The process of decision making and risk analysis are essential tasks along the construction project cycle. Over the years, construction practitioners and researchers have used various methods, tools and techniques to ...The process of decision making and risk analysis are essential tasks along the construction project cycle. Over the years, construction practitioners and researchers have used various methods, tools and techniques to evaluate risk and assist in making more concise decisions. Most practitioners, however, rely on their expert judgment, past experience, intuition, acquired and accumulated knowledge and gut feelings to make decisions. Aleatory （natural, heterogeneity and stochasticity） and epistemic （subjective, ignorance） are the two major types of uncertainties observed in natural sciences. Practitioners traditionally deal with aleatory uncertainty through probabilistic analysis based on historical data （frequentist approach）; and epistemic uncertainty, on the other hand, handled through the Bayesian approach which has limitations since it requires a priori assumption. This paper reports the application of the DST （Dempster Shafer Theory） of evidence to determine the most critical risk factors affecting project cost contingencies using their epistemic probabilities of occurrence. The paper further discuses how these factors can be managed to enhance successful delivery of infrastructural projects. It uses the mixed methodology, with data gathered through structured questionnaires distributed to construction clients, contractors, professionals and experts in the built environment. The research revealed that design risk, financial risk and economic risk were most important cost risk categorizations. In particular, scope changes, incomplete scope definition, incomplete design, changes in specification, micro and macroeconomic indicators and delayed payment problems were identified as the most important risk factors to be considered during the cost contingency estimation process, hence successful delivery of infrastructural projects. The paper concludes by recommending modalities for managing the contingency evolution process of risk estimation to enhance successful delivery and management of infrastructural projects.展开更多
In order to achieve high quality that not only gives acceptable return value to society but also satisfies the needs of all the stakeholders of infrastructure projects, comprehensive understanding of issues pertaining...In order to achieve high quality that not only gives acceptable return value to society but also satisfies the needs of all the stakeholders of infrastructure projects, comprehensive understanding of issues pertaining to the quality of the project is needed. The aim of this study is to provide an overview the most common procurement methods used in constructing infrastructure transport projects and analyze how these methods contribute to the desired quality of the final product in relation to client competence. An on-line survey of construction actors was carried out to ascertain quality level of Swedish infrastructure transport projects and determinant factors of quality problems. An equal number of respondents indicated that the quality of infrastructure projects has either increased or remained same level over the past twenty years. Respondents also pointed out lack of client competence that is vital in realizing the desired quality level through proper procurement, monitoring and evaluation procedures. Public clients heavily rely on traditional design-build procurement that requires considerable client involvement of a project. Thus, the association of quality problems and lack of client competence may not be a mere coincidence but an overlooked outcome of current situation.展开更多
Communication based train control systems （CBTC） must work even in the worst situation-- train crossing. This paper models the propagation characteristics in one of the most common and piv- otal scenarios--train cro...Communication based train control systems （CBTC） must work even in the worst situation-- train crossing. This paper models the propagation characteristics in one of the most common and piv- otal scenarios--train crossing in subway tunnels which is rarely mentioned in previous publications. Firstly, measurements for train crossing scenario at 2.4 GHz in a real subway line in Madrid have been made. The field measurement is the most reliable way to reveal the propagation characteristics involving shadowing effect and fast fading. Moreover, to precisely describe the fast fading distribu- tion and eliminate the inevitable weak points of traditional fitting way, a best numerical approxima- tion method using Legendre orthogonal polynomials has been proposed. Comparisons show that this method works better and is of greater physical significance. Finally, a complete statistical model is given and all the coefficients can be applied by system designers for the link and system level simu- lations.展开更多
Quality is considered as one of the most important elements in the construction industry. The factors affecting quality in the construction industry should be assessed. This paper aims to introduce a new model to asse...Quality is considered as one of the most important elements in the construction industry. The factors affecting quality in the construction industry should be assessed. This paper aims to introduce a new model to assess these factors. The model is namely Fuzzy Assessment Model for Quality （FAMQ）. Fuzzy set theory provides a useful way to deal with ill-defined and complex problems in a decision-making environment that incorporates vagueness. The proposed model employs the combined effect of both; the factors probability of occurrence and their impacts on the quality of construction. Twenty five logical rules for each factor were implemented in the model. The model was evaluated using data that collected from the infrastructure projects in Egypt. It was applied to many factors that affect the quality of this kind of projects as a case study. The results of the study proved that the proposed model can be used successfully in the assessment of factors affecting quality in the construction industry. In addition, the results provided a platform of useful assessment reference to those infrastructure＇s finns, who plan to establish their businesses in Egypt.展开更多
