost that exceeds the original budget. Speed of installation and dismantle is the speed of installing and dismantling scaffolding. Efficiency of other trades means the efficiencies of other trades who use the scaffolding to complete their work. Corporate image means public image of the company Table 3 The impact of cost and benefit on the overall objective Importance Cost Benefit Cost Benefit 1/ Eigenvector

4 592 D. Fang et al. / Journal of Safety Research 34 (2003) Table 4 The impact of expenses and risks on cost Importance Expenses Risks Expenses Risks 1/ Eigenvector Table 6 The impact of initial cost and running cost on expenses Importance Initial Cost Running Cost Initial Cost Running Cost 1/ Eigenvector as a result of using a particular type of scaffolding. Project quality means the quality of the project as a result of using a particular type of scaffolding Determining the weightings of factors According to the above assessment framework, a weighting was assigned to each of the factors on the 4th level, and scores were given for bamboo and metal scaffolding with respect to each of these factors. The weightings were obtained through a purpose-designed questionnaire completed by 23 industry professionals in 23 construction projects. The respondents were carefully selected project managers who had knowledge of the economic and safety aspects of scaffoldings, and had extensive experience in the selection of scaffoldings. They were recommended by contractors, suppliers of scaffoldings, and relevant departments of the Government of the Hong Kong Special Administrative Region. The projects managed by the respondents included schools, apartments, hospitals, and offices. The scores for the two types of scaffolding were given based on the primary data collected from the construction sites (Wu, 2002). For some intangible elements, AHP is used to make comparative analyses. The responses given by the 23 project managers for each comparison were averaged to obtain the mean value. Table 1 illustrates this process of data analysis. According to AHP, the wordings for comparison in Table 1 should be converted to numerical values in order to calculate the weightings. Saaty (1980) suggests using a scale of 1 to 9. However, the pair-wise comparisons in this scale are more likely to cause inconsistencies among the decision-makers, which is a well-known problem to AHP researchers (Finan & Hurley, 1999). In order to avoid the inconsistency problem, our assessment framework adopted the scale suggested by Finan (1999; i.e., using 1, 3 1/4,3 1/2, 3, 9 to represent equally, slightly, obviously, very, absolutely. ) When the judgment meets the consistency requirement, the judgment matrix can be considered as a consistent matrix for further analysis. Table 5 The impact of efficiency and social factors on benefit Importance Efficiency Social Factors Efficiency Social Factors 1/ Eigenvector Assuming project manager k believes that the relative importance of factor i over factor j is a ij k, the average importance assigned by all project managers (K) can be calculated through the mean value as shown in formula (1). a ij ¼ X K a k ij k¼1 K ð1þ If i is more than j, then use a ij k to calculate the mean If j is more than i, then use a ij k = 1/a ji k to calculate the mean For example, the relative importance of B1 over B2 can be calculated by using Table 1 and the above formula as follows: 13 1 þ 2 3 1=4 þ 1 3 1=2 þ 0 3 þ 0 9 þ þ 3 1 1=4 3 þ 1 1 1=2 3 þ 0 1 =23 ¼ 0:944 9 Other pair-wise comparisons can be calculated in the same way, and the results are shown in Table 2. The use of the mean value reflects the views of the entire sample, and reduces the possible strong influence of an individual project manager. Based on Table 2, we can establish a number of comparison matrices for the pair-wise comparisons and obtain their eigenvectors as shown in Tables 3 9. The above pair-wise comparisons are integrated according to the hierarchical structure shown in Fig. 2 to obtain the weightings of various major factors in the assessment and selection of scaffoldings, as shown in Table 10. Among these factors, safety (D3), efficiency of other trades (D6), and speed of installation (D5) have the biggest weighting. This means that project managers in the survey give more considerations to safety and efficiency of the work. The above results represent the views of the 23 experienced project managers involved in the survey. Their views Table 7 The impact of safety risks and cost variation on risks Importance Safety Risks Cost Variation Safety Risks Cost Variation 1/ Eigenvector

5 D. Fang et al. / Journal of Safety Research 34 (2003) Table 8 The impact of speed of installation and efficiency of other trades on efficiency Importance Speed of Installation Speed of Installation Efficiency of Other Trades 1/ Eigenvector Efficiency of Other Trades can be regarded as a reflection of the general views of project managers in Hong Kong, due to the experiences and qualifications of these respondents. The comprehensive assessment framework proposed here can be used as a decision support tool in the assessment and selection of a specific type of scaffolding for a project. The use of the framework can best be illustrated through a hypothetical project, provided in the next section Assigning values to factors and removing their dimensions In this section, the framework is illustrated through a hypothetical case. The case is as follows: A construction project has an area of 30,000 square meters of scaffolding work and the duration of construction is 18 months. The contractor has two choices of scaffolding: bamboo and metal. According to the current market price, the bamboo scaffolding costs HK$100/m 2, where the metal scaffolding costs HK$210/ m 2. Since the market price of metal scaffolding may drop significantly if it is used more widely, another three prices of HK$180, HK$150, and HK$100/m 2 are also taken into consideration. Values of the factors can be assigned according to the real situation through the proposed method. The data used in this case are based on interviews and surveys conducted by the Tsinghua-Gammon Construction Safety Research Center (2001). 