The paper analyzes existing state of innovation system in the field of public infrastructure construction in China and elaborates on the duty and role of owner in establishment of a technical innovation system with en...The paper analyzes existing state of innovation system in the field of public infrastructure construction in China and elaborates on the duty and role of owner in establishment of a technical innovation system with enterprise as the main body following the process of production-education-research.This paper also claims that the key project construction is an important resource to enhance national capability of innovation and accordingly puts forward an effective approach to cultivate the core competitiveness of leading enterprises on the basis of practice in the Sutong Bridge project.展开更多
The construction industry is a sector that contributes a lot to the economic growth of Malaysia, as it is developing rapidly similar in fashion to other developing countries around the world. In line with the 9th Mala...The construction industry is a sector that contributes a lot to the economic growth of Malaysia, as it is developing rapidly similar in fashion to other developing countries around the world. In line with the 9th Malaysia Plan, development in Malaysia must meet current and future needs to achieve sustainability in economic development, as well as functioning as a social and environmental responsibility for prosperity without compromising the needs of future generations. To ensure that the government＇s objective is met, construction industry should implement the LCC （life cycle costing） method in structure and infrastructure projects so as to not cause losses to the industry itself and to the government. Through LCC, factors contributing to, and the associated cost of maintenance works for a building are identified at the design stage to obtain a more accurate projection of the total cost. This paper describes the LCC as a vital element in the construction industry since this method can drive quality improvement by taking into account the comprehensive cost of a project. The main aim of this paper is to aid in understanding the application of the LCC concept for the construction industry, particularly for the maintenance phase. This paper also identifies LCC processes involved in a building construction project and subsequently provides recommendation on appropriate measures to implement LCC in the construction industry in Malaysia.展开更多
Adopting the BOT （build-operate-transfer） delivery method has brought opportunities and challenges in construction time and quality for urban infrastructure. Many studies investigate the upstream issues of BOT proje...Adopting the BOT （build-operate-transfer） delivery method has brought opportunities and challenges in construction time and quality for urban infrastructure. Many studies investigate the upstream issues of BOT projects such as concessionaire selection criteria and risk factors. But the project execution becomes complicated such as the escalated quality supervision organization and procedure at the construction stage. This extra supervision may have constituted hidden redundancies as waste to economic sustainability. This paper investigated construction quality supervision of BOT projects to pinpoint adequate degree of supervision and detect redundant organization and procedures. The study adopted ten subway construction projects as cases in which five were from the traditional design-bid-build （DBB） and five from the BOT methods. Thirty six project participants including owners, contractors, designers, and concessionaire managers of the ten projects were interviewed to tell their views on these issues. The quality supervision measures of the DBB projects were used as the baseline and compared with those of the BOT projects. The research results show that the construction quality seems no difference for the DBB and BOT projects. Construction quality comes out of supervision but excessive supervision organization and procedures do not necessarily improve quality. This finding indicates that adequate degree of supervision is enough to achieve required quality to save immense paperwork for large construction projects.展开更多
The article analyzes the current situation of city infrastructure construction in China, elaborated needs if our country city infrastructure construction projects in various stages of information management, a framewo...The article analyzes the current situation of city infrastructure construction in China, elaborated needs if our country city infrastructure construction projects in various stages of information management, a framework of information platform are presented for city infrastructure projects of our construction comprehensive control, and efficient management city infrastructure construction project, and provide collaboration platform for the party in the infrastructure construction projects.展开更多
Public-Private Partnership （PPP） financing modalily has the ability of alleviating the budgetary pressure to the government. fulfilling the need of infrastructure development, and improving the efficiency of investm...Public-Private Partnership （PPP） financing modalily has the ability of alleviating the budgetary pressure to the government. fulfilling the need of infrastructure development, and improving the efficiency of investment and operation. However, the negotiations between the government and the investors are time-consuming and costly, due to the perspective differences in risk allocation and revenue distribution. Disputes often arise during concession period because of changes in various risks or non-performance of its obligalions, especially when one sector was forced to accept the requirements by the other as a result of the unequal status, the project urgency or other reasons. Only a few PPP projects in China could perform successfully. There is therefore a need to develop an equitable risk allocation mechanism for the delivery of PPP projects in China so as to improve the efficiency of private investment in infrastructure development.展开更多
文摘The process of decision making and risk analysis are essential tasks along the construction project cycle. Over the years, construction practitioners and researchers have used various methods, tools and techniques to evaluate risk and assist in making more concise decisions. Most practitioners, however, rely on their expert judgment, past experience, intuition, acquired and accumulated knowledge and gut feelings to make decisions. Aleatory （natural, heterogeneity and stochasticity） and epistemic （subjective, ignorance） are the two major types of uncertainties observed in natural sciences. Practitioners traditionally deal with aleatory uncertainty through probabilistic analysis based on historical data （frequentist approach）; and epistemic uncertainty, on the other hand, handled through the Bayesian approach which has limitations since it requires a priori assumption. This paper reports the application of the DST （Dempster Shafer Theory） of evidence to determine the most critical risk factors affecting project cost contingencies using their epistemic probabilities of occurrence. The paper further discuses how these factors can be managed to enhance successful delivery of infrastructural projects. It uses the mixed methodology, with data gathered through structured questionnaires distributed to construction clients, contractors, professionals and experts in the built environment. The research revealed that design risk, financial risk and economic risk were most important cost risk categorizations. In particular, scope changes, incomplete scope definition, incomplete design, changes in specification, micro and macroeconomic indicators and delayed payment problems were identified as the most important risk factors to be considered during the cost contingency estimation process, hence successful delivery of infrastructural projects. The paper concludes by recommending modalities for managing the contingency evolution process of risk estimation to enhance successful delivery and management of infrastructural projects.
文摘In order to achieve high quality that not only gives acceptable return value to society but also satisfies the needs of all the stakeholders of infrastructure projects, comprehensive understanding of issues pertaining to the quality of the project is needed. The aim of this study is to provide an overview the most common procurement methods used in constructing infrastructure transport projects and analyze how these methods contribute to the desired quality of the final product in relation to client competence. An on-line survey of construction actors was carried out to ascertain quality level of Swedish infrastructure transport projects and determinant factors of quality problems. An equal number of respondents indicated that the quality of infrastructure projects has either increased or remained same level over the past twenty years. Respondents also pointed out lack of client competence that is vital in realizing the desired quality level through proper procurement, monitoring and evaluation procedures. Public clients heavily rely on traditional design-build procurement that requires considerable client involvement of a project. Thus, the association of quality problems and lack of client competence may not be a mere coincidence but an overlooked outcome of current situation.
基金Supported by the National Natural Science Foundation of China(No.60830001)Program for New Century Excellent Talents in University(No.NCET-09-0206)+2 种基金the Key Project of State Key Lab.of Rail Traffic Control and Safety(No.RCS2008ZZ006)Program for Changjiang Scholars and Innovative Research Team in University(No.IRT0949)the Project of State Key Lab.of Rail Traffic Control and Safety(No.RCS2008ZT005)
文摘Communication based train control systems （CBTC） must work even in the worst situation-- train crossing. This paper models the propagation characteristics in one of the most common and piv- otal scenarios--train crossing in subway tunnels which is rarely mentioned in previous publications. Firstly, measurements for train crossing scenario at 2.4 GHz in a real subway line in Madrid have been made. The field measurement is the most reliable way to reveal the propagation characteristics involving shadowing effect and fast fading. Moreover, to precisely describe the fast fading distribu- tion and eliminate the inevitable weak points of traditional fitting way, a best numerical approxima- tion method using Legendre orthogonal polynomials has been proposed. Comparisons show that this method works better and is of greater physical significance. Finally, a complete statistical model is given and all the coefficients can be applied by system designers for the link and system level simu- lations.