1) Initial cost it is 20% of the total cost of scaffolding work, which will be paid at the commencement of the construction. For example, the initial cost for the bamboo scaffolding is calculated like this: 30,000 m 2 HK$100/m 2 20% = HK$600,000. 2) Running cost it is 80% of the total cost of scaffolding work, which will be paid monthly during the construction of the project. For example, the running cost Table 10 Calculated weightings of major factors in the assessment of scaffoldings Level Factors and Weighting Weighting on Level 4 B C B*C D D D D D D D D for the bamboo scaffolding is calculated: 30,000m 2 HK$100/m 2 80%/18 = HK$133,300. 3) Safety risks A comparison of safety performance between the two types of scaffoldings shows that metal scaffolding is superior to bamboo scaffolding. The average accident risk index of metal scaffolding is 0.35, while that of bamboo scaffolding is ) Cost variation This is the excess of actual cost over the original budget. Cost variation of bamboo scaffolding is around 5% of the budget on average (i.e. 30,000 m 2 HK$100/m 2 5% = HK$150,000), whereas the metal scaffolding has almost no cost variation. 5) Speed of installation and demolition Although the speed of installation and demolition of bamboo scaffolding is faster than that of metal scaffolding, from the contractor s perspective, this does not have any impact on the timely completion of the project (because the scaffolding work is subcontracted out to a scaffolding sub-contractor, who can put more labor resources to ensure timely completion of the scaffolding work). 6) Efficiency of other trades Scaffolding has some impacts on the efficiency of other trades involved in the project. However, due to the widely implemented sub-contracting system in the construction industry in Hong Kong, all sub-contractors have to find their own ways to complete their work within the contract period. To the main contractor, the impact of scaffolding on the efficiency of other trades is negligible. 7) Project quality The safety of the working environment has a direct impact on workers productivity and the quality of their work. In the purpose-designed questionnaire, two questions about the impact of the working environment of the two types of scaffoldings on project Table 9 The impact of project quality and corporate image on social factors Importance Project Quality Corporate Image Project Quality Corporate Image 1/ Eigenvector Table 11 The impact of two types of scaffoldings on project quality Importance Bamboo Metal Bamboo 1 1/2.673 Metal Eigenvector

6 594 D. Fang et al. / Journal of Safety Research 34 (2003) Table 12 The impact of two types of scaffoldings on corporate image Importance Bamboo Metal Bamboo 1 1/3.470 Metal Eigenvector quality are designed and analyzed through AHP method as shown in Table 11. 8) Corporate Image similar questions on the impact of scaffolding on corporate image are designed in the purpose-designed questionnaire and analyzed as shown in Table 12. The above data are summarized in Table 13. The best and worst scenarios are taken into consideration as shown in Table 14. It is assumed that the best and the worst values for safety risks, project quality, and corporate image are either increased or decreased by 10% of the corresponding values in Table 13. For bamboo scaffolding, the worst value of cost variation is 20% of the total scaffolding cost as stated in the report by Tsinghua-Gammon Construction Safety Research Center (2001). Since factors in Table 13 have different dimensions, it is not suitable to calculate a weighted average value of factors. In our proposed framework, the values of the factors are converted into dimensionless relative values with a range between 0 and 1 as shown in Table 15. The dimensions are removed by using the following formulae (2) and (3) (Hu & He, 2000). Positive factors : Negative factors : y i ¼ x i x im y i ¼ x im þ x in x i x im ð2þ ð3þ Positive factors: the larger the factors the better the overall performance. Negative factors: the smaller the factors the better the overall performance. Xi is the values of the factors. Yi is dimensionless relative value. X im and X in are the maximum and minimum values of the factors as shown in Table Comprehensive assessment As shown in Table 10, the weighting vector for factors on the 4th level is B = { }. The results of the comprehensive assessment of scaffoldings can be obtained by multiplying vector B with the dimensionless factor-value matrix C (Table 15): A ¼ðA1; A2; A3; A4; A5Þ ¼B C ¼f0:12 0:13 0:18 0:05 0:15 0:18 0:13 0:06g :48 0:62 0: :48 0:62 0:76 1 0:54 0:96 0:96 0:96 0:96 0: B 0:34 0:91 0:91 0:91 0:91 A 0:26 0:91 0:91 0:91 0:91 ¼ð0:775 0:845 0:880 0:916 0:976Þ A is the final result for the comprehensive comparison between metal scaffolding and bamboo scaffolding. A1 represents the overall performance of bamboo scaffolding; A2, A3, A4, A5 is overall performance indices of metal scaffolding with the cost of HK$210, HK$180, HK$150, HK$100 per square meter respectively. From the above analysis, metal scaffolding is superior to bamboo scaffolding with the major quantitative and qualitative factors considered. It also shows that the lower the cost, the better the overall performance of the metal scaffolding. 4. Discussions If corporate image and project quality are excluded from the assessment, the contractor prefers bamboo scaffolding. Table 13 Actual values of major factors in the assessment of scaffoldings Initial cost Running cost Safety risks Cost variation Speed of installation Efficiency of other trades Project quality (1) (2) (3) (4) (5) (6) (7) (8) Bamboo HK$100/m Metal HK$210/m Metal HK$180/m Metal HK$150/m Metal HK$100/m Corporate Image

7 D. Fang et al. / Journal of Safety Research 34 (2003) Table 14 The best and worst scenarios among options in Table 13 Initial cost Running cost Safety risks Cost variation Speed of installation Efficiency of other trades Project quality (1) (2) (3) (4) (5) (6) (7) (8) Best Worst Corporate Image Corporate image and project quality are intangible benefits to the contractor, which affect contractors long-term interest but have little impact on the interest of the project. In practice, project managers generally focus on the project s economic performance. It is believed that metal scaffolding and bamboo scaffolding have the same impact on corporate image and project quality. A sensitivity analysis is made to explain what impact on the comprehensive assessment would be caused if the condition was considered. In each column of factors of project quality and corporate image, each alternative is assigned to the same value. The left factors remain unchanged as shown in Table 13. The comprehensive assessment is now ( ). From the result, the overall performance of bamboo scaffolding is better than the metal scaffolding with the present market price of HK$210/m 2 for metal scaffolding. This partially explains why bamboo scaffolding is widely used in Hong Kong. However, if the market price of metal scaffolding drops down to HK$150/m 2, the overall performance of metal scaffolding will be superior over bamboo scaffolding. It indicates that with the increase in market share and the decrease in price, metal scaffolding will take over bamboo scaffolding and become the leading type of scaffolding in the future. If safety risks of the two types of scaffoldings are treated the same, it s inevitable for the contractors to select bamboo scaffolding. Because of uncertainty of possible accidents, the use of bamboo scaffolding may not definitely cause accidents despite its poor safety records. For this reason, many project managers wrongly believe that accidents may not occur to their projects if management is strengthened. Similar to the previous discussion, sensitivity analysis is made in the similar way. In each column of factors of safety risks, project quality, and corporate image, each alternative is assigned with the same value. The comprehensive assessment result is now ( ) and it proves that the overall performance of bamboo scaffolding is far better than the metal scaffolding with the present market price of HK$210/m 2. Only the metal scaffolding with the cost of HK$100/m 2 is better than the bamboo scaffolding. It implies that without the emphasis on safety, the contractor will surely select bamboo scaffolding until the price of metal scaffolding drops to a level similar to bamboo scaffolding in the future. 5. Conclusions This paper proposes a comprehensive assessment framework, which takes a number of major quantitative and qualitative factors into consideration in the selection of scaffolding. This framework is based on the AHP method and a survey among project managers in Hong Kong. The research reveals that the overall performance of metal scaffolding is believed to be better than bamboo scaffolding in Hong Kong. Among the major criteria that guide contractors in the selection of scaffolding, the primary considerations are safety and efficiency, followed by the cost of the scaffolding. In the present market situation, if two intangible factors of corporate image and project quality are excluded from the evaluation criteria, the overall performance of bamboo scaffolding is better than metal scaffolding. If the factor of safety risks is excluded as well, bamboo scaffolding is surely superior to metal scaffolding due to its cost advantage. Since these three factors have no direct impact on the economic performance at project level, project managers in Hong Kong frequently select bamboo scaffolding. It is suggested that the Hong Kong Government should take clear measures to promote the wide use of metal scaffolding according to the comprehensive assessment result. This proposed framework provides a very useful decision support tool for project managers in the selection of scaffoldings for Table 15 Dimensionless relative values of major factors in the assessment of scaffoldings Initial cost Running cost Safety risks Cost variation Speed of installation Efficiency of other trades Project quality (1) (2) (3) (4) (5) (6) (7) (8) Bamboo HK$100/m Metal HK$210/m Metal HK$180/m Metal HK$150/m Metal HK$100/m Corporate Image