文摘Quality is considered as one of the most important elements in the construction industry. The factors affecting quality in the construction industry should be assessed. This paper aims to introduce a new model to assess these factors. The model is namely Fuzzy Assessment Model for Quality （FAMQ）. Fuzzy set theory provides a useful way to deal with ill-defined and complex problems in a decision-making environment that incorporates vagueness. The proposed model employs the combined effect of both; the factors probability of occurrence and their impacts on the quality of construction. Twenty five logical rules for each factor were implemented in the model. The model was evaluated using data that collected from the infrastructure projects in Egypt. It was applied to many factors that affect the quality of this kind of projects as a case study. The results of the study proved that the proposed model can be used successfully in the assessment of factors affecting quality in the construction industry. In addition, the results provided a platform of useful assessment reference to those infrastructure＇s finns, who plan to establish their businesses in Egypt.
基金National Science and Technology Support Program(No.2006BAG04B06)
文摘The paper analyzes existing state of innovation system in the field of public infrastructure construction in China and elaborates on the duty and role of owner in establishment of a technical innovation system with enterprise as the main body following the process of production-education-research.This paper also claims that the key project construction is an important resource to enhance national capability of innovation and accordingly puts forward an effective approach to cultivate the core competitiveness of leading enterprises on the basis of practice in the Sutong Bridge project.
文摘The construction industry is a sector that contributes a lot to the economic growth of Malaysia, as it is developing rapidly similar in fashion to other developing countries around the world. In line with the 9th Malaysia Plan, development in Malaysia must meet current and future needs to achieve sustainability in economic development, as well as functioning as a social and environmental responsibility for prosperity without compromising the needs of future generations. To ensure that the government＇s objective is met, construction industry should implement the LCC （life cycle costing） method in structure and infrastructure projects so as to not cause losses to the industry itself and to the government. Through LCC, factors contributing to, and the associated cost of maintenance works for a building are identified at the design stage to obtain a more accurate projection of the total cost. This paper describes the LCC as a vital element in the construction industry since this method can drive quality improvement by taking into account the comprehensive cost of a project. The main aim of this paper is to aid in understanding the application of the LCC concept for the construction industry, particularly for the maintenance phase. This paper also identifies LCC processes involved in a building construction project and subsequently provides recommendation on appropriate measures to implement LCC in the construction industry in Malaysia.
文摘Adopting the BOT （build-operate-transfer） delivery method has brought opportunities and challenges in construction time and quality for urban infrastructure. Many studies investigate the upstream issues of BOT projects such as concessionaire selection criteria and risk factors. But the project execution becomes complicated such as the escalated quality supervision organization and procedure at the construction stage. This extra supervision may have constituted hidden redundancies as waste to economic sustainability. This paper investigated construction quality supervision of BOT projects to pinpoint adequate degree of supervision and detect redundant organization and procedures. The study adopted ten subway construction projects as cases in which five were from the traditional design-bid-build （DBB） and five from the BOT methods. Thirty six project participants including owners, contractors, designers, and concessionaire managers of the ten projects were interviewed to tell their views on these issues. The quality supervision measures of the DBB projects were used as the baseline and compared with those of the BOT projects. The research results show that the construction quality seems no difference for the DBB and BOT projects. Construction quality comes out of supervision but excessive supervision organization and procedures do not necessarily improve quality. This finding indicates that adequate degree of supervision is enough to achieve required quality to save immense paperwork for large construction projects.
文摘The article analyzes the current situation of city infrastructure construction in China, elaborated needs if our country city infrastructure construction projects in various stages of information management, a framework of information platform are presented for city infrastructure projects of our construction comprehensive control, and efficient management city infrastructure construction project, and provide collaboration platform for the party in the infrastructure construction projects.
文摘Public-Private Partnership （PPP） financing modalily has the ability of alleviating the budgetary pressure to the government. fulfilling the need of infrastructure development, and improving the efficiency of investment and operation. However, the negotiations between the government and the investors are time-consuming and costly, due to the perspective differences in risk allocation and revenue distribution. Disputes often arise during concession period because of changes in various risks or non-performance of its obligalions, especially when one sector was forced to accept the requirements by the other as a result of the unequal status, the project urgency or other reasons. Only a few PPP projects in China could perform successfully. There is therefore a need to develop an equitable risk allocation mechanism for the delivery of PPP projects in China so as to improve the efficiency of private investment in infrastructure development.