8 596 D. Fang et al. / Journal of Safety Research 34 (2003) their projects. Further research has been planned to conduct a survey of wider coverage of project managers to enable the generalization of these research findings. Acknowledgements Special appreciation is given to the Works Bureau and Gammon Skanska Construction Ltd. for their great support and funding. Appreciation is also given to the Labor Department, and Architectural Services Department of Hong Kong, Construction Industry Training Authority, Wei Loong Scaffolding Works Co. Ltd. and AES Scaffolding Engineering Ltd. etc. for their great support to this research. Professor Francis Wong and Albert Kwok of Hong Kong Polytechnic University and Professor S.W. Poon of Hong Kong University contributed their knowledge and experience. This research was also supported by the National Natural Science Foundation of China (Grant number ) and the Beijing Natural Science Foundation (Grant number ). References Chan, S. L., Wong, F. K. W., So, F. Y. S., & Poon, S. W. (1998). Empirical design and structural performance of bamboo scaffolding. Proceedings of Symposium on Bamboo and Metal Scaffolding, Finan, J. S., & Hurley, W. J. (1999). Transitive calibration of the AHP verbal scale. European Journal of Operational Research, 112, Fu, W. Y. (1993). Housing department, Hong Kong government, Bamboo scaffolding in Hong Kong. The structural engineer, 71(11), Goodwin, P., & Wright, G. (1998). Decision analysis for management judgment (2nd ed.). New York: Wiley. Hu, Y. H., & He, S. H. (2000). Comprehensive assessment approaches. Beijing: Science Press. Mak, D. H. K. (1998). Labor Department, The Government of the Hong Kong Special Administrative Region, Legislative Control Regime for Ensuring Safe Use of Scaffolding. Proceedings of Symposium on Bamboo and Metal Scaffolding, Saaty, T. L. (1980). The analytical hierarchy process: Planning, priority setting, resource allocation. London, England: McGraw-Hill International Book Co. Tsinghua-Gammon Construction Safety Research Center. (2001). Comparative study on safety and application of bamboo and metal scaffolding in Hong Kong, Report Hong Kong: Author. Tong, A. Y. C. (1998). Bamboo Scaffolding-Practical Application. Proceedings Symposium on Bamboo and Metal Scaffolding ( pp ). Wong, F. K. W. (1998). Bamboo scaffolding-safety Management for the Building Industry in Hong Kong. Wu, S.H. (2002). Safety, Economy and Synthetic Assessment for Scaffolding System. Unpublished master s thesis, Tsinghua University, Beijing. Professor Dongping Fang is the director of (Tsinghua University-Gammon Skanska) Construction Safety Research Center in the Department of Construction Management of the School of Civil Engineering at Tsinghua University, Beijing, China. He received his first degree and Master of Science from Xi an Jiaotong University, China, and Master of Engineering from Iwate University and Ph.D from Kyushu University, Japan. His research activity has been in the area of structural engineering and construction management with more than 80 journal and conference papers, books, and reports published in English, Japanese and Chinese. Professionally, he is a member of CIOB (Chartered Institute of Builders, UK), the alternate delegate (China) to IABSE (International Association of Bridge and Structural Engineering), a member of WP2, JCSS (Joint Committee on Structural Safety), a board member of the society of China working protection science and technology and the vice chair of the construction safety specialist group of building technology specialist committee of the Ministry of Construction, China. Professor Qiping Shen works in the Department of Building and Real Estate, The Hong Kong Polytechnic University. As an active researcher in value management and related fields, he has managed a large number of research projects with total funding over HK$10 million, and has published more than 150 journal and conference papers, books, and reports. He also teaches extensively in this field at both postgraduate and degree levels, and has successfully supervised a number of PhD and MSc students. Professionally, he is a member of the Institute of Value Management in the UK and a founding council member of the Hong Kong Institute of Value Management (HKIVM). He has been serving the HKIVM as the Secretary, Councillor, Editor, and Member of the Executive Committee since its formation in As a certified Value Management Facilitator (List A) recognised by the Hong Kong SAR Government, he has professionally facilitated a large number of value management and partnering workshops for a variety of large client organisations in both the public and private sectors in Hong Kong. He is elected as the Vice-Chairman of China Value Engineering Association and Vice President of the Value Engineering Institute of China Association for Tertiary Education. Mr. Shenghou Wu works in B. A. Real Estate Investment Consulting Co., Ltd. as a consultant. He got his Bachelors and Master s degree from the School of Civil Engineering, Tsinghua University, Beijing, China Mr. Guiwen Liu is a PhD candidate in the Department of Building and Real Estate of the Hong Kong Polytechnic University. He obtained his bachelor s degree in Project Management and his master s degree in Construction Management and Economics from Chongqing Jianzhu University, P.R. China. He is a member of the Hong Kong Institute of Value Management and a member of the Chinese Research Institute of Construction Management. His research interests cover the areas of value management, strategic management, project management, and construction and real estate economics. To date, he has successfully completed a number of research projects, including the national eight-five key project for formulating 3-A housing standards, the value management framework for applying VM in China, etc. He has published over 20 influential papers at journals and international conference proceedings